another feature RNGs could provide

[Jack Lloyd]

On Mon, Dec 12, 2005 at 12:20:26AM -0600, Travis H. wrote:
> 2) While CTR mode with a random key is sufficient for creating a
> permutation of N-bit blocks for a fixed N, is there a general-purpose
> way to create a N-bit permutation, where N is a variable?  How about
> picking a cryptographically strong permutation on N elements, where N
> is not necessarily a power of 2?

Use can use the Bear or Lion constructions to form 2^{arbitrary} bit block
ciphers quite easily.

-Jack

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