gpg



gpg(1)                                                                  gpg(1)




NAME

       gpg — encryption and signing tool


SYNOPSIS

       gpg  [--homedir name]  [--options file]  [options]  command  [args]


DESCRIPTION

       gpg is the main program for the GnuPG system.


       This  man page only lists the commands and options available.  For more
       verbose documentation get the GNU Privacy Handbook (GPH) or one of  the
       other documents at http://www.gnupg.org/documentation/ .

       Please  remember  that  option parsing stops as soon as a non option is
       encountered, you can explicitly stop option parsing by using  the  spe-
       cial option "--".


COMMANDS

       gpg  may  be run with no commands, in which case it will perform a rea-
       sonable action depending on the type of file it is given as  input  (an
       encrypted  message  is  decrypted, a signature is verified, a file con-
       taining keys is listed).

       gpg recognizes these commands:

       -s, --sign
                 Make a signature. This command may be combined with --encrypt
                 (for  a  signed  and  encrypted  message), --symmetric (for a
                 signed and symmetrically encrypted message), or --encrypt and
                 --symmetric  together  (for  a  signed  message  that  may be
                 decrypted via a secret key or a passphrase).

       --clearsign
                 Make a clear text signature.

       -b, --detach-sign
                 Make a detached signature.

       -e, --encrypt
                 Encrypt data. This option may be combined with --sign (for  a
                 signed  and  encrypted  message),  --symmetric (for a message
                 that may be decrypted via a secret key or a  passphrase),  or
                 --sign  and  --symmetric  together (for a signed message that
                 may be decrypted via a secret key or a passphrase).

       -c, --symmetric
                 Encrypt with a symmetric  cipher  using  a  passphrase.   The
                 default  symmetric  cipher  used  is CAST5, but may be chosen
                 with the --cipher-algo option.  This option may  be  combined
                 with  --sign  (for  a signed and symmetrically encrypted mes-
                 sage), --encrypt (for a message that may be decrypted  via  a
                 secret key or a passphrase), or --sign and --encrypt together
                 (for a signed message that may be decrypted via a secret  key
                 or a passphrase).

       --store   Store only (make a simple RFC1991 packet).

       --decrypt [file]
                 Decrypt  file (or stdin if no file is specified) and write it
                 to stdout (or the  file  specified  with  --output).  If  the
                 decrypted  file  is  signed,  the signature is also verified.
                 This command differs from the default operation, as it  never
                 writes  to  the filename which is included in the file and it
                 rejects files which don’t begin with an encrypted message.

       --verify [[sigfile]  [signed-files]]
                 Assume that sigfile is a signature and verify it without gen-
                 erating  any  output.    With  no  arguments,  the  signature
                 packet is read from stdin.  If only a sigfile  is  given,  it
                 may be a complete signature or a detached signature, in which
                 case the signed stuff is  expected  in  a  file  without  the
                 ".sig"  or  ".asc" extension.  With more than 1 argument, the
                 first should be a detached signature and the remaining  files
                 are  the  signed stuff.  To read the signed stuff from stdin,
                 use -  as  the  second  filename.   For  security  reasons  a
                 detached signature cannot read the signed material from stdin
                 without denoting it in the above way.

       --multifile
                 This modifies certain other commands to accept multiple files
                 for  processing  on  the command line or read from stdin with
                 each filename on a separate line.  This allows for many files
                 to  be  processed at once.  --multifile may currently be used
                 along with --verify, --encrypt,  and  --decrypt.   Note  that
                 ‘--multifile  --verify’  may not be used with detached signa-
                 tures.

       --verify-files [files]
                 Identical to ‘--multifile --verify’.

       --encrypt-files [files]
                 Identical to ‘--multifile --encrypt’.

       --decrypt-files [files]
                 Identical to ‘--multifile --decrypt’.

       --list-keys [names]

       --list-public-keys [names]
                 List all keys from the public  keyrings,  or  just  the  ones
                 given on the command line.

                 Avoid  using  the  output of this command in scripts or other
                 programs as it is likely to change  as  GnuPG  changes.   See
                 --with-colons  for  a  machine-parseable  key listing command
                 that is appropriate for use in scripts and other programs.

       -K, --list-secret-keys [names]
                 List all keys from the secret  keyrings,  or  just  the  ones
                 given  on  the  command  line.  A ’#’ after the letters ’sec’
                 means that the secret key is not usable (for example,  if  it
                 was created via --export-secret-subkeys).

       --list-sigs [names]
                 Same as --list-keys, but the signatures are listed too.

                 For each signature listed, there are several flags in between
                 the "sig" tag and keyid.  These flags give additional  infor-
                 mation  about  each  signature.  From left to right, they are
                 the numbers 1-3 for certificate check level (see  --ask-cert-
                 level),  "L"  for  a  local  or non-exportable signature (see
                 --lsign-key), "R"  for  a  nonRevocable  signature  (see  the
                 --edit-key  command  "nrsign"), "P" for a signature that con-
                 tains a policy URL (see --cert-policy-url), "N" for a  signa-
                 ture  that contains a notation (see --cert-notation), "X" for
                 an eXpired signature (see --ask-cert-expire), and the numbers
                 1-9  or  "T"  for  10  and  above to indicate trust signature
                 levels (see the --edit-key command "tsign").

       --check-sigs [names]
                 Same as --list-sigs, but the signatures are verified.

       --fingerprint [names]
                 List all keys with their fingerprints. This is the same  out-
                 put  as  --list-keys but with the additional output of a line
                 with the fingerprint. May also be combined  with  --list-sigs
                 or --check-sigs.  If this command is given twice, the finger-
                 prints of all secondary keys are listed too.

       --list-packets
                 List only the sequence of packets. This is mainly useful  for
                 debugging.

       --gen-key Generate  a  new key pair. This command is normally only used
                 interactively.

                 There is an experimental feature which allows you  to  create
                 keys  in  batch  mode. See the file doc/DETAILS in the source
                 distribution on how to use this.

       --edit-key name
                 Present a menu which enables you to do all key related tasks:

                 sign      Make  a signature on key of user name If the key is
                           not yet signed by the default user  (or  the  users
                           given  with  -u), the program displays the informa-
                           tion of the key again, together  with  its  finger-
                           print  and  asks  whether it should be signed. This
                           question is repeated for all users  specified  with
                           -u.

                 lsign     Same  as "sign" but the signature is marked as non-
                           exportable and will therefore never be used by oth-
                           ers.   This  may be used to make keys valid only in
                           the local environment.

                 nrsign    Same as "sign" but the signature is marked as  non-
                           revocable and can therefore never be revoked.

                 tsign     Make  a  trust signature.  This is a signature that
                           combines the notions of certification (like a regu-
                           lar  signature),  and  trust (like the "trust" com-
                           mand).  It is generally  only  useful  in  distinct
                           communities or groups.

                 Note  that  "l"  (for local / non-exportable), "nr" (for non-
                 revocable, and "t" (for trust) may be freely mixed  and  pre-
                 fixed to "sign" to create a signature of any type desired.

                 revsig    Revoke  a signature.  For every signature which has
                           been generated by one of  the  secret  keys,  GnuPG
                           asks  whether  a  revocation  certificate should be
                           generated.

                 trust     Change the owner  trust  value.  This  updates  the
                           trust-db immediately and no save is required.

                 disable

                 enable    Disable or enable an entire key. A disabled key can
                           not normally be used for encryption.

                 adduid    Create an alternate user id.

                 addphoto  Create a photographic user id.   This  will  prompt
                           for a JPEG file that will be embedded into the user
                           ID.  Note that a very large JPEG will  make  for  a
                           very  large key.  Also note that some programs will
                           display your JPEG unchanged (GnuPG), and some  pro-
                           grams will scale it to fit in a dialog box (PGP).

                 deluid    Delete a user id.

                 delsig    Delete a signature.

                 revuid    Revoke a user id.

                 addkey    Add a subkey to this key.

                 addcardkey
                           Generate a key on a card and add it to this key.

                 keytocard Transfer  the  selected  secret key (or the primary
                           key if no key has been selected)  to  a  smartcard.
                           The secret key in the keyring will be replaced by a
                           stub if the key could be stored successfully on the
                           card and you use the save command later.  Only cer-
                           tain key types may be transferred to the  card.   A
                           sub menu allows you to select on what card to store
                           the key.  Note that it is not possible to get  that
                           key  back  from  the card - if the card gets broken
                           your secret key will be  lost  unless  you  have  a
                           backup somewhere.

                 bkuptocard file
                           Restore  the given file to a card. This command may
                           be used to restore a backup key (as generated  dur-
                           ing  card initialization) to a new card.  In almost
                           all cases this will  be  the  encryption  key.  You
                           should use this command only with the corresponding
                           public key and make sure that  the  file  given  as
                           argument  is  indeed  the  backup  to restore.  You
                           should then select 2 to restore as encryption  key.
                           You  will first be asked to enter the passphrase of
                           the backup key and then for the Admin  PIN  of  the
                           card.

                 delkey    Remove a subkey.

                 addrevoker [sensitive]
                           Add  a designated revoker.  This takes one optional
                           argument: "sensitive".  If a designated revoker  is
                           marked  as  sensitive,  it  will not be exported by
                           default (see export-options).

                 revkey    Revoke a subkey.

                 expire    Change the key expiration time.   If  a  subkey  is
                           selected,  the  expiration time of this subkey will
                           be changed.  With no selection, the key  expiration
                           of the primary key is changed.

