The OCB mode of authenticated encryption (used for example with AES) is the fastest way to provide authenticity and confidentiality without having to strive into questions like: Encrypt then MAC, MAC ...
I've just come across this piece of code in Bouncy Castle's implementation of OCB Mode: ...
At the beginning of OCB's white paper [pdf], OCB is compared to other modes, and non-malleability is one of the properties advertised. At the end of the paper, it is mentioned the MAC length can be ...
Assuming the following: Key is randomly generated is being used (32 bytes+) IV is also randomly generated Crypto random key generator is used Data being encrypted contains common bytes like ...