Re: Block Cipher Applications

David Wagner <daw@xxxxxxxxxxxxxxxxxxxxxxxx> wrote:
That line of thinking doesn't sound wise to me. You'd have to be very
careful about how you set up such a combination, or else it could easily
end up with subtle security flaws. Personally, I wouldn't recommend
re-using a single key for both purposes like this, as it's too easy to
screw something up.

Agreed - not to mention it's so easy to:
enckey = HMAC(key, 0);
intkey = HMAC(key, 1);

JLC

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