Can someone please provide a description of TCB algorithm?
+1
A:
My cryptographic skills are a little bit rusty - but IMHO, Tweaked Codebook = Tweakable Block Cipher.
It's basically ECB with a Tweak, that "patches" ECB's biggests flaws: identical plaintext blocks result in identical ciphertext (exposing your ciphertext to malicious substitution and showing data patterns).
With a plaintext message P, cut in n-bits blocks X1, X2, X3... Xi... Xn
- Xi (XOR) Tweak(i) -> CC
- Encrypt_function(CC) -> Ci
Depending on your implementation, your Tweak is generated using a function of your choice (taking your block number as a parameter). A very simple (unsecure?) one could be:
- Tweak(i) = i
I'm not 100% OK with my answer; at least that's what I remember and that's what I get when looking at an extract of IEEE 1619-2007. I'd really like to read more on this!
Brian Clozel
2010-05-31 12:07:06
I got one doc on implementation from the link you provided to WikiPedia: http://axelkenzo.ru/index.php?downloads=1619-2007-NIST-Submission.pdfIt looks like it has some clues ;)
FractalizeR
2010-05-31 12:24:33
Yep. I didn't put this link in my answer - it seems like there's a copyright issue with this document (see page 1). Keep us updated!
Brian Clozel
2010-05-31 12:50:31