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 avail
able. For a more verbose documentation get the GNU Pri
vacy Handbook (GPH), which is available at
http://www.gnupg.org/gph/ . You will find a list of HOWTO
documents at http://www.gnupg.org/docs.html .
COMMANDS
gpg recognizes these commands:
-s, --sign
Make a signature. This command may be combined
with --encrypt.
--clearsign
Make a clear text signature.
-b, --detach-sign
Make a detached signature.
-e, --encrypt
Encrypt data. This option may be combined with
--sign.
-c, --symmetric
Encrypt with symmetric cipher only. This com
mand asks for 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 generating any output. With no argu
ments, the signature packet is read from stdin.
If only a sigfile is given, it may be a complete
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 sig
nature 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.
--verify-files [files]
This is a special version of the --verify com
mand which does not work with detached signa
tures. The command expects the files to be ver
ified either on the command line or reads the
filenames from stdin; each name must be on sep
arate line. The command is intended for quick
checking of many files.
--list-keys [names]
--list-public-keys [names]
List all keys from the public keyrings, or just
the ones given on the command line.
--list-secret-keys [names]
List all keys from the secret keyrings, or just
the ones given on the command line.
--list-sigs [names]
Same as --list-keys, but the signatures are
listed too.
--check-sigs [names]
Same as --list-sigs, but the signatures are ver
ified.
--fingerprint [names]
List all keys with their fingerprints. This is
the same output as --list-keys but with the
additional output of a line with the finger
print. May also be combined with --list-sigs or
--check-sigs. If this command is given twice,
the fingerprints 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 nor
mally only used interactively.
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 fingerprint 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 others.
This may be used to make keys valid
only in the local environment.
revsig Revoke a signature. GnuPG asks for
every signature which has been done by
one of the secret keys, whether a
revocation certificate should be gen
erated.
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 normally not be used
for encryption.
adduid Create an alternate user id.
deluid Delete a user id.
addkey Add a subkey to this key.
delkey Remove a subkey.
revkey Revoke a subkey.
expire Change the key expiration time. If a
key is selected, the time of this key
will be changed. With no selection
is changed.
passwd Change the passphrase of the secret
key.
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.
pref List preferences.
showpref More verbose preferences listing.
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 cal
culated trust value. Letters are used for the
values:
- No ownertrust assigned / not yet cal
culated.
e Trust calculation has failed; probably
due to an expired key.
q Not enough information for calcula
tion.
n Never trust this key.
m Marginally trusted.
f Fully trusted.
u Ultimately trusted.
--sign-key name
Sign a public key with your secret key. This is
--edit.
--lsign-key name
Sign a public key with your secret key but mark
it as non-exportable. This is a shortcut ver
sion of the subcommand "lsign" from --edit.
--trusted-key long key ID
Assume that the specified key (which must be
given as a full 8 byte key ID) is as trustwor
thy 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 recipi
ent's or signator's key.
--delete-key name
Remove key from the public keyring
--delete-secret-key name
Remove key from the secret and public keyring
--delete-secret-and-public-key name
Same as --delete-key, but if a secret key
exists, it will be removed first.
--gen-revoke
Generate a revocation certificate for the com
plete key. To revoke a subkey or a signature,
use the --edit command.
--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 "output". Use together with --armor to
mail those keys.
--send-keys [names]
Same as --export but sends the keys to a key
server. Option --keyserver must be used to give
the name of this keyserver. Don't send your com
plete keyring to a keyserver - select only those
keys which are new or changed by you.
--export-all [names]
Same as --export, but also exports keys which
are not compatible with OpenPGP.
--export-secret-keys [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
extension to OpenPGP and other implementations
can not be expected to successfully import such
a key.
--import [files]
--fast-import [files]
Import/merge keys. This adds the given keys to
the keyring. The fast version does not build
the trustdb; this can be done at any time with
the command --update-trustdb.
There are a few other options which control how
this command works. Most notable here is the
--merge-only option which does not insert new
keys but does only the merging of new signa
tures, user-IDs and subkeys. See also the
option --allow-secret-key-import.
