SHA-1 --> SHA-512
you need to do:
Start Thunderbird, click Edit -> Preferences. Go to the Config Editor. Locate extensions.enigmail.mimeHashAlgorithm. Set the value to 3, 4 or 5. Default is 0 which means SHA-1. If you set it to 3 Enigmail will use SHA-256, 4 means SHA-384 and 5 SHA-512. If you set the value to 2 Enigmail will use RIPEMD-160. Not a bad choice either.
引用元:
http://jandives.wordpress.com/2011/06/18/sha-256-for-thunderbirds-enigmail/