                 passwd    Change the passphrase of the secret key.

                 primary   Flag  the  current  user  id  as  the  primary one,
                           removes the primary user id  flag  from  all  other
                           user  ids  and  sets  the timestamp of all affected
                           self-signatures one second ahead.  Note  that  set-
                           ting  a  photo  user ID as primary makes it primary
                           over other photo user IDs, and  setting  a  regular
                           user  ID  as  primary  makes  it primary over other
                           regular user IDs.

                 uid n     Toggle selection of user id with index n.  Use 0 to
                           deselect all.

                 key n     Toggle  selection of subkey with index n.  Use 0 to
                           deselect all.

                 check     Check all selected user ids.

                 showphoto Display the selected photographic user id.

                 pref      List preferences from the selected user  ID.   This
                           shows the actual preferences, without including any
                           implied preferences.

                 showpref  More verbose preferences listing for  the  selected
                           user  ID.   This shows the preferences in effect by
                           including the implied preferences of 3DES (cipher),
                           SHA-1  (digest),  and Uncompressed (compression) if
                           they are not already  included  in  the  preference
                           list.

                 setpref string
                           Set the list of user ID preferences to string, this
                           should be a string similar to the  one  printed  by
                           "pref".  Using an empty string will set the default
                           preference string, using  "none"  will  remove  the
                           preferences.   Use "gpg --version" to get a list of
                           available algorithms.  This command  just  initial-
                           izes  an internal list and does not change anything
                           unless another command (such  as  "updpref")  which
                           changes the self-signatures is used.

                 updpref   Change  the preferences of all user IDs (or just of
                           the selected ones to the current  list  of  prefer-
                           ences.   The  timestamp of all affected self-signa-
                           tures will be advanced by one  second.   Note  that
                           while   you   can  change  the  preferences  on  an
                           attribute user ID (aka "photo ID"), GnuPG does  not
                           select keys via attribute user IDs so these prefer-
                           ences will not be used by GnuPG.

                 keyserver Set a preferred keyserver for  the  specified  user
                           ID(s).   This  allows other users to know where you
                           prefer they get your key  from.   See  --keyserver-
                           option  honor-keyserver-url  for  more  on how this
                           works.  Note that some versions  of  PGP  interpret
                           the  presence  of a keyserver URL as an instruction
                           to enable PGP/MIME mail encoding.  Setting a  value
                           of "none" removes a existing preferred keyserver.

                 toggle    Toggle between public and secret key listing.

                 save      Save all changes to the key rings and quit.

                 quit      Quit the program without updating the key rings.

                 The listing shows you the key with its secondary keys and all
                 user ids. Selected keys or  user  ids  are  indicated  by  an
                 asterisk.  The trust value is displayed with the primary key:
                 the first is the assigned owner trust and the second  is  the
                 calculated trust value.  Letters are used for the values:

                 -         No ownertrust assigned / not yet calculated.

                 e         Trust  calculation  has  failed; probably due to an
                           expired key.

                 q         Not enough information for calculation.

                 n         Never trust this key.

                 m         Marginally trusted.

                 f         Fully trusted.

                 u         Ultimately trusted.

       --sign-key name
                 Signs a public key with your secret key. This is  a  shortcut
                 version of the subcommand "sign" from --edit.

       --lsign-key name
                 Signs  a public key with your secret key but marks it as non-
                 exportable.  This is a shortcut  version  of  the  subcommand
                 "lsign" from --edit.

       --delete-key name
                 Remove  key  from  the  public keyring.  In batch mode either
                 --yes is required or the key must  be  specified  by  finger-
                 print.   This  is  a safeguard against accidental deletion of
                 multiple keys.

       --delete-secret-key name
                 Remove key from the secret and public keyring. In batch  mode
                 the key must be specified by fingerprint.

       --delete-secret-and-public-key name
                 Same  as --delete-key, but if a secret key exists, it will be
                 removed first. In batch mode the key  must  be  specified  by
                 fingerprint.

       --gen-revoke name
                 Generate  a  revocation  certificate for the complete key. To
                 revoke a subkey or a signature, use the --edit command.

       --desig-revoke name
                 Generate a designated revocation certificate for a key.  This
                 allows  a  user  (with  the  permission  of the keyholder) to
                 revoke someone else’s key.

       --export [names]
                 Either export all keys from all  keyrings  (default  keyrings
                 and  those  registered  via option --keyring), or if at least
                 one name is given, those of the given name. The  new  keyring
                 is  written  to stdout or to the file given with option "out-
                 put".  Use together with --armor to mail those keys.

       --send-keys [names]
                 Same as --export but sends the keys to a  keyserver.   Option
                 --keyserver  must be used to give the name of this keyserver.
                 Don’t send your complete keyring to a keyserver - select only
                 those keys which are new or changed by you.

       --export-secret-keys [names]

       --export-secret-subkeys [names]
                 Same  as --export, but exports the secret keys instead.  This
                 is normally not very useful and a security risk.  The  second
                 form  of  the  command has the special property to render the
                 secret part of the primary key useless; this is a GNU  exten-
                 sion to OpenPGP and other implementations can not be expected
                 to successfully import such a key.

                 See the option --simple-sk-checksum if  you  want  to  import
                 such an exported key with an older OpenPGP implementation.

       --import [files]

       --fast-import [files]
                 Import/merge  keys.  This adds the given keys to the keyring.
                 The fast version is currently just a synonym.

                 There are a few other options which control how this  command
                 works.   Most  notable  here is the --keyserver-option merge-
                 only option which does not insert new keys but does only  the
                 merging of new signatures, user-IDs and subkeys.

       --recv-keys key IDs
                 Import  the  keys  with  the  given key IDs from a keyserver.
                 Option --keyserver must be used to give the name of this key-
                 server.

       --refresh-keys [key IDs]
                 Request  updates from a keyserver for keys that already exist
                 on the local keyring.  This is useful for updating a key with
                 the  latest  signatures, user IDs, etc.  Calling this with no
                 arguments will refresh the  entire  keyring.   Option  --key-
                 server must be used to give the name of the keyserver for all
                 keys that do not have preferred keyservers  set  (see  --key-
                 server-option honor-keyserver-url).

       --search-keys [names]
                 Search  the  keyserver  for  the given names.  Multiple names
                 given here will be  joined  together  to  create  the  search
                 string for the keyserver.  Option --keyserver must be used to
                 give the name of this keyserver.

       --update-trustdb
                 Do trust database maintenance.  This  command  iterates  over
                 all  keys and builds the Web of Trust. This is an interactive
                 command because it may have to ask for the "ownertrust"  val-
                 ues  for keys.  The user has to give an estimation of how far
                 she trusts the owner of the displayed key to  correctly  cer-
                 tify  (sign)  other keys.  GnuPG only asks for the ownertrust
                 value if it has not yet been assigned to a  key.   Using  the
                 --edit-key  menu,  the  assigned  value can be changed at any
                 time.

       --check-trustdb
                 Do trust database maintenance without user interaction.  From
                 time  to  time  the  trust  database  must be updated so that
                 expired keys or signatures and the resulting changes  in  the
                 Web  of Trust can be tracked.  Normally, GnuPG will calculate
                 when this is required and do it  automatically  unless  --no-
                 auto-check-trustdb is set.  This command can be used to force
                 a trust database check at any time.  The processing is  iden-
                 tical  to  that  of --update-trustdb but it skips keys with a
                 not yet defined "ownertrust".

                 For use with cron jobs, this command  can  be  used  together
                 with  --batch  in which case the trust database check is done
                 only if a check is needed.  To force a run even in batch mode
                 add the option --yes.

       --export-ownertrust
                 Send  the  ownertrust  values  to stdout.  This is useful for
                 backup purposes as these values are the only ones which can’t
                 be re-created from a corrupted trust DB.

       --import-ownertrust [files]
                 Update the trustdb with the ownertrust values stored in files
                 (or stdin if not given); existing values will be overwritten.

       --rebuild-keydb-caches
                 When updating from version 1.0.6 to 1.0.7 this command should
                 be used to create signature caches in the keyring.  It  might
                 be handy in other situations too.

       --print-md algo [files]

       --print-mds [files]
                 Print message digest of algorithm ALGO for all given files or
                 stdin.  With the second form (or a deprecated  "*"  as  algo)
                 digests for all available algorithms are printed.

       --gen-random 0|1|2          [count]
                 Emit  COUNT random bytes of the given quality level. If count
                 is not given or zero, an endless  sequence  of  random  bytes
                 will  be  emitted.  PLEASE, don’t use this command unless you
                 know what you are doing; it may remove precious entropy  from
                 the system!

       --gen-prime mode           bits            [qbits]
                 Use  the source, Luke :-). The output format is still subject
                 to change.

       --version Print version information along  with  a  list  of  supported
                 algorithms.

       --warranty
                 Print warranty information.

       -h, --help
                 Print  usage  information.   This  is a really long list even
                 though it doesn’t list all options.  For every  option,  con-
                 sult this manual.


OPTIONS

       Long    options    can   be   put   in   an   options   file   (default
       "~/.gnupg/gpg.conf").  Short option names will not work - for  example,
       "armor"  is  a valid option for the options file, while "a" is not.  Do
       not write the 2 dashes, but simply the  name  of  the  option  and  any
       required  arguments.   Lines  with a hash (’#’) as the first non-white-
       space character are ignored.  Commands may be put in this file too, but
       that  is not generally useful as the command will execute automatically
       with every execution of gpg.

       gpg recognizes these options:

       -a, --armor
                 Create ASCII armored output.

