diff options
Diffstat (limited to 'plugins/CryptoPP/crypto/src/pssr.cpp')
| -rw-r--r-- | plugins/CryptoPP/crypto/src/pssr.cpp | 145 |
1 files changed, 145 insertions, 0 deletions
diff --git a/plugins/CryptoPP/crypto/src/pssr.cpp b/plugins/CryptoPP/crypto/src/pssr.cpp new file mode 100644 index 0000000000..34ce71aed6 --- /dev/null +++ b/plugins/CryptoPP/crypto/src/pssr.cpp @@ -0,0 +1,145 @@ +// pssr.cpp - written and placed in the public domain by Wei Dai
+
+#include "pch.h"
+#include "pssr.h"
+#include <functional>
+
+NAMESPACE_BEGIN(CryptoPP)
+
+// more in dll.cpp
+template<> const byte EMSA2HashId<RIPEMD160>::id = 0x31;
+template<> const byte EMSA2HashId<RIPEMD128>::id = 0x32;
+template<> const byte EMSA2HashId<Whirlpool>::id = 0x37;
+
+#ifndef CRYPTOPP_IMPORTS
+
+size_t PSSR_MEM_Base::MinRepresentativeBitLength(size_t hashIdentifierLength, size_t digestLength) const
+{
+ size_t saltLen = SaltLen(digestLength);
+ size_t minPadLen = MinPadLen(digestLength);
+ return 9 + 8*(minPadLen + saltLen + digestLength + hashIdentifierLength);
+}
+
+size_t PSSR_MEM_Base::MaxRecoverableLength(size_t representativeBitLength, size_t hashIdentifierLength, size_t digestLength) const
+{
+ if (AllowRecovery())
+ return SaturatingSubtract(representativeBitLength, MinRepresentativeBitLength(hashIdentifierLength, digestLength)) / 8;
+ return 0;
+}
+
+bool PSSR_MEM_Base::IsProbabilistic() const
+{
+ return SaltLen(1) > 0;
+}
+
+bool PSSR_MEM_Base::AllowNonrecoverablePart() const
+{
+ return true;
+}
+
+bool PSSR_MEM_Base::RecoverablePartFirst() const
+{
+ return false;
+}
+
+void PSSR_MEM_Base::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()));
+
+ const size_t u = hashIdentifier.second + 1;
+ const size_t representativeByteLength = BitsToBytes(representativeBitLength);
+ const size_t digestSize = hash.DigestSize();
+ const size_t saltSize = SaltLen(digestSize);
+ byte *const h = representative + representativeByteLength - u - digestSize;
+
+ SecByteBlock digest(digestSize), salt(saltSize);
+ hash.Final(digest);
+ rng.GenerateBlock(salt, saltSize);
+
+ // compute H = hash of M'
+ byte c[8];
+ PutWord(false, BIG_ENDIAN_ORDER, c, (word32)SafeRightShift<29>(recoverableMessageLength));
+ PutWord(false, BIG_ENDIAN_ORDER, c+4, word32(recoverableMessageLength << 3));
+ hash.Update(c, 8);
+ hash.Update(recoverableMessage, recoverableMessageLength);
+ hash.Update(digest, digestSize);
+ hash.Update(salt, saltSize);
+ hash.Final(h);
+
+ // compute representative
+ GetMGF().GenerateAndMask(hash, representative, representativeByteLength - u - digestSize, h, digestSize, false);
+ byte *xorStart = representative + representativeByteLength - u - digestSize - salt.size() - recoverableMessageLength - 1;
+ xorStart[0] ^= 1;
+ xorbuf(xorStart + 1, recoverableMessage, recoverableMessageLength);
+ xorbuf(xorStart + 1 + recoverableMessageLength, salt, salt.size());
+ memcpy(representative + representativeByteLength - u, hashIdentifier.first, hashIdentifier.second);
+ representative[representativeByteLength - 1] = hashIdentifier.second ? 0xcc : 0xbc;
+ if (representativeBitLength % 8 != 0)
+ representative[0] = (byte)Crop(representative[0], representativeBitLength % 8);
+}
+
+DecodingResult PSSR_MEM_Base::RecoverMessageFromRepresentative(
+ HashTransformation &hash, HashIdentifier hashIdentifier, bool messageEmpty,
+ byte *representative, size_t representativeBitLength,
+ byte *recoverableMessage) const
+{
+ assert(representativeBitLength >= MinRepresentativeBitLength(hashIdentifier.second, hash.DigestSize()));
+
+ const size_t u = hashIdentifier.second + 1;
+ const size_t representativeByteLength = BitsToBytes(representativeBitLength);
+ const size_t digestSize = hash.DigestSize();
+ const size_t saltSize = SaltLen(digestSize);
+ const byte *const h = representative + representativeByteLength - u - digestSize;
+
+ SecByteBlock digest(digestSize);
+ hash.Final(digest);
+
+ DecodingResult result(0);
+ bool &valid = result.isValidCoding;
+ size_t &recoverableMessageLength = result.messageLength;
+
+ valid = (representative[representativeByteLength - 1] == (hashIdentifier.second ? 0xcc : 0xbc)) && valid;
+ valid = (memcmp(representative + representativeByteLength - u, hashIdentifier.first, hashIdentifier.second) == 0) && valid;
+
+ GetMGF().GenerateAndMask(hash, representative, representativeByteLength - u - digestSize, h, digestSize);
+ if (representativeBitLength % 8 != 0)
+ representative[0] = (byte)Crop(representative[0], representativeBitLength % 8);
+
+ // extract salt and recoverableMessage from DB = 00 ... || 01 || M || salt
+ byte *salt = representative + representativeByteLength - u - digestSize - saltSize;
+ byte *M = std::find_if(representative, salt-1, std::bind2nd(std::not_equal_to<byte>(), 0));
+ recoverableMessageLength = salt-M-1;
+ if (*M == 0x01
+ && (size_t)(M - representative - (representativeBitLength % 8 != 0)) >= MinPadLen(digestSize)
+ && recoverableMessageLength <= MaxRecoverableLength(representativeBitLength, hashIdentifier.second, digestSize))
+ {
+ memcpy(recoverableMessage, M+1, recoverableMessageLength);
+ }
+ else
+ {
+ recoverableMessageLength = 0;
+ valid = false;
+ }
+
+ // verify H = hash of M'
+ byte c[8];
+ PutWord(false, BIG_ENDIAN_ORDER, c, (word32)SafeRightShift<29>(recoverableMessageLength));
+ PutWord(false, BIG_ENDIAN_ORDER, c+4, word32(recoverableMessageLength << 3));
+ hash.Update(c, 8);
+ hash.Update(recoverableMessage, recoverableMessageLength);
+ hash.Update(digest, digestSize);
+ hash.Update(salt, saltSize);
+ valid = hash.Verify(h) && valid;
+
+ if (!AllowRecovery() && valid && recoverableMessageLength != 0)
+ {throw NotImplemented("PSSR_MEM: message recovery disabled");}
+
+ return result;
+}
+
+#endif
+
+NAMESPACE_END
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