Can someone please provide a description of TCB algorithm?
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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!
于 2010-05-31T12:07:06.597 回答