diff options
Diffstat (limited to 'gfpcrypt.cpp')
| -rw-r--r-- | gfpcrypt.cpp | 50 |
1 files changed, 34 insertions, 16 deletions
diff --git a/gfpcrypt.cpp b/gfpcrypt.cpp index 8d8b0bf..c27a967 100644 --- a/gfpcrypt.cpp +++ b/gfpcrypt.cpp @@ -63,30 +63,48 @@ bool DL_GroupParameters_DSA::ValidateGroup(RandomNumberGenerator &rng, unsigned return pass; } -Integer NR_EncodeDigest(unsigned int modulusBits, const byte *digest, unsigned int digestLen) +void DL_SignatureMessageEncodingMethod_DSA::ComputeMessageRepresentative(RandomNumberGenerator &rng, + const byte *recoverableMessage, unsigned int recoverableMessageLength, + HashTransformation &hash, HashIdentifier hashIdentifier, bool messageEmpty, + byte *representative, unsigned int representativeBitLength) const { - Integer h; - if (digestLen*8 < modulusBits) - h.Decode(digest, digestLen); - else + assert(recoverableMessageLength == 0); + assert(hashIdentifier.second == 0); + const unsigned int representativeByteLength = BitsToBytes(representativeBitLength); + const unsigned int digestSize = hash.DigestSize(); + const unsigned int paddingLength = SaturatingSubtract(representativeByteLength, digestSize); + + memset(representative, 0, paddingLength); + hash.TruncatedFinal(representative+paddingLength, STDMIN(representativeByteLength, digestSize)); + + if (digestSize*8 > representativeBitLength) { - h.Decode(digest, BitsToBytes(modulusBits)); - h >>= BitsToBytes(modulusBits)*8 - modulusBits + 1; + Integer h(representative, representativeByteLength); + h >>= representativeByteLength*8 - representativeBitLength; + h.Encode(representative, representativeByteLength); } - return h; } -Integer DSA_EncodeDigest(unsigned int modulusBits, const byte *digest, unsigned int digestLen) +void DL_SignatureMessageEncodingMethod_NR::ComputeMessageRepresentative(RandomNumberGenerator &rng, + const byte *recoverableMessage, unsigned int recoverableMessageLength, + HashTransformation &hash, HashIdentifier hashIdentifier, bool messageEmpty, + byte *representative, unsigned int representativeBitLength) const { - Integer h; - if (digestLen*8 <= modulusBits) - h.Decode(digest, digestLen); - else + assert(recoverableMessageLength == 0); + assert(hashIdentifier.second == 0); + const unsigned int representativeByteLength = BitsToBytes(representativeBitLength); + const unsigned int digestSize = hash.DigestSize(); + const unsigned int paddingLength = SaturatingSubtract(representativeByteLength, digestSize); + + memset(representative, 0, paddingLength); + hash.TruncatedFinal(representative+paddingLength, STDMIN(representativeByteLength, digestSize)); + + if (digestSize*8 >= representativeBitLength) { - h.Decode(digest, BitsToBytes(modulusBits)); - h >>= BitsToBytes(modulusBits)*8 - modulusBits; + Integer h(representative, representativeByteLength); + h >>= representativeByteLength*8 - representativeBitLength + 1; + h.Encode(representative, representativeByteLength); } - return h; } bool DL_GroupParameters_IntegerBased::ValidateGroup(RandomNumberGenerator &rng, unsigned int level) const |