--recv-keys key IDs
Import the keys with the given key IDs from a
HKP keyserver. Option --keyserver must be used
to give the name of this keyserver.
--export-ownertrust
List the assigned ownertrust values in ASCII
format for backup purposes.
--import-ownertrust [files]
Update the trustdb with the ownertrust values
stored in files (or stdin if not given); exist
ing values will be overwritten.
--print-md algo [files]
Print message digest of algorithm ALGO for all
given files of stdin. If "*" is used for the
algorithm, 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!
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.
OPTIONS
Long options can be put in an options file (default
"~/.gnupg/options"). Do not write the 2 dashes, but sim
ply 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 does not make sense.
gpg recognizes these options:
-a, --armor
Create ASCII armored output.
-o, --output file
Write output to file.
-u, --local-user name
Use name as the user ID to sign. This option is
silently ignored for the list commands, so that
it can be used in an options file.
--default-key name
Use name as default user ID for signatures. If
this is not used the default user ID is the
first user ID found in the secret keyring.
-r, --recipient name
Encrypt for user id name. If this option is not
specified, GnuPG asks for the user-id unless
--default-recipient is given
--default-recipient name
Use name as default recipient if option --recip
ient 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 --recipient is not used and don't ask if
first one from the secret keyring or the one set
with --default-key.
--no-default-recipient
Reset --default-recipient and --default-recipi
ent-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 recipi
ents given either by use of --recipient or by
the asked user id. No trust checking is per
formed for these user ids and even disabled keys
can be used.
--no-encrypt-to
Disable the use of all --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 Set compression level to n. A value of 0 for n
disables compression. Default is to use the
default compression level of zlib (normally 6).
-t, --textmode
Use canonical text mode. If -t (but not
--textmode) is used together with armoring and
signing, this enables clearsigned messages.
This kludge is needed for PGP compatibility;
normally you would use --sign or --clearsign to
selected 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 Use batch mode. Never ask, do not allow inter
active commands.
--no-tty Make sure that the TTY (terminal) is never used
for any output. This option is needed in some
cases because GnuPG sometimes prints warnings to
the TTY if --batch is used.
Disable batch mode. This may be of use if
--batch is enabled from an options file.
--yes Assume "yes" on most questions.
--no Assume "no" on most questions.
--always-trust
Skip key validation and assume that used keys
are always fully trusted. You won't use this
unless you have installed some external valida
tion scheme.
--keyserver name
Use name to lookup keys which are not yet in
your keyring. This is only done while verifying
messages with signatures. The option is also
required for the command --send-keys to specify
the keyserver to where the keys should be send.
All keyservers synchronize with each other - so
there is no need to send keys to more than one
server. Using the command "host -l pgp.net |
grep wwwkeys" gives you a list of keyservers.
Because there is load balancing using round-
robin DNS you may notice that you get different
key servers.
--no-auto-key-retrieve
This option disables the automatic retrieving of
keys from a keyserver while verifying signa
tures. This option allows you to keep a key
server in the options file for the --send-keys
and --recv-keys commands.
--honor-http-proxy
Try to access the keyserver over the proxy set
with the variable "http_proxy".
--keyring file
Add file to the 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 home-directory ("~/.gnupg" if --homedir is
not used). The filename may be prefixed with a
scheme:
"gnupg-ring:" is the default one.
"gnupg-gdbm:" may be used for a GDBM ring. Note
that GDBM is experimental and likely to be
removed in future versions.
--no-default-keyring.
--secret-keyring file
Same as --keyring but for the secret keyrings.
--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 envi
ronment variable "GNUPGHOME".
--charset name
Set the name of the native character set. This
is used to convert some strings to proper UTF-8
encoding. Valid values for name are:
iso-8859-1
This is the default Latin 1 set.
iso-8859-2
The Latin 2 set.
koi8-r The usual Russian set (rfc1489).
utf-8 Bypass all translations and assume
that the OS uses native UTF-8 encod
ing.
