Please refer `Mew with GnuPG on Cygwin' page for the usage of the following file.
The file above is a derivation from `gnupg-1.0.4d-mew.lzh' patch, which is provided in Mew $B$H(B GnuPG $B$H(B Emacs page by <firstname.lastname@example.org> (whose real name is unknown).
WATANABE Katsuhiro worked on modifying `gnupg-1.0.4d-mew.lzh' in order to apply it to GnuPG 1.0.7, and made the patch `gnupg-passphrase-cygwin.patch'.
Although there is no clear statement about the licence terms of `gnupg-1.0.4d-mew.lzh', it may be distributed under the terms of GPL, following the licence terms of GnuPG. Considering these conditions, it is a natural consequence that the patch `gnupg-passphrase-cygwin.patch' may be distributed under the terms of GPL, also.