       -o, --output file
                 Write output to file.

       --max-output n
                 This option sets a limit on the number of bytes that will  be
                 generated  when  processing  a  file.  Since OpenPGP supports
                 various levels of compression, it is possible that the plain-
                 text  of a given message may be significantly larger than the
                 original OpenPGP message.  While GnuPG  works  properly  with
                 such  messages, there is often a desire to set a maximum file
                 size that will be generated before processing  is  forced  to
                 stop  by  the  OS  limits.   Defaults  to  0, which means "no
                 limit".

       --mangle-dos-filenames

       --no-mangle-dos-filenames
                 Older version of Windows cannot handle  filenames  with  more
                 than one dot.  --mangle-dos-filenames causes GnuPG to replace
                 (rather than add to) the extension of an output  filename  to
                 avoid this problem.  This option is off by default and has no
                 effect on non-Windows platforms.

       -u, --local-user name
                 Use name as the key to sign  with.   Note  that  this  option
                 overrides --default-key.

       --default-key name
                 Use  name as the default key to sign with.  If this option is
                 not used, the default key is  the  first  key  found  in  the
                 secret  keyring.  Note that -u or --local-user overrides this
                 option.

       -r, --recipient name

                 Encrypt for user id name. If this option or  --hidden-recipi-
                 ent  is  not  specified,  GnuPG  asks  for the user-id unless
                 --default-recipient is given.

       -R, --hidden-recipient name

                 Encrypt for user id name, but hide  the  keyid  of  the  key.
                 This  option hides the receiver of the message and is a coun-
                 termeasure against  traffic  analysis.   If  this  option  or
                 --recipient  is  not  specified,  GnuPG  asks for the user-id
                 unless --default-recipient is given.

       --default-recipient name
                 Use name as default recipient if option  --recipient  is  not
                 used  and don’t ask if this is a valid one. name must be non-
                 empty.

       --default-recipient-self
                 Use the default key as default recipient if option  --recipi-
                 ent  is  not  used  and don’t ask if this is a valid one. The
                 default key is the first one from the secret keyring  or  the
                 one set with --default-key.

       --no-default-recipient
                 Reset --default-recipient and --default-recipient-self.

       --encrypt-to name
                 Same  as  --recipient but this one is intended for use in the
                 options file and may be used with  your  own  user-id  as  an
                 "encrypt-to-self".   These  keys are only used when there are
                 other recipients given either by use of --recipient or by the
                 asked user id.  No trust checking is performed for these user
                 ids and even disabled keys can be used.

       --hidden-encrypt-to name
                 Same as --hidden-recipient but this one is intended  for  use
                 in  the options file and may be used with your own user-id as
                 a hidden "encrypt-to-self".  These keys are  only  used  when
                 there are other recipients given either by use of --recipient
                 or by the asked user id.  No trust checking is performed  for
                 these user ids and even disabled keys can be used.

       --no-encrypt-to
                 Disable  the  use of all --encrypt-to and --hidden-encrypt-to
                 keys.

       -v, --verbose
                 Give more information during processing. If used  twice,  the
                 input data is listed in detail.

       -q, --quiet
                 Try to be as quiet as possible.

       -z n

       --compress-level n

       --bzip2-compress-level n
                 Set  compression  level to n for the ZIP and ZLIB compression
                 algorithms.  The default is to use  the  default  compression
                 level  of zlib (normally 6).  --bzip2-compress-level sets the
                 compression  level  for  the  BZIP2   compression   algorithm
                 (defaulting  to  6 as well).  This is a different option from
                 --compress-level since BZIP2 uses  a  significant  amount  of
                 memory  for each additional compression level.  -z sets both.
                 A value of 0 for n disables compression.

       --bzip2-decompress-lowmem
                 Use a different decompression  method  for  BZIP2  compressed
                 files.   This  alternate method uses a bit more than half the
                 memory, but also runs at half  the  speed.   This  is  useful
                 under  extreme  low  memory  circumstances  when the file was
                 originally compressed at a high --bzip2-compress-level.

       -t, --textmode

       --no-textmode
                 Treat input files as text  and  store  them  in  the  OpenPGP
                 canonical  text form with standard "CRLF" line endings.  This
                 also sets the necessary flags to inform  the  recipient  that
                 the  encrypted  or  signed data is text and may need its line
                 endings converted back to whatever  the  local  system  uses.
                 This  option  is  useful when communicating between two plat-
                 forms that have different line ending conventions  (UNIX-like
                 to  Mac,  Mac  to Windows, etc).  --no-textmode disables this
                 option, and is the default.

                 If -t (but not --textmode) is used together with armoring and
                 signing,  this  enables clearsigned messages.  This kludge is
                 needed for command-line compatibility with command-line  ver-
                 sions of PGP; normally you would use --sign or --clearsign to
                 select the type of the signature.

       -n, --dry-run
                 Don’t make any changes (this is not completely  implemented).

       -i, --interactive
                 Prompt before overwriting any files.

       --batch

       --no-batch
                 Use  batch  mode.   Never  ask, do not allow interactive com-
                 mands.  --no-batch disables this option.

       --no-tty  Make sure that the TTY (terminal) is never used for any  out-
                 put.  This option is needed in some cases because GnuPG some-
                 times prints warnings to the TTY if --batch is used.

       --yes     Assume "yes" on most questions.

       --no      Assume "no" on most questions.

       --ask-cert-level

       --no-ask-cert-level
                 When making a  key  signature,  prompt  for  a  certification
                 level.   If  this  option is not specified, the certification
                 level used is set via --default-cert-level.   See  --default-
                 cert-level  for  information  on  the specific levels and how
                 they are  used.  --no-ask-cert-level  disables  this  option.
                 This option defaults to no.

       --default-cert-level n
                 The default to use for the check level when signing a key.

                 0  means you make no particular claim as to how carefully you
                 verified the key.

                 1 means you believe the key is owned by the person who claims
                 to  own  it  but  you could not, or did not verify the key at
                 all.  This is useful for a "persona" verification, where  you
                 sign the key of a pseudonymous user.

                 2 means you did casual verification of the key.  For example,
                 this could mean that you verified that  the  key  fingerprint
                 and checked the user ID on the key against a photo ID.

                 3 means you did extensive verification of the key.  For exam-
                 ple, this could mean that you verified  the  key  fingerprint
                 with the owner of the key in person, and that you checked, by
                 means of a hard to forge document with a photo ID (such as  a
                 passport)  that the name of the key owner matches the name in
                 the user ID on the key, and finally  that  you  verified  (by
                 exchange  of email) that the email address on the key belongs
                 to the key owner.

                 Note that the examples given above for levels  2  and  3  are
                 just  that:  examples.  In the end, it is up to you to decide
                 just what "casual" and "extensive" mean to you.

                 This option defaults to 0 (no particular claim).

       --min-cert-level
                 When building the trust database,  disregard  any  signatures
                 with  a certification level below this.  Defaults to 2, which
                 disregards level 1 signatures.  Note that level 0 "no partic-
                 ular claim" signatures are always accepted.

       --trusted-key long key ID
                 Assume that the specified key (which must be given as a  full
                 8 byte key ID) is as trustworthy as one of  your  own  secret
                 keys.  This  option  is useful if you don’t want to keep your
                 secret keys (or one of them) online but still want to be able
                 to  check  the  validity of a given recipient’s or signator’s
                 key.

       --trust-model pgp|classic|always
                 Set what trust model GnuPG should follow.  The models are:


                 pgp       This is the Web of Trust combined with trust signa-
                           tures  as  used  in PGP 5.x and later.  This is the
                           default trust model.

                 classic   This is the standard Web of Trust as  used  in  PGP
                           2.x and earlier.

                 direct    Key  validity  is  set directly by the user and not
                           calculated via the Web of Trust.

                 always    Skip key validation and assume that used  keys  are
                           always  fully  trusted.   You won’t use this unless
                           you have installed some external validation scheme.
                           This  option  also suppresses the "[uncertain]" tag
                           printed with signature checks when there is no evi-
                           dence that the user ID is bound to the key.

       --always-trust
                 Identical  to  ‘--trust-model always’.  This option is depre-
                 cated.

       --keyid-format short|0xshort|long|0xlong
                 Select how to display key IDs.  "short"  is  the  traditional
                 8-character  key  ID.   "long" is the more accurate (but less
                 convenient) 16-character key ID.  Add an "0x"  to  either  to
                 include  an  "0x"  at  the  beginning  of  the  key ID, as in
                 0x99242560.

       --keyserver name
                 Use name as your keyserver.  This is the server that  --recv-
                 keys, --send-keys, and --search-keys will communicate with to
                 receive keys from, send keys to, and search for keys on.  The
                 format   of   the   name  is  a  URI:  ‘scheme:[//]keyserver-
                 name[:port]’ The scheme is the type of keyserver:  "hkp"  for
                 the  HTTP (or compatible) keyservers, "ldap" for the NAI LDAP
                 keyserver, or "mailto" for the Graff email  keyserver.   Note
                 that  your  particular  installation  of GnuPG may have other
                 keyserver types available as  well.   Keyserver  schemes  are
                 case-insensitive.

                 Most keyservers synchronize with each other, so there is gen-
                 erally no need to send keys to more  than  one  server.   The
                 keyserver  "hkp://subkeys.pgp.net"  uses  round  robin DNS to
                 give a different keyserver each time you use it.

