utility for cryptographic attestation of patches sent via email

 This utility allows an easy way to add end-to-end cryptographic
 attestation to patches sent via mail. It does so by adapting the DKIM
 email signature standard to include cryptographic signatures via the
 X-Developer-Signature email header.
 .
 If your project workflow doesn't use patches sent via email, then you
 don't need this and should simply start signing your tags and commits.