> My question is, for a version 4 sig using DSA and SHA1, do we: > > 2) H(a + b + c) = 160 bit value to be fed into the sig. alg.
It is this one, where the "+" means concatenation. Most implementations of hash functions do not require you to literally concatenate the data, but rather you can pass the data in pieces, so you first pass in a, then b, then c. In the spec we write this as "first hash a, then hash b, then hash c," and so on.
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