Plaintext inference


Wow! This is an interesting comment (see below). Until now, I was unaware that
there were ways to infer the length of plaintext from the length of ciphertext.
It is my understanding that the initialization and/or synchronization vector
used in encryption would mitigate the potential for plaintext length inference.
Can you
give me some examples of algorithms that do this because this has me really

"Most encryption algorithms roughly preserve the length of the plaintext.
They may pad it up to be a multiple of the the block size, usually 8 or
16 bytes.  Therefore the length of the plaintext can be inferred from
the length of the ciphertext, to within 8-16 bytes."



Aaron J. Ferguson, Ph.D.
PricewaterhouseCoopers LLP
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Received on Monday, 13 November 2000 08:25:52 UTC