“Rephrase is a specialized passphrase recovery tool for GnuPG […]. If you can nearly remember your GnuPG passphrase - but not quite - then Rephrase may be able to help.

Tell Rephrase the parts of the passphrase you know, and any number of alternatives for the parts you're not sure about; and Rephrase will try all the alternatives, in all possible combinations, and tell you which combination (if any) gives you the correct passphrase.”

Reprase README
P. Lanch