This message is encrypted with two passwords, 'a' and 'b':
% cat hello.symmetric.asc
-----BEGIN PGP MESSAGE-----
wy4ECQMIGmAnjc97EU7p1MLrxt9q12P80Rsn8hm55jXwXYTunD3DvvI5H0eB9DiZ
wy4ECQMIGAxa4+qnCb/pIe3S0sMWSafAiYVx7ASMhtcUiWBPFiwHbQuXE/vwqbCH
0jcBcn/T5lXcDZP0aQd47LZiUL2sADwbLB/M/FkoFO+5R6Fb4yYEdme+dyaJuDgY
xysOfLbde3Nc
=8do1
-----END PGP MESSAGE-----
% gpg --list-packets hello.symmetric.asc
gpg: AES256 encrypted session key
gpg: encrypted with 2 passphrases
# off=0 ctb=c3 tag=3 hlen=2 plen=46 new-ctb
:symkey enc packet: version 4, cipher 9, s2k 3, hash 8, seskey 256 bits
salt 1A60278DCF7B114E, count 26214400 (233)
# off=48 ctb=c3 tag=3 hlen=2 plen=46 new-ctb
:symkey enc packet: version 4, cipher 9, s2k 3, hash 8, seskey 256 bits
salt 180C5AE3EAA709BF, count 26214400 (233)
# off=96 ctb=d2 tag=18 hlen=2 plen=55 new-ctb
:encrypted data packet:
length: 55
mdc_method: 2
# off=117 ctb=cb tag=11 hlen=2 plen=12 new-ctb
:literal data packet:
mode b (62), created 0, name="",
raw data: 6 bytesDecryption works with password 'a':
% gpg --decrypt hello.symmetric.asc gpg: AES256 encrypted session key gpg: encrypted with 2 passphrases hello
But not with password 'b':
% gpgconf --kill gpg-agent % gpg --decrypt hello.symmetric.asc gpg: AES256 encrypted session key gpg: encrypted with 2 passphrases gpg: decryption failed: Invalid cipher algorithm