--utf8-strings
--no-utf8-strings
Assume that the arguments are already given as
UTF8 strings. The default (--no-utf8-strings)
is to assume that arguments are encoded in the
character set as specified by --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 home
dir (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.
--load-extension name
Load an extension module. If name does not con
tain a slash it is searched in
information about extensions.
--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.
--status-fd n
Write special status strings to the file
descriptor n. See the file DETAILS in the docu
mentation for a listing of them.
--logger-fd n
Write log output to file descriptor n and not to
stderr.
--no-comment
Do not write comment packets. This option
affects only the generation of secret
keys. Please note, that this has nothing to do
with the comments in clear text signatures.
--comment string
Use string as comment string in clear text sig
natures. To suppress those comment strings
entirely, use an empty string here.
--default-comment
Force to write the standard comment string in
clear text signatures. Use this to overwrite a
--comment from a config file.
--no-version
Omit the version string in clear text signa
tures.
--emit-version
Force to write the version string in clear text
signatures. Use this to overwrite a previous
--no-version from a config file.
-N, --notation-data name=value
Put the name value pair into the signature as
notation data. name must consist only of
alphanumeric characters, digits or the under
score; the first character must not be a digit.
value may be any printable string; it will be
encoded in UTF8, so you should check that your
--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).
Use string as 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.
--set-filename string
Use string as the name of file which is stored
in messages.
--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.
--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 pro
gram with the command --version yields a list of
supported algorithms. If this is not used the
cipher algorithm is selected from the prefer
ences stored with the key.
--digest-algo name
Use name as message digest algorithm. Running
the program with the command --version yields a
list of supported algorithms. Please note that
using this option may violate the OpenPGP
requirement, that a 160 bit hash is to be used
for DSA.
--s2k-cipher-algo name
Use name as the cipher algorithm used to pro
tect secret keys. The default cipher is
BLOWFISH. This cipher is also used for conven
tional encryption if --cipher-algo is not given.
--s2k-digest-algo name
Use name as the digest algorithm used to mangle
the passphrases. The default algorithm is RIPE-
MD-160. This digest algorithm is also used for
conventional encryption if --digest-algo is not
given.
Selects how passphrases are mangled. If n is 0 a
plain passphrase (which is not recommended) will
be used, a 1 (default) adds a salt to the
passphrase and a 3 iterates the whole process a
couple of times. Unless --rfc1991 is used, this
mode is also used for conventional encryption.
--compress-algo n
Use compress algorithm n. Default is 2 which is
RFC1950 compression. You may use 1 to use the
old zlib version (RFC1951) which is used by PGP.
The default algorithm may give better results
because the window size is not limited to 8K. If
this is not used the OpenPGP behavior is used,
i.e. the compression algorithm is selected from
the preferences; note, that this can't be done
if you do not encrypt the data.
--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 algo
rithm. The given name will not be checked so
that a later loaded algorithm will still get
disabled.
--no-sig-cache
Do not cache the verification status of key sig
natures. Caching gives a much better perfor
mance in key listings. However, if you suspect
that your public keyring is not save against
write modifications, you can use this option to
disable 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 hard
ware 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.
--throw-keyid
Do not put the keyid into encrypted packets.
and is a countermeasure against traffic analy
sis. It may slow down the decryption process
because all available secret keys are tried.
--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 cleart
ext signature option.
--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. All other PGP versions do it this
way too. This option is not enabled by default
because it would violate rfc2440.
--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
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.
--rfc1991 Try to be more RFC1991 (PGP 2.x) compliant.
--openpgp Reset all packet, cipher and digest options to
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 also disabled.
OpenPGP states that an implementation should
generate v4 signatures but PGP 5.x recognizes v4
signatures only on key material. This option
forces v3 signatures for signatures on data.
--force-mdc
Force the use of encryption with appended manip
ulation code. This is always used with the
newer ciphers (those with a blocksize greater
than 64 bit). This option might not be imple
mented yet.
