allout-passphrase-verifier-string is a variable defined in `allout.el'.
Its value is

  • Automatically becomes buffer-local when set.
  • This variable is obsolete since 23.3;
    use `allout-passphrase-verifier-string' instead.
  • This variable is safe as a file local variable if its value
    satisfies the predicate `stringp'.

Setting used to test solicited encryption passphrases against the one
already associated with a file.

It consists of an encrypted random string useful only to verify that a
passphrase entered by the user is effective for decryption. The passphrase
itself is *not* recorded in the file anywhere, and the encrypted contents
are random binary characters to avoid exposing greater susceptibility to
search attacks.

The verifier string is retained as an Emacs file variable, as well as in
the Emacs buffer state, if file variable adjustments are enabled. See
`allout-enable-file-variable-adjustment' for details about that.