       --keyserver-options parameters
                 This is a space or comma delimited string that gives  options
                 for  the keyserver.  Options can be prepended with a ‘no-’ to
                 give the opposite meaning.  Valid import-options  or  export-
                 options  may  be  used  here  as  well  to apply to importing
                 (--recv-key) or exporting (--send-key)  a  key  from  a  key-
                 server.   While  not  all  options are available for all key-
                 server types, some common options are:

                 include-revoked
                           When  searching  for  a  key  with   --search-keys,
                           include  keys  that  are marked on the keyserver as
                           revoked.  Note that not all keyservers  differenti-
                           ate  between  revoked  and  unrevoked keys, and for
                           such keyservers this option is  meaningless.   Note
                           also that most keyservers do not have cryptographic
                           verification of key  revocations,  and  so  turning
                           this  option  off  may result in skipping keys that
                           are incorrectly marked as revoked.  Defaults to on.

                 include-disabled
                           When   searching  for  a  key  with  --search-keys,
                           include keys that are marked on  the  keyserver  as
                           disabled.   Note  that this option is not used with
                           HKP keyservers.

                 honor-keyserver-url
                           When using --refresh-keys, if the key  in  question
                           has  a  preferred keyserver set, then use that pre-
                           ferred keyserver to refresh the key from.  Defaults
                           to yes.

                 include-subkeys
                           When  receiving a key, include subkeys as potential
                           targets.  Note that this option is  not  used  with
                           HKP  keyservers,  as they do not support retrieving
                           keys by subkey id.

                 use-temp-files
                           On most  Unix-like  platforms,  GnuPG  communicates
                           with  the keyserver helper program via pipes, which
                           is the most efficient method.  This  option  forces
                           GnuPG  to  use  temporary files to communicate.  On
                           some platforms (such as Win32 and  RISC  OS),  this
                           option is always enabled.

                 keep-temp-files
                           If  using  ‘use-temp-files’, do not delete the temp
                           files after using them.  This option is  useful  to
                           learn the keyserver communication protocol by read-
                           ing the temporary files.

                 verbose   Tell the keyserver helper program to be  more  ver-
                           bose.   This  option can be repeated multiple times
                           to increase the verbosity level.

                 timeout   Tell the keyserver helper program how long (in sec-
                           onds)  to try and perform a keyserver action before
                           giving up.  Note that performing  multiple  actions
                           at  the  same  time  uses  this  timeout  value per
                           action.  For example, when retrieving multiple keys
                           via  --recv-keys, the timeout applies separately to
                           each key retrieval, and not to the --recv-keys com-
                           mand as a whole.  Defaults to 30 seconds.

                 http-proxy[=value]
                           For  HTTP-like  keyserver schemes that (such as HKP
                           and HTTP itself), try to access the keyserver  over
                           a  proxy.  If a value is specified, use this as the
                           HTTP proxy.  If no value is specified, try  to  use
                           the value of the environment variable "http_proxy".

                 auto-key-retrieve
                           This option enables  the  automatic  retrieving  of
                           keys  from  a  keyserver  when verifying signatures
                           made by keys that are not on the local keyring.

                           Note that this option makes a "web bug" like behav-
                           ior  possible.   Keyserver  operators can see which
                           keys you request,  so  by  sending  you  a  message
                           signed by a brand new key (which you naturally will
                           not have on your local keyring), the  operator  can
                           tell  both  your  IP  address and the time when you
                           verified the signature.

       --import-options parameters
                 This is a space or comma delimited string that gives  options
                 for importing keys.  Options can be prepended with a ‘no-’ to
                 give the opposite meaning.  The options are:

                 import-local-sigs
                           Allow importing key signatures marked  as  "local".
                           This  is  not  generally  useful  unless  a  shared
                           keyring scheme is being used.  Defaults to no.

                 repair-pks-subkey-bug
                           During import, attempt to repair the damage  caused
                           by  the  PKS keyserver bug (pre version 0.9.6) that
                           mangles keys with multiple subkeys.  Note that this
                           cannot  completely  repair  the damaged key as some
                           crucial data is removed by the  keyserver,  but  it
                           does  at  least give you back one subkey.  Defaults
                           to no for regular --import and to yes for keyserver
                           --recv-keys.

                 merge-only
                           During  import, allow key updates to existing keys,
                           but do not allow  any  new  keys  to  be  imported.
                           Defaults to no.

       --export-options parameters
                 This  is a space or comma delimited string that gives options
                 for exporting keys.  Options can be prepended with a ‘no-’ to
                 give the opposite meaning.  The options are:

                 export-local-sigs
                           Allow  exporting  key signatures marked as "local".
                           This  is  not  generally  useful  unless  a  shared
                           keyring scheme is being used.  Defaults to no.

                 export-attributes
                           Include   attribute  user  IDs  (photo  IDs)  while
                           exporting.  This is useful to export keys  if  they
                           are  going  to  be  used by an OpenPGP program that
                           does not accept attribute user  IDs.   Defaults  to
                           yes.

                 export-sensitive-revkeys
                           Include  designated  revoker  information  that was
                           marked as "sensitive".  Defaults to no.

                 export-minimal
                           Export the smallest key possible.   Currently  this
                           is  done by leaving out any signatures that are not
                           self-signatures.  Defaults to no.

       --list-options parameters
                 This is a space or comma delimited string that gives  options
                 used  when listing keys and signatures (that is, --list-keys,
                 --list-sigs, --list-public-keys, --list-secret-keys, and  the
                 --edit-key functions).  Options can be prepended with a ‘no-’
                 to give the opposite meaning.  The options are:

                 show-photos
                           Causes  --list-keys,  --list-sigs,   --list-public-
                           keys,  and  --list-secret-keys to display any photo
                           IDs attached to the key.  Defaults to no.  See also
                           --photo-viewer.

                 show-policy-urls
                           Show policy URLs in the --list-sigs or --check-sigs
                           listings.  Defaults to no.

                 show-notations

                 show-std-notations

                 show-user-notations
                           Show all, IETF standard, or user-defined  signature
                           notations  in the --list-sigs or --check-sigs list-
                           ings.  Defaults to no.

                 show-keyserver-urls
                           Show any preferred keyserver URL in the --list-sigs
                           or --check-sigs listings.  Defaults to no.

                 show-uid-validity
                           Display  the calculated validity of user IDs during
                           key listings.  Defaults to no.

                 show-unusable-uids
                           Show revoked and expired user IDs in key  listings.
                           Defaults to no.

                 show-unusable-subkeys
                           Show  revoked  and expired subkeys in key listings.
                           Defaults to no.

                 show-keyring
                           Display the keyring name at the head of  key  list-
                           ings  to show which keyring a given key resides on.
                           Defaults to no.

                 show-sig-expire
                           Show signature expiration  dates  (if  any)  during
                           --list-sigs  or --check-sigs listings.  Defaults to
                           no.

                 show-sig-subpackets
                           Include signature subpackets in  the  key  listing.
                           This  option  can take an optional argument list of
                           the subpackets to list.  If no argument is  passed,
                           list  all subpackets.  Defaults to no.  This option
                           is only meaningful when using  --with-colons  along
                           with --list-sigs or --check-sigs.

       --verify-options parameters
                 This  is a space or comma delimited string that gives options
                 used when verifying signatures.   Options  can  be  prepended
                 with a ‘no-’ to give the opposite meaning.  The options are:

                 show-photos
                           Display  any  photo  IDs  present  on  the key that
                           issued the signature.  Defaults to  no.   See  also
                           --photo-viewer.

                 show-policy-urls
                           Show  policy  URLs in the signature being verified.
                           Defaults to no.

                 show-notations

                 show-std-notations

                 show-user-notations
                           Show all, IETF standard, or user-defined  signature
                           notations   in   the   signature   being  verified.
                           Defaults to IETF standard.

                 show-keyserver-urls
                           Show any preferred keyserver URL in  the  signature
                           being verified.  Defaults to no.

                 show-uid-validity
                           Display  the calculated validity of the user IDs on
                           the key that issued the signature.  Defaults to no.

                 show-unusable-uids
                           Show  revoked and expired user IDs during signature
                           verification.  Defaults to no.

       --show-photos

       --no-show-photos
                 Causes --list-keys, --list-sigs, --list-public-keys,  --list-
                 secret-keys,  and  verifying  a signature to also display the
                 photo ID attached to the key,  if  any.   See  also  --photo-
                 viewer.   These  options are deprecated.  Use ‘--list-options
                 [no-]show-photos’ and/or ‘--verify-options  [no-]show-photos’
                 instead.

       --photo-viewer string
                 This  is  the command line that should be run to view a photo
                 ID.  "%i" will be  expanded  to  a  filename  containing  the
                 photo.   "%I"  does  the  same,  except  the file will not be
                 deleted once the viewer exits.  Other flags are "%k" for  the
                 key  ID,  "%K"  for the long key ID, "%f" for the key finger-
                 print, "%t" for the extension of the image type (e.g. "jpg"),
                 "%T"  for the MIME type of the image (e.g. "image/jpeg"), and
                 "%%" for an actual percent sign.  If neither  %i  or  %I  are
                 present,  then  the  photo  will be supplied to the viewer on
                 standard input.

                 The default viewer is "xloadimage -fork -quiet -title  ’KeyID
                 0x%k’  stdin".  Note that if your image viewer program is not
                 secure, then executing it from GnuPG does not make it secure.

