Initial revision

git-svn-id: svn://svn.code.sf.net/p/cryptopp/code/trunk/c5@2 57ff6487-cd31-0410-9ec3-f628ee90f5f0

1 files changed, 58 insertions, 0 deletions

diff --git a/pubkey.cpp b/pubkey.cpp
new file mode 100644
index 0000000..94dc271
--- /dev/null
+++ b/pubkey.cpp
@@ -0,0 +1,58 @@
+// pubkey.cpp - written and placed in the public domain by Wei Dai
+
+#include "pch.h"
+#include "pubkey.h"
+
+NAMESPACE_BEGIN(CryptoPP)
+
+void TF_DigestSignerBase::SignDigest(RandomNumberGenerator &rng, const byte *digest, unsigned int digestLen, byte *signature) const
+{
+	assert(digestLen <= MaxDigestLength());
+
+	SecByteBlock paddedBlock(PaddedBlockByteLength());
+	GetPaddingAlgorithm().Pad(rng, digest, digestLen, paddedBlock, PaddedBlockBitLength());
+	GetTrapdoorFunctionInterface().CalculateRandomizedInverse(rng, Integer(paddedBlock, paddedBlock.size())).Encode(signature, DigestSignatureLength());
+}
+
+bool TF_DigestVerifierBase::VerifyDigest(const byte *digest, unsigned int digestLen, const byte *signature) const
+{
+	SecByteBlock paddedBlock(PaddedBlockByteLength());
+	Integer x = GetTrapdoorFunctionInterface().ApplyFunction(Integer(signature, DigestSignatureLength()));
+	if (x.ByteCount() > paddedBlock.size())
+		x = Integer::Zero();	// don't return false here to prevent timing attack
+	x.Encode(paddedBlock, paddedBlock.size());
+	if (GetPaddingAlgorithm().IsReversible())
+	{
+		SecByteBlock recoveredDigest(MaxDigestLength());
+		DecodingResult result = GetPaddingAlgorithm().Unpad(paddedBlock, PaddedBlockBitLength(), recoveredDigest);
+		return result == DecodingResult(digestLen) && memcmp(digest, recoveredDigest, digestLen) == 0;
+	}
+	else
+	{
+		SecByteBlock paddedBlock2(PaddedBlockByteLength());
+		GetPaddingAlgorithm().Pad(NullRNG(), digest, digestLen, paddedBlock2, PaddedBlockBitLength());
+		return paddedBlock == paddedBlock2;
+	}
+}
+
+DecodingResult TF_DecryptorBase::FixedLengthDecrypt(const byte *cipherText, byte *plainText) const
+{
+	SecByteBlock paddedBlock(PaddedBlockByteLength());
+	Integer x = GetTrapdoorFunctionInterface().CalculateInverse(Integer(cipherText, FixedCiphertextLength()));
+	if (x.ByteCount() > paddedBlock.size())
+		x = Integer::Zero();	// don't return false here to prevent timing attack
+	x.Encode(paddedBlock, paddedBlock.size());
+	return GetPaddingAlgorithm().Unpad(paddedBlock, PaddedBlockBitLength(), plainText);
+}
+
+void TF_EncryptorBase::Encrypt(RandomNumberGenerator &rng, const byte *plainText, unsigned int plainTextLength, byte *cipherText) const
+{
+	if (plainTextLength > FixedMaxPlaintextLength())
+		throw InvalidArgument(AlgorithmName() + ": message too long for this public key");
+
+	SecByteBlock paddedBlock(PaddedBlockByteLength());
+	GetPaddingAlgorithm().Pad(rng, plainText, plainTextLength, paddedBlock, PaddedBlockBitLength());
+	GetTrapdoorFunctionInterface().ApplyRandomizedFunction(rng, Integer(paddedBlock, paddedBlock.size())).Encode(cipherText, FixedCiphertextLength());
+}
+
+NAMESPACE_END