allout-encryption-plaintext-sanitization-regexps is a variable defined in `allout.el'.
Its value is

  • Automatically becomes buffer-local when set.

List of regexps whose matches are removed from plaintext before encryption.

This is for the sake of removing artifacts, like escapes, that are added on
and not actually part of the original plaintext. The removal is done just
prior to encryption.

Entries must be symbols that are bound to the desired values.

Each value can be a regexp or a list with a regexp followed by a
substitution string. If it's just a regexp, all its matches are removed
before the text is encrypted. If it's a regexp and a substitution, the
substitution is used against the regexp matches, a la `replace-match'.