       --exec-path string
                 Sets  a  list  of directories to search for photo viewers and
                 keyserver helpers.  If not provided,  keyserver  helpers  use
                 the  compiled-in default directory, and photo viewers use the
                 $PATH environment variable.

       --show-keyring
                 Display the keyring name at the head of key listings to  show
                 which  keyring a given key resides on.  This option is depre-
                 cated: use ‘--list-options [no-]show-keyring’ instead.

       --keyring file
                 Add file to the current list of  keyrings.   If  file  begins
                 with  a  tilde  and  a slash, these are replaced by the $HOME
                 directory. If the filename does not contain a  slash,  it  is
                 assumed  to  be  in  the  GnuPG home directory ("~/.gnupg" if
                 --homedir or $GNUPGHOME is not used).

                 Note that this adds a keyring to the current  list.   If  the
                 intent  is  to use the specified keyring alone, use --keyring
                 along with --no-default-keyring.

       --secret-keyring file
                 Same as --keyring but for the secret keyrings.

       --primary-keyring file
                 Designate file as the primary  public  keyring.   This  means
                 that  newly  imported keys (via --import or keyserver --recv-
                 from) will go to this keyring.

       --trustdb-name file
                 Use file instead of the default trustdb.  If file begins with
                 a  tilde  and a slash, these are replaced by the $HOME direc-
                 tory. If the filename does not contain a slash, it is assumed
                 to be in the GnuPG home directory ("~/.gnupg" if --homedir or
                 $GNUPGHOME is not used).

       --homedir directory
                 Set the name of the  home  directory  to  directory  If  this
                 option  is  not  used  it defaults to "~/.gnupg". It does not
                 make sense to use this in a options file. This also overrides
                 the environment variable $GNUPGHOME.

       --display-charset name
                 Set  the  name  of the native character set.  This is used to
                 convert some informational  strings  like  user  IDs  to  the
                 proper  UTF-8  encoding.  If  this  option  is  not used, the
                 default character set is determined from the current  locale.
                 A  verbosity  level  of 3 shows the chosen set.  Valid values
                 for name are:

                 iso-8859-1
                           This is the Latin 1 set.

                 iso-8859-2
                           The Latin 2 set.

                 iso-8859-15
                           This is currently an alias for the Latin 1 set.

                 koi8-r    The usual Russian set (rfc1489).

                 utf-8     Bypass all translations and assume that the OS uses
                           native UTF-8 encoding.

       --utf8-strings

       --no-utf8-strings
                 Assume that command line arguments are given as UTF8 strings.
                 The default (--no-utf8-strings) is to assume  that  arguments
                 are  encoded  in the character set as specified by --display-
                 charset. These options affect all following arguments.   Both
                 options may be used multiple times.

       --options file
                 Read  options  from file and do not try to read them from the
                 default options file in the  homedir  (see  --homedir).  This
                 option is ignored if used in an options file.

       --no-options
                 Shortcut  for "--options /dev/null".  This option is detected
                 before an attempt to open an option file.  Using this  option
                 will also prevent the creation of a "~./gnupg" homedir.

       --load-extension name
                 Load an extension module. If name does not contain a slash it
                 is searched for in the directory configured  when  GnuPG  was
                 built (generally "/usr/local/lib/gnupg").  Extensions are not
                 generally useful anymore, and the use of this option is  dep-
                 recated.

       --debug flags
                 Set  debugging  flags.  All  flags are or-ed and flags may be
                 given in C syntax (e.g. 0x0042).

       --debug-all
                 Set all useful debugging flags.

       --debug-ccid-driver
                 Enable debug output from the included CCID driver for  smart-
                 cards.   Note that this option is only available on some sys-
                 tem.

       --enable-progress-filter
                 Enable certain PROGRESS status outputs.  This  option  allows
                 frontends  to  display a progress indicator while gpg is pro-
                 cessing larger files.  There is a slight performance overhead
                 using it.

       --status-fd n
                 Write  special  status strings to the file descriptor n.  See
                 the file DETAILS in the documentation for a listing of  them.

       --logger-fd n
                 Write log output to file descriptor n and not to stderr.

       --attribute-fd n
                 Write attribute subpackets to the file descriptor n.  This is
                 most useful for use with --status-fd, since the  status  mes-
                 sages  are needed to separate out the various subpackets from
                 the stream delivered to the file descriptor.

       --sk-comments

       --no-sk-comments
                 Include secret key  comment  packets  when  exporting  secret
                 keys.  This is a GnuPG extension to the OpenPGP standard, and
                 is off by default.  Please note that this has nothing  to  do
                 with  the comments in clear text signatures or armor headers.
                 --no-sk-comments disables this option.

       --comment string

       --no-comments
                 Use string as a comment string in clear text  signatures  and
                 ASCII  armored  messages  or keys (see --armor).  The default
                 behavior is not to use a comment string.   --comment  may  be
                 repeated  multiple  times  to  get  multiple comment strings.
                 --no-comments removes all comments.  It is  a  good  idea  to
                 keep  the  length  of a single comment below 60 characters to
                 avoid problems with mail programs wrapping such lines.  Note,
                 that  those  comment  lines, like all other header lines, are
                 not protected by the signature.

       --emit-version

       --no-emit-version
                 Force inclusion of the version string in ASCII  armored  out-
                 put.  --no-emit-version disables this option.

       --sig-notation name=value

       --cert-notation name=value

       -N, --set-notation name=value
                 Put  the name value pair into the signature as notation data.
                 name must consist only of printable characters or spaces, and
                 must contain a ’@’ character.  This is to help prevent pollu-
                 tion of the IETF reserved notation namespace.   The  --expert
                 flag  overrides the encoded in UTF8, so you should check that
                 your --display-charset is set correctly.  If you prefix  name
                 with  an  exclamation  mark  (!),  the  notation data will be
                 flagged as critical (rfc2440:5.2.3.15).  --sig-notation  sets
                 a notation for data signatures.  --cert-notation sets a nota-
                 tion for  key  signatures  (certifications).   --set-notation
                 sets both.

                 There  are  special codes that may be used in notation names.
                 "%k" will be expanded into  the  key  ID  of  the  key  being
                 signed,  "%K"  into  the long key ID of the key being signed,
                 "%f" into the fingerprint of the key being signed, "%s"  into
                 the  key  ID  of  the key making the signature, "%S" into the
                 long key ID of the key making the signature,  "%g"  into  the
                 fingerprint of the key making the signature (which might be a
                 subkey), "%p" into the fingerprint of the primary key of  the
                 key  making the signature, "%c" into the signature count from
                 the OpenPGP smartcard, and "%%" results in a single "%".  %k,
                 %K,  and  %f  are only meaningful when making a key signature
                 (certification), and %c is only  meaningful  when  using  the
                 OpenPGP smartcard.

       --show-notation

       --no-show-notation
                 Show  signature  notations in the --list-sigs or --check-sigs
                 listings as well as when verifying a signature with  a  nota-
                 tion  in  it.   These  options  are deprecated.  Use ‘--list-
                 options    [no-]show-notation’    and/or    ‘--verify-options
                 [no-]show-notation’ instead.

       --sig-policy-url string

       --cert-policy-url string

       --set-policy-url string
                 Use string as a Policy URL for signatures (rfc2440:5.2.3.19).
                 If you prefix it with an exclamation mark (!), the policy URL
                 packet  will be flagged as critical.  --sig-policy-url sets a
                 policy url for data  signatures.   --cert-policy-url  sets  a
                 policy  url  for key signatures (certifications).  --set-pol-
                 icy-url sets both.

                 The same %-expandos used for notation data are available here
                 as well.

       --show-policy-url

       --no-show-policy-url
                 Show  policy URLs in the --list-sigs or --check-sigs listings
                 as well as when verifying a signature with a  policy  URL  in
                 it.   These  options  are  deprecated.   Use  ‘--list-options
                 [no-]show-policy-url’ and/or ‘--verify-options [no-]show-pol-
                 icy-url’ instead.

       --sig-keyserver-url string
                 Use  string as a preferred keyserver URL for data signatures.
                 If you prefix it with an exclamation mark, the keyserver  URL
                 packet will be flagged as critical.

                 The same %-expandos used for notation data are available here
                 as well.

       --set-filename string
                 Use string as the filename which is stored  inside  messages.
                 This  overrides the default, which is to use the actual file-
                 name of the file being encrypted.

       --for-your-eyes-only

       --no-for-your-eyes-only
                 Set the ‘for your eyes  only’  flag  in  the  message.   This
                 causes  GnuPG  to refuse to save the file unless the --output
                 option is given, and PGP to use the "secure  viewer"  with  a
                 Tempest-resistant  font  to display the message.  This option
                 overrides --set-filename.   --no-for-your-eyes-only  disables
                 this option.

       --use-embedded-filename

       --no-use-embedded-filename
                 Try  to  create  a  file with a name as embedded in the data.
                 This can be a dangerous option  as  it  allows  to  overwrite
                 files.  Defaults to no.

       --completes-needed n
                 Number  of  completely  trusted  users to introduce a new key
                 signer (defaults to 1).

       --marginals-needed n
                 Number of marginally trusted users to  introduce  a  new  key
                 signer (defaults to 3)

       --max-cert-depth n
                 Maximum depth of a certification chain (default is 5).

       --cipher-algo name
                 Use   name  as cipher algorithm. Running the program with the
                 command --version yields a list of supported  algorithms.  If
                 this  is  not  used the cipher algorithm is selected from the
                 preferences stored with the key.

