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.
Use standard GnuPG behavior. This is essentially OpenPGP behavior (see --openpgp), but with extension from the proposed update to OpenPGP and 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.
Reset all packet, cipher and digest options to strict OpenPGP behavior. This option implies --allow-old-cipher-algos. Use this option to reset all previous options like --s2k-*, --cipher-algo, --digest-algo and --compress-algo to OpenPGP compliant values. All PGP workarounds are disabled.
Reset all packet, cipher and digest options to strict RFC-4880 behavior. This option implies --allow-old-cipher-algos. Note that this is currently the same thing as --openpgp.
Reset all packet, cipher and digest options to strict according to the proposed updates of RFC-4880.
Reset all packet, cipher and digest options to strict RFC-2440 behavior. Note that by using this option encryption packets are created in a legacy mode without MDC protection. This is dangerous and should thus only be used for experiments. This option implies --allow-old-cipher-algos. See also option --ignore-mdc-error.
This option is obsolete; it is handled as an alias for --pgp7
Set up all options to be as PGP 7 compliant as possible. This allowed the ciphers IDEA, 3DES, CAST5,AES128, AES192, AES256, and TWOFISH., the hashes MD5, SHA1 and RIPEMD160, and the compression algorithms none and ZIP. This option implies --escape-from-lines and disables --throw-keyids,
Set up all options to be as PGP 8 compliant as possible. PGP 8 is a lot closer to the OpenPGP standard 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 SHA224, SHA384, and SHA512 digests.
This option can be used instead of one of the options above. Valid values for string are the above option names (without the double dash) and possibly others as shown when using "help" for value.