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check ciphertext length in TF_DecryptorBase::Decrypt()

pull/2/head
weidai 2010-06-18 01:18:22 +00:00
parent 0980f65266
commit 8af9520702
1 changed files with 4 additions and 1 deletions
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5
pubkey.cpp
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@ -134,8 +134,11 @@ DecodingResult TF_VerifierBase::RecoverAndRestart(byte *recoveredMessage, PK_Mes
DecodingResult TF_DecryptorBase::Decrypt(RandomNumberGenerator &rng, const byte *ciphertext, size_t ciphertextLength, byte *plaintext, const NameValuePairs &parameters) const DecodingResult TF_DecryptorBase::Decrypt(RandomNumberGenerator &rng, const byte *ciphertext, size_t ciphertextLength, byte *plaintext, const NameValuePairs &parameters) const
{ {
if (ciphertextLength != FixedCiphertextLength())
throw InvalidArgument(AlgorithmName() + ": ciphertext length of " + IntToString(ciphertextLength) + " doesn't match the required length of " + IntToString(FixedCiphertextLength()) + " for this key");
SecByteBlock paddedBlock(PaddedBlockByteLength()); SecByteBlock paddedBlock(PaddedBlockByteLength());
Integer x = GetTrapdoorFunctionInterface().CalculateInverse(rng, Integer(ciphertext, FixedCiphertextLength())); Integer x = GetTrapdoorFunctionInterface().CalculateInverse(rng, Integer(ciphertext, ciphertextLength));
if (x.ByteCount() > paddedBlock.size()) if (x.ByteCount() > paddedBlock.size())
x = Integer::Zero(); // don't return false here to prevent timing attack x = Integer::Zero(); // don't return false here to prevent timing attack
x.Encode(paddedBlock, paddedBlock.size()); x.Encode(paddedBlock, paddedBlock.size());