       --digest-algo name
                 Use name as the message digest algorithm. Running the program
                 with  the  command --version yields a list of supported algo-
                 rithms.

       --compress-algo name
                 Use compression algorithm name.  "zlib" is RFC-1950 ZLIB com-
                 pression.  "zip" is RFC-1951 ZIP compression which is used by
                 PGP.  "bzip2" is a more modern compression  scheme  that  can
                 compress some things better than zip or zlib, but at the cost
                 of more memory used  during  compression  and  decompression.
                 "uncompressed"  or  "none"  disables  compression.   If  this
                 option is not used, the default behavior is  to  examine  the
                 recipient key preferences to see which algorithms the recipi-
                 ent supports.  If all else fails, ZIP  is  used  for  maximum
                 compatibility.

                 ZLIB  may  give  better  compression results than ZIP, as the
                 compression window size is not limited to 8k.  BZIP2 may give
                 even  better  compression  results  than that, but will use a
                 significantly larger amount of memory while  compressing  and
                 decompressing.   This may be significant in low memory situa-
                 tions.  Note, however, that PGP (all versions) only  supports
                 ZIP  compression.   Using  any  algorithm  other  than ZIP or
                 "none" will make the message unreadable with PGP.

       --cert-digest-algo name
                 Use name as the message digest algorithm used when signing  a
                 key.  Running the program with the command --version yields a
                 list of supported algorithms.  Be aware that if you choose an
                 algorithm  that  GnuPG supports but other OpenPGP implementa-
                 tions do not, then some users will not be able to use the key
                 signatures you make, or quite possibly your entire key.

       --s2k-cipher-algo name
                 Use name as the cipher algorithm used to protect secret keys.
                 The default cipher is CAST5.  This cipher is  also  used  for
                 conventional  encryption if --personal-cipher-preferences and
                 --cipher-algo is not given.

       --s2k-digest-algo name
                 Use  name  as  the  digest  algorithm  used  to  mangle   the
                 passphrases.  The default algorithm is SHA-1.

       --s2k-mode n
                 Selects  how  passphrases  are  mangled.  If  n  is 0 a plain
                 passphrase (which is not recommended) will be used, a 1  adds
                 a  salt  to the passphrase and a 3 (the default) iterates the
                 whole process a couple of times.  Unless --rfc1991  is  used,
                 this mode is also used for conventional encryption.

       --simple-sk-checksum
                 Secret  keys  are integrity protected by using a SHA-1 check-
                 sum.  This method is part of the  upcoming  enhanced  OpenPGP
                 specification  but  GnuPG already uses it as a countermeasure
                 against certain attacks.  Old applications  don’t  understand
                 this new format, so this option may be used to switch back to
                 the old behaviour.  Using this option bears a security  risk.
                 Note that using this option only takes effect when the secret
                 key is encrypted - the simplest way to make this happen is to
                 change  the  passphrase  on  the key (even changing it to the
                 same value is acceptable).

       --disable-cipher-algo name
                 Never allow the use of name as cipher algorithm.   The  given
                 name  will  not  be  checked so that a later loaded algorithm
                 will still get disabled.

       --disable-pubkey-algo name
                 Never allow the use of name as  public  key  algorithm.   The
                 given  name  will not be checked so that a later loaded algo-
                 rithm will still get disabled.

       --no-sig-cache
                 Do not cache  the  verification  status  of  key  signatures.
                 Caching  gives  a  much  better  performance in key listings.
                 However, if you suspect that your public keyring is not  save
                 against  write modifications, you can use this option to dis-
                 able the caching.  It probably does not make sense to disable
                 it because all kind of damage can be done if someone else has
                 write access to your public keyring.

       --no-sig-create-check
                 GnuPG normally verifies each signature right  after  creation
                 to protect against bugs and hardware malfunctions which could
                 leak out bits from the secret key.  This  extra  verification
                 needs some time (about 115% for DSA keys), and so this option
                 can be used to disable it.  However, due to the fact that the
                 signature creation needs manual interaction, this performance
                 penalty does not matter in most settings.

       --auto-check-trustdb

       --no-auto-check-trustdb
                 If GnuPG feels that its information about the  Web  of  Trust
                 has  to be updated, it automatically runs the --check-trustdb
                 command internally.  This may be a  time  consuming  process.
                 --no-auto-check-trustdb disables this option.

       --throw-keyids

       --no-throw-keyids
                 Do  not put the recipient keyid into encrypted packets.  This
                 option hides the receiver of the message and is a countermea-
                 sure  against traffic analysis.  It may slow down the decryp-
                 tion process because all available  secret  keys  are  tried.
                 --no-throw-keyids disables this option.

       --not-dash-escaped
                 This  option  changes the behavior of cleartext signatures so
                 that they can be used for patch files. You  should  not  send
                 such  an  armored  file via email because all spaces and line
                 endings are hashed too.  You can not use this option for data
                 which  has  5  dashes at the beginning of a line, patch files
                 don’t have this. A special  armor  header  line  tells  GnuPG
                 about this cleartext signature option.

       --escape-from-lines

       --no-escape-from-lines
                 Because  some  mailers  change lines starting with "From " to
                 ">From " it is good to handle such lines  in  a  special  way
                 when creating cleartext signatures to prevent the mail system
                 from breaking the signature.  Note that all  other  PGP  ver-
                 sions  do it this way too.  Enabled by default.  --no-escape-
                 from-lines disables this option.

       --passphrase-fd n
                 Read the passphrase from file descriptor n. If you use 0  for
                 n,  the passphrase will be read from stdin.  This can only be
                 used if only one passphrase  is  supplied.   Don’t  use  this
                 option if you can avoid it.

       --command-fd n
                 This  is  a  replacement for the deprecated shared-memory IPC
                 mode.  If this option is enabled, user input on questions  is
                 not expected from the TTY but from the given file descriptor.
                 It should be used together with  --status-fd.  See  the  file
                 doc/DETAILS  in the source distribution for details on how to
                 use it.

       --use-agent

       --no-use-agent
                 Try to use the GnuPG-Agent. Please note that  this  agent  is
                 still under development.  With this option, GnuPG first tries
                 to connect to the agent before  it  asks  for  a  passphrase.
                 --no-use-agent disables this option.

       --gpg-agent-info
                 Override    the    value    of   the   environment   variable
                 GPG_AGENT_INFO.  This is only used when --use-agent has  been
                 given

       Compliance options
                 These  options  control what GnuPG is compliant to.  Only one
                 of these options may be active at  a  time.   Note  that  the
                 default  setting  of  this  is nearly always the correct one.
                 See the INTEROPERABILITY WITH OTHER OPENPGP PROGRAMS  section
                 below before using one of these options.

                 --gnupg   Use  standard  GnuPG behavior.  This is essentially
                           OpenPGP behavior (see  --openpgp),  but  with  some
                           additional  workarounds  for  common  compatibility
                           problems in different versions of PGP.  This is the
                           default  option, so it is not generally needed, but
                           it may be useful to override a different compliance
                           option in the gpg.conf file.

                 --openpgp Reset  all  packet,  cipher  and  digest options to
                           strict OpenPGP behavior.  Use this option to  reset
                           all   previous  options  like  --rfc1991,  --force-
                           v3-sigs, --s2k-*, --cipher-algo, --digest-algo  and
                           --compress-algo  to  OpenPGP compliant values.  All
                           PGP workarounds are disabled.

                 --rfc2440 Reset all packet,  cipher  and  digest  options  to
                           strict  RFC-2440  behavior.  Note that this is cur-
                           rently the same thing as --openpgp.

                 --rfc1991 Try to be more RFC-1991 (PGP 2.x) compliant.

                 --pgp2    Set up all options to be as PGP  2.x  compliant  as
                           possible,  and  warn  if  an  action is taken (e.g.
                           encrypting to a non-RSA key)  that  will  create  a
                           message  that  PGP  2.x will not be able to handle.
                           Note that ‘PGP 2.x’ here  means  ‘MIT  PGP  2.6.2’.
                           There  are other versions of PGP 2.x available, but
                           the MIT release is a good common baseline.

                           This option implies ‘--rfc1991 --disable-mdc  --no-
                           force-v4-certs  --no-sk-comment --escape-from-lines
                           --force-v3-sigs --no-ask-sig-expire  --no-ask-cert-
                           expire  --cipher-algo IDEA --digest-algo MD5 --com-
                           press-algo 1’.  It also  disables  --textmode  when
                           encrypting.

                 --pgp6    Set up all options to be as PGP 6 compliant as pos-
                           sible.  This restricts you to the ciphers IDEA  (if
                           the IDEA plugin is installed), 3DES, and CAST5, the
                           hashes MD5, SHA1 and RIPEMD160, and the compression
                           algorithms   none  and  ZIP.   This  also  disables
                           --throw-keyids, and making signatures with  signing
                           subkeys  as  PGP  6  does not understand signatures
                           made by signing subkeys.

                           This option implies ‘--disable-mdc  --no-sk-comment
                           --escape-from-lines  --force-v3-sigs  --no-ask-sig-
                           expire’

                 --pgp7    Set up all options to be as PGP 7 compliant as pos-
                           sible.   This  is  identical  to --pgp6 except that
                           MDCs are not disabled, and the  list  of  allowable
                           ciphers  is expanded to add AES128, AES192, AES256,
                           and TWOFISH.

