How these messages are mapped to the actual debugging flags is not
specified and may change with newer releases of this program. They are
however carefully selected to best aid in debugging.
n. See the file DETAILS in the documentation for a listing of them.
nand not to STDERR.
file. Note that --log-file is only implemented for GnuPG-2.
n. This is most useful for use with --status-fd, since the status messages are needed to separate out the various subpackets from the stream delivered to the file descriptor.
stringas 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 comment lines, like all other header lines, are not protected by the signature.
-N, --set-notation name=value
namemust consist only of printable characters or spaces, and must contain a '@' character in the form email@example.com (substituting the appropriate keyname and domain name, of course). This is to help prevent pollution of the IETF reserved notation namespace. The --expert flag overrides the '@' check.
valuemay be any printable string; it will be encoded in UTF8, so you should check that your --display-charset is set correctly. If you prefix
namewith an exclamation mark (!), the notation data will be flagged as critical (rfc4880:188.8.131.52). --sig-notation sets a notation for data signatures. --cert-notation sets a notation 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.
stringas a Policy URL for signatures (rfc4880:184.108.40.206). 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-policy-url sets both.
The same %-expandos used for notation data are available here as well.
stringas 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.
stringas the filename which is stored inside messages. This overrides the default, which is to use the actual filename of the file being encrypted.
nameas 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. In general, you do not want to use this option as it allows you to violate the OpenPGP standard. --personal-cipher-preferences is the safe way to accomplish the same thing.
nameas the message digest algorithm. Running the program with the command --version yields a list of supported algorithms. In general, you do not want to use this option as it allows you to violate the OpenPGP standard. --personal-digest-preferences is the safe way to accomplish the same thing.
name. "zlib" is RFC-1950 ZLIB compression. "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 recipient 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 situations. 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. In
general, you do not want to use this option as it allows you to
violate the OpenPGP standard. --personal-compress-preferences is the
safe way to accomplish the same thing.
nameas 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 implementations do not, then some users will not be able to use the key signatures you make, or quite possibly your entire key.
nameas cipher algorithm. The given name will not be checked so that a later loaded algorithm will still get disabled.
nameas public key algorithm. The given name will not be checked so that a later loaded algorithm will still get disabled.
n. Only the first line will be read 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. Note that this passphrase is only used if the option --batch has also been given. This is different from gpg.
file. Only the first line will be read from file
file. This can only be used if only one passphrase is supplied. Obviously, a passphrase stored in a file is of questionable security if other users can read this file. Don't use this option if you can avoid it. Note that this passphrase is only used if the option --batch has also been given. This is different from gpg.
stringas the passphrase. This can only be used if only one passphrase is supplied. Obviously, this is of very questionable security on a multi-user system. Don't use this option if you can avoid it. Note that this passphrase is only used if the option --batch has also been given. This is different from gpg.
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.
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.
Warning: Do not use this option unless you need it as a temporary
string. This preference list is used for new keys and becomes the default for "setpref" in the edit menu.
name. This keyserver will be used as the keyserver URL when writing a new self-signature on a key, which includes key generation and changing preferences.
 Using a little social engineering anyone who is able to decrypt the message can check whether one of the other recipients is the one he suspects.