From 490d36e65ac24e34e3021c2a0947384aee138c88 Mon Sep 17 00:00:00 2001 From: Malf Furious Date: Wed, 13 Apr 2016 21:05:14 -0400 Subject: Root commit for new Compass repository This is the Alpha version of ComPASS, originally developed sometime in 2014. --- cryptopp562/emsa2.cpp | 34 ++++++++++++++++++++++++++++++++++ 1 file changed, 34 insertions(+) create mode 100644 cryptopp562/emsa2.cpp (limited to 'cryptopp562/emsa2.cpp') diff --git a/cryptopp562/emsa2.cpp b/cryptopp562/emsa2.cpp new file mode 100644 index 0000000..3dbb7e8 --- /dev/null +++ b/cryptopp562/emsa2.cpp @@ -0,0 +1,34 @@ +// emsa2.cpp - written and placed in the public domain by Wei Dai + +#include "pch.h" +#include "emsa2.h" + +#ifndef CRYPTOPP_IMPORTS + +NAMESPACE_BEGIN(CryptoPP) + +void EMSA2Pad::ComputeMessageRepresentative(RandomNumberGenerator &rng, + const byte *recoverableMessage, size_t recoverableMessageLength, + HashTransformation &hash, HashIdentifier hashIdentifier, bool messageEmpty, + byte *representative, size_t representativeBitLength) const +{ + assert(representativeBitLength >= MinRepresentativeBitLength(hashIdentifier.second, hash.DigestSize())); + + if (representativeBitLength % 8 != 7) + throw PK_SignatureScheme::InvalidKeyLength("EMSA2: EMSA2 requires a key length that is a multiple of 8"); + + size_t digestSize = hash.DigestSize(); + size_t representativeByteLength = BitsToBytes(representativeBitLength); + + representative[0] = messageEmpty ? 0x4b : 0x6b; + memset(representative+1, 0xbb, representativeByteLength-digestSize-4); // pad with 0xbb + byte *afterP2 = representative+representativeByteLength-digestSize-3; + afterP2[0] = 0xba; + hash.Final(afterP2+1); + representative[representativeByteLength-2] = *hashIdentifier.first; + representative[representativeByteLength-1] = 0xcc; +} + +NAMESPACE_END + +#endif -- cgit v1.2.3