                 --pgp8    Set up all options to be as PGP 8 compliant as pos-
                           sible.   PGP 8 is a lot closer to the OpenPGP stan-
                           dard than previous versions of  PGP,  so  all  this
                           does  is  disable  --throw-keyids and set --escape-
                           from-lines.  All algorithms are allowed except  for
                           the SHA384 and SHA512 digests.

       --force-v3-sigs

       --no-force-v3-sigs
                 OpenPGP states that an implementation should generate v4 sig-
                 natures but PGP versions 5 through 7 only recognize v4 signa-
                 tures  on key material.  This option forces v3 signatures for
                 signatures on data.  Note that this option  overrides  --ask-
                 sig-expire,  as  v3  signatures cannot have expiration dates.
                 --no-force-v3-sigs disables this option.

       --force-v4-certs

       --no-force-v4-certs
                 Always use v4 key signatures even on v3  keys.   This  option
                 also  changes the default hash algorithm for v3 RSA keys from
                 MD5 to SHA-1.  --no-force-v4-certs disables this option.

       --force-mdc
                 Force the use of encryption  with  a  modification  detection
                 code.  This is always used with the newer ciphers (those with
                 a blocksize greater than 64 bits), or if all of the recipient
                 keys indicate MDC support in their feature flags.

       --disable-mdc
                 Disable  the  use  of  the modification detection code.  Note
                 that by using this option, the encrypted message becomes vul-
                 nerable to a message modification attack.

       --allow-non-selfsigned-uid

       --no-allow-non-selfsigned-uid
                 Allow  the import and use of keys with user IDs which are not
                 self-signed.  This is not recommended, as a  non  self-signed
                 user  ID  is trivial to forge.  --no-allow-non-selfsigned-uid
                 disables.

       --allow-freeform-uid
                 Disable all checks on the form of the user ID while  generat-
                 ing  a new one.  This option should only be used in very spe-
                 cial environments as it does not ensure the de-facto standard
                 format of user IDs.

       --ignore-time-conflict
                 GnuPG  normally  checks  that  the timestamps associated with
                 keys and signatures have plausible  values.   However,  some-
                 times a signature seems to be older than the key due to clock
                 problems.  This option makes these  checks  just  a  warning.
                 See also --ignore-valid-from for timestamp issues on subkeys.

       --ignore-valid-from
                 GnuPG normally does not select and use subkeys created in the
                 future.   This  option  allows  the use of such keys and thus
                 exhibits the pre-1.0.7 behaviour.  You should  not  use  this
                 option  unless  you  there  is  some clock problem.  See also
                 --ignore-time-conflict for timestamp issues with  signatures.

       --ignore-crc-error
                 The  ASCII armor used by OpenPGP is protected by a CRC check-
                 sum against transmission errors.  Occasionally the  CRC  gets
                 mangled  somewhere on the transmission channel but the actual
                 content (which is protected by the OpenPGP  protocol  anyway)
                 is  still  okay.   This  option  allows  GnuPG  to ignore CRC
                 errors.

       --ignore-mdc-error
                 This option changes a MDC integrity protection failure into a
                 warning.   This  can be useful if a message is partially cor-
                 rupt, but it is necessary to get as much data as possible out
                 of the corrupt message.  However, be aware that a MDC protec-
                 tion failure may also mean that the message was tampered with
                 intentionally by an attacker.

       --lock-once
                 Lock  the databases the first time a lock is requested and do
                 not release the lock until the process terminates.

       --lock-multiple
                 Release the locks every time a lock is no longer needed.  Use
                 this to override a previous --lock-once from a config file.

       --lock-never
                 Disable locking entirely.  This option should be used only in
                 very special environments, where it can be assured that  only
                 one process is accessing those files.  A bootable floppy with
                 a stand-alone  encryption  system  will  probably  use  this.
                 Improper  usage  of this option may lead to data and key cor-
                 ruption.

       --no-random-seed-file
                 GnuPG uses a file to store  its  internal  random  pool  over
                 invocations.   This  makes  random generation faster; however
                 sometimes write operations are not desired.  This option  can
                 be used to achieve that with the cost of slower random gener-
                 ation.

       --no-verbose
                 Reset verbose level to 0.

       --no-greeting
                 Suppress the initial copyright message.

       --no-secmem-warning
                 Suppress the warning about "using insecure memory".

       --no-permission-warning
                 Suppress the warning about unsafe  file  and  home  directory
                 (--homedir)  permissions.   Note  that  the permission checks
                 that GnuPG performs are not intended to be authoritative, but
                 rather they simply warn about certain common permission prob-
                 lems.  Do not assume that the lack of a  warning  means  that
                 your system is secure.

                 Note that the warning for unsafe --homedir permissions cannot
                 be supressed in the gpg.conf file, as  this  would  allow  an
                 attacker  to  place an unsafe gpg.conf file in place, and use
                 this file to supress warnings about  itself.   The  --homedir
                 permissions  warning  may  only  be  supressed on the command
                 line.

       --no-mdc-warning
                 Suppress the warning about missing MDC integrity  protection.

       --require-secmem

       --no-require-secmem
                 Refuse to run if GnuPG cannot get secure memory.  Defaults to
                 no (i.e. run, but give a warning).

       --no-armor
                 Assume the input data is not in ASCII armored format.

       --no-default-keyring
                 Do not add the default keyrings  to  the  list  of  keyrings.
                 Note  that GnuPG will not operate without any keyrings, so if
                 you use this option and do not provide alternate keyrings via
                 --keyring  or --secret-keyring, then GnuPG will still use the
                 default public or secret keyrings.

       --skip-verify
                 Skip the signature verification step.  This may  be  used  to
                 make  the  decryption faster if the signature verification is
                 not needed.

       --with-colons
                 Print key listings delimited by colons.  Note that the output
                 will  be encoded in UTF-8 regardless of any --display-charset
                 setting.  This format is useful when  GnuPG  is  called  from
                 scripts  and  other  programs as it is easily machine parsed.
                 The details  of  this  format  are  documented  in  the  file
                 doc/DETAILS,  which is included in the GnuPG source distribu-
                 tion.

       --with-key-data
                 Print key listings delimited by colons  (like  --with-colons)
                 and print the public key data.

       --with-fingerprint
                 Same as the command --fingerprint but changes only the format
                 of the output and may be used together with another  command.

       --fast-list-mode
                 Changes  the output of the list commands to work faster; this
                 is achieved by leaving some parts empty.   Some  applications
                 don’t need the user ID and the trust information given in the
                 listings.  By using this options they can get a faster  list-
                 ing.  The exact behaviour of this option may change in future
                 versions.

       --fixed-list-mode
                 Do not merge primary user ID and primary key in  --with-colon
                 listing  mode  and  print  all  timestamps  as  seconds since
                 1970-01-01.

       --list-only
                 Changes the behaviour of some commands.  This is like  --dry-
                 run  but  different  in  some  cases.   The  semantic of this
                 command may be extended in the  future.   Currently  it  only
                 skips the actual decryption pass and therefore enables a fast
                 listing of the encryption keys.

       --no-literal
                 This is not for normal use.  Use the source to see  for  what
                 it might be useful.

       --set-filesize
                 This  is  not for normal use.  Use the source to see for what
                 it might be useful.

       --show-session-key
                 Display the session key used for one message. See --override-
                 session-key for the counterpart of this option.

                 We  think  that  Key  Escrow is a Bad Thing; however the user
                 should have the freedom to decide whether to go to prison  or
                 to reveal the content of one specific message without compro-
                 mising all messages ever encrypted for one secret key.  DON’T
                 USE IT UNLESS YOU ARE REALLY FORCED TO DO SO.

       --override-session-key string
                 Don’t  use  the  public  key but the session key string.  The
                 format of this string is the  same  as  the  one  printed  by
                 --show-session-key.   This  option  is  normally not used but
                 comes handy in case someone forces you to reveal the  content
                 of  an  encrypted  message; using this option you can do this
                 without handing out the secret key.

       --ask-sig-expire

       --no-ask-sig-expire
                 When making a data signature, prompt for an expiration  time.
                 If  this  option  is  not  specified,  the expiration time is
                 "never".  --no-ask-sig-expire disables this option.

       --ask-cert-expire

       --no-ask-cert-expire
                 When making a key signature, prompt for an  expiration  time.
                 If  this  option  is  not  specified,  the expiration time is
                 "never".  --no-ask-cert-expire disables this option.

       --expert

       --no-expert
                 Allow the user to do certain nonsensical  or  "silly"  things
                 like  signing  an  expired  or revoked key, or certain poten-
                 tially incompatible things like generating unusual key types.
                 This also disables certain warning messages about potentially
                 incompatible actions.  As the name implies,  this  option  is
                 for experts only.  If you don’t fully understand the implica-
                 tions of what it allows you to do,  leave  this  off.   --no-
                 expert disables this option.

       --allow-secret-key-import
                 This is an obsolete option and is not used anywhere.

       --try-all-secrets
                 Don’t look at the key ID as stored in the message but try all
                 secret keys in turn to find the right  decryption  key.  This
                 option  forces  the behaviour as used by anonymous recipients
                 (created by using --throw-keyids) and  might  come  handy  in
                 case where an encrypted message contains a bogus key ID.

       --enable-special-filenames
                 This  options  enables  a mode in which filenames of the form
                 -&n, where n is a non-negative decimal number, refer  to  the
                 file descriptor n and not to a file with that name.

       --no-expensive-trust-checks
                 Experimental use only.

