crypto.stackex has an interesting discussion on EtM and MtE: http://crypto.stackexchange.com/questions/202/should-we-mac-... One interesting take away was, Bruce Schneier is of opinion that MtE (Cryptographic Doom acc to Moxie) is more practical than EtM.

Interesting to note that different security protocols on the Internet prefer different schemes:

    1. SSH does Encrypt and MAC
    2. SSL uses MtE
    3. IPSec prefers EtM

Also see: Authenticating users over REST http://restcookbook.com/Basics/loggingin/ which glances at the details not covered by the blog post (using nonce to prevent replay attacks, for instance).