I have a question regarding the resulting sizes of the blocks and shift registers in Cipher Feedback Mode.
In the web there are different pictures to illustrate the CFB-mode.
Now on the first picture there are no shift registers at all. I dont understand which special case the first picture describes. Is really the entire ciphertext (after the XOR with the plaintext) is taken as the argument in for the next block or just s bits?
What if I use the CFB-128 Mode with the following assumptions:
- IV size is 128bits
- Key is 128bits
- CFB-Mode is CFB128
- Plaintext is 256bits.
Is the resulting ciphertext of this operation always the size of the Key (128 bits in this case)? If yes is the ENTIRE ciphertext taken as the argument for the next Encryption block? I am confused about the sizes and the pictures describing it.
EDIT: Another question which I have is: What is the resulting ciphertext at the end? Is it just the last ciphertext block or is it a concatenation of all blocks (c0+c1+c2...+cn)?