       --group name=value1 [value2 value3 ...]
                 Sets  up  a named group, which is similar to aliases in email
                 programs.  Any time the group name  is  a  recipient  (-r  or
                 --recipient),  it  will  be expanded to the values specified.
                 Multiple groups with the same name are  automatically  merged
                 into a single group.

                 The  values are key IDs or fingerprints, but any key descrip-
                 tion is accepted.  Note that a value with spaces in  it  will
                 be  treated as two different values.  Note also there is only
                 one level of expansion - you cannot make an group that points
                 to another group.  When used from the command line, it may be
                 necessary to quote the argument to this option to prevent the
                 shell from treating it as multiple arguments.

       --ungroup name
                 Remove a given entry from the --group list.

       --no-groups
                 Remove all entries from the --group list.

       --preserve-permissions
                 Don’t change the permissions of a secret keyring back to user
                 read/write only.  Use this option only  if  you  really  know
                 what you are doing.

       --personal-cipher-preferences string
                 Set  the  list of personal cipher preferences to string, this
                 list should be a string similar to the  one  printed  by  the
                 command  "pref"  in  the  edit menu.  This allows the user to
                 factor in their own preferred algorithms when algorithms  are
                 chosen via recipient key preferences.  The most highly ranked
                 cipher in this list is also used for the --symmetric  encryp-
                 tion command.

       --personal-digest-preferences string
                 Set  the  list of personal digest preferences to string, this
                 list should be a string similar to the  one  printed  by  the
                 command  "pref"  in  the  edit menu.  This allows the user to
                 factor in their own preferred algorithms when algorithms  are
                 chosen via recipient key preferences.  The most highly ranked
                 digest algorithm in this list is algo used when signing with-
                 out  encryption  (e.g.  --clearsign  or --sign).  The default
                 value is SHA-1.

       --personal-compress-preferences string
                 Set the list of personal compression preferences  to  string,
                 this  list  should  be a string similar to the one printed by
                 the command "pref" in the edit menu.  This allows the user to
                 factor  in their own preferred algorithms when algorithms are
                 chosen via recipient key preferences.  The most highly ranked
                 algorithm in this list is also used when there are no recipi-
                 ent keys to consider (e.g. --symmetric).

       --default-preference-list string
                 Set the list of default  preferences  to  string,  this  list
                 should  be a string similar to the one printed by the command
                 "pref" in the edit menu.  This affects  both  key  generation
                 and "updpref" in the edit menu.

       --list-config [names]
                 Display  various  internal configuration parameters of GnuPG.
                 This option is intended for external programs that call GnuPG
                 to  perform tasks, and is thus not generally useful.  See the
                 file doc/DETAILS in the source distribution for  the  details
                 of which configuration items may be listed.  --list-config is
                 only usable with --with-colons set.


How to specify a user ID

       There are different ways to specify a user ID to GnuPG; here  are  some
       examples:




       234567C4

       0F34E556E

       01347A56A

       0xAB123456
                 Here the key ID is given in the usual short form.

       234AABBCC34567C4

       0F323456784E56EAB

       01AB3FED1347A5612

       0x234AABBCC34567C4
                 Here  the key ID is given in the long form as used by OpenPGP
                 (you can get the long key ID using the option --with-colons).

       1234343434343434C434343434343434

       123434343434343C3434343434343734349A3434

       0E12343434343434343434EAB3484343434343434

       0xE12343434343434343434EAB3484343434343434
                 The  best way to specify a key ID is by using the fingerprint
                 of the key.  This avoids any ambiguities in case  that  there
                 are  duplicated  key  IDs (which are really rare for the long
                 key IDs).

       =Heinrich Heine <heinrichh@uni-duesseldorf.de>
                 Using an exact to match string.   The  equal  sign  indicates
                 this.

       <heinrichh@uni-duesseldorf.de>
                 Using  the  email  address part which must match exactly. The
                 left angle bracket indicates this email address mode.

       +Heinrich Heine duesseldorf
                 All words must match exactly (not  case  sensitive)  but  can
                 appear  in any order in the user ID.  Words are any sequences
                 of letters, digits, the underscore and  all  characters  with
                 bit 7 set.

       Heine

       *Heine    By  case insensitive substring matching.  This is the default
                 mode but applications may want to explicitly indicate this by
                 putting the asterisk in front.

       Note  that you can append an exclamation mark (!) to key IDs or finger-
       prints.  This flag tells GnuPG to use the  specified  primary  or  sec-
       ondary  key and not to try and calculate which primary or secondary key
       to use.



RETURN VALUE

       The program returns 0 if everything was fine, 1 if at least a signature
       was bad, and other error codes for fatal errors.



EXAMPLES

       gpg -se -r Bob file
                 sign and encrypt for user Bob

       gpg --clearsign file
                 make a clear text signature

       gpg -sb  file
                 make a detached signature

       gpg --list-keys  user_ID
                 show keys

       gpg --fingerprint  user_ID
                 show fingerprint

       gpg --verify  pgpfile

       gpg --verify  sigfile [files]
                 Verify  the signature of the file but do not output the data.
                 The second form is used for detached signatures,  where  sig-
                 file  is  the  detached  signature  (either  ASCII armored or
                 binary) and [files] are the  signed  data;  if  this  is  not
                 given,  the  name of the file holding the signed data is con-
                 structed by cutting off the extension (".asc" or  ".sig")  of
                 sigfile or by asking the user for the filename.


ENVIRONMENT

       HOME      Used to locate the default home directory.

       GNUPGHOME If set directory used instead of "~/.gnupg".

       GPG_AGENT_INFO
                 Used  to  locate the gpg-agent; only honored when --use-agent
                 is set.  The value consists of 3 colon delimited fields:  The
                 first  is  the path to the Unix Domain Socket, the second the
                 PID of the gpg-agent and the protocol version which should be
                 set  to  1.   When starting the gpg-agent as described in its
                 documentation, this variable is set  to  the  correct  value.
                 The option --gpg-agent-info can be used to override it.

       http_proxy
                 Only  honored  when  the keyserver-option honor-http-proxy is
                 set.

       COLUMNS

       LINES     Used to size some displays to the full size of the screen.


FILES

       ~/.gnupg/secring.gpg
                 The secret keyring

       ~/.gnupg/secring.gpg.lock
                 and the lock file

       ~/.gnupg/pubring.gpg
                 The public keyring

       ~/.gnupg/pubring.gpg.lock
                 and the lock file

       ~/.gnupg/trustdb.gpg
                 The trust database

       ~/.gnupg/trustdb.gpg.lock
                 and the lock file

       ~/.gnupg/random_seed
                 used to preserve the internal random pool

       ~/.gnupg/gpg.conf
                 Default configuration file

       ~/.gnupg/options
                 Old style configuration file; only used when gpg.conf is  not
                 found

       /usr[/local]/share/gnupg/options.skel
                 Skeleton options file

       /usr[/local]/lib/gnupg/
                 Default location for extensions


WARNINGS

       Use  a *good* password for your user account and a *good* passphrase to
       protect your secret key.  This passphrase is the weakest  part  of  the
       whole system.  Programs to do dictionary attacks on your secret keyring
       are very easy to write and  so  you  should  protect  your  "~/.gnupg/"
       directory very well.

       Keep  in mind that, if this program is used over a network (telnet), it
       is *very* easy to spy out your passphrase!

       If you are going to verify detached signatures, make sure that the pro-
       gram  knows about it; either give both filenames on the command line or
       use - to specify stdin.


INTEROPERABILITY WITH OTHER OPENPGP PROGRAMS

       GnuPG tries to be a very flexible implementation of the  OpenPGP  stan-
       dard.   In  particular,  GnuPG implements many of the optional parts of
       the standard, such as the SHA-512 hash, and the ZLIB and BZIP2 compres-
       sion algorithms.  It is important to be aware that not all OpenPGP pro-
       grams implement these optional algorithms and that by forcing their use
       via  the  --cipher-algo,  --digest-algo,  --cert-digest-algo, or --com-
       press-algo options in GnuPG, it is possible to create a perfectly valid
       OpenPGP message, but one that cannot be read by the intended recipient.

       There are dozens of variations of OpenPGP programs available, and  each
       supports a slightly different subset of these optional algorithms.  For
       example, until recently, no (unhacked) version  of  PGP  supported  the
       BLOWFISH  cipher  algorithm.  A message using BLOWFISH simply could not
       be read by a PGP user.  By default, GnuPG  uses  the  standard  OpenPGP
       preferences  system that will always do the right thing and create mes-
       sages that are usable by all recipients, regardless  of  which  OpenPGP
       program  they  use.  Only override this safe default if you really know
       what you are doing.

       If you absolutely must override the safe default, or if the preferences
       on  a  given  key  are  invalid for some reason, you are far better off
       using the --pgp6, --pgp7, or --pgp8 options.  These options are safe as
       they  do  not  force any particular algorithms in violation of OpenPGP,
       but rather reduce the available algorithms to a "PGP-safe" list.


BUGS

       On many systems this program should be installed as setuid(root).  This
       is  necessary  to lock memory pages.  Locking memory pages prevents the
       operating  system  from  writing  memory  pages  (which   may   contain
       passphrases  or other sensitive material) to disk.  If you get no warn-
       ing message about insecure memory your operating system supports  lock-
       ing  without  being root.  The program drops root privileges as soon as
       locked memory is allocated.



                                                                        gpg(1)

Man(1) output converted with man2html