--allow-non-selfsigned-uid
Allow the import of keys with user IDs which are
not self-signed, but have at least one signa
ture. This only allows the import - key valida
tion will fail and you have to check the valid
ity of the key my other means. This hack is
needed for some German keys generated with pgp
2.6.3in. You should really avoid using it,
because OpenPGP has better mechanics to do sepa
rate signing and encryption keys.
--allow-freeform-uid
Disable all checks on the form of the user ID
while generating a new one. This option should
only be used in very special environments as it
does not ensure the de-facto standard format of
user IDs.
--ignore-time-conflict
GnuPG normally checks that the timestamps asso
ciated with keys and signatures have plausible
values. However, sometimes a signature seems to
be older than the key due to clock problems.
This option makes these checks just a warning.
--ignore-crc-error
The ASCII armor used by OpenPG is protected by a
CRC checksum against transmission errors. Some
times it happens that the CRC gets mangled some
where on the transmission channel but the actual
content (which is anyway protected by the
OpenPGP protocol) is still okay. This option
will let gpg ignore CRC errors.
--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
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 access
ing 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 corruption.
--no-random-seed-file
GnuPG uses a file to store its internal random
pool over invocations. This makes random gener
ation faster; however sometimes write operations
are not desired. This option can be used to
achieve that with the cost of slower random gen
eration.
--no-verbose
Reset verbose level to 0.
--no-greeting
Suppress the initial copyright message but do
not enter batch mode.
--no-secmem-warning
Suppress the warning about "using insecure mem
ory".
--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.
--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.
--with-key-data
Print key listings delimited by 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
--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
listing. The exact behaviour of this option may
change in future versions.
--fixed-list-mode
Do not merge 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.
--emulate-md-encode-bug
GnuPG versions prior to 1.0.2 had a bug in the
way a signature was encoded. This options
enables a workaround by checking faulty signa
tures again with the encoding used in old ver
sions. This may only happen for ElGamal signa
tures which are not widely used.
--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 compromising all
messages ever encrypted for one secret key.
DON'T USE IT UNLESS YOU ARE REALLY FORCED TO DO
SO.
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.
--merge-only
Don't insert new keys into the keyrings while
doing an import.
--allow-secret-key-import
Allow import of secret keys. The import command
normally skips secret keys because a secret key
can otherwise be used to attack the trust calcu
lation.
--try-all-secrets
Don't look at the key ID as stored in the mes
sage but try all secret keys in turn to find the
right decryption key. This option forces the
behaviour as used by anonymous recipients (cre
ated by using --throw-keyid) and might come
handy in case where an encrypted message con
tains 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 deci
mal number, refer to the file descriptor n and
not to a file with that name.
--no-expensive-trust-checks
Experimental use only.
How to specify a user ID
There are different ways on how 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.
0F323456784E56EAB
01AB3FED1347A5612
0x234AABBCC34567C4
Here the key ID is given in the long form as
used by OpenPGP.
1234343434343434C434343434343434
123434343434343C3434343434343734349A3434
0E12343434343434343434EAB3484343434343434
0xE12343434343434343434EAB3484343434343434
The best way to specify a key ID is by using the
fingerprint of the key. This avoids any ambigu
ities 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 sensi
tive) 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.
#34 Using the Local ID. This is a very low level
method and should only be used by applications
which really need it. The hash character indi
cates this method. An application should
not assume that this is only a number.
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
fingerprints. This flag which tells GnuPG to use exactly
that primary or secondary key and don't try to figure out
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 out
put the data. The second form is used for
detached signatures, where sigfile is the
detached signature (either ASCII armored of
binary) and [files] are the signed data; if this
is not given the name of the file holding the
signed data is constructed 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".
http_proxy
Only honored when the option --honor-http-proxy
is set.
FILES
~/.gnupg/secring.gpg
The secret keyring
~/.gnupg/secring.gpg.lock
and the lock file
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/options
May contain options
/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 dic
tionary 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 program nows about it; either be giving both
filenames on the commandline or using - to specify stdin.
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 to disk. If you get no warning mes
sage about insecure memory your operating system supports
locking without being root. The program drops root privi
leges as soon as locked memory is allocated.
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