I've been playing with John The Ripper (JtR) to try to crack/audit a salted password that was hashed with SHA-512, with 20 interactions according to the source (for the curious, this is a Rails app, with the authlogic gem).
If I understood things correctly, JtR expects its hashes in a file, where each hash follows certain format. For SHA512, this format appears to be:
which seems to be a format that is compatible with the passwd/shadow files.
My problem is that the hash I have in my DB is a hexdigest while it seems that the hash that JtR expects its in Base64.
Am I right in this ascertion? Is there a way to tell JtR to recognize a hexdigest hash (composed of password + salt) that was 'stretched' 20 times?