// Decryption functions
bool BotanRSA::decrypt(PrivateKey* privateKey, const ByteString& encryptedData,
ByteString& data, const AsymMech::Type padding)
{
// Check if the private key is the right type
if (!privateKey->isOfType(BotanRSAPrivateKey::type))
{
ERROR_MSG("Invalid key type supplied");
return false;
}
std::string eme;
switch (padding)
{
case AsymMech::RSA_PKCS:
eme = "PKCS1v15";
break;
case AsymMech::RSA_PKCS_OAEP:
eme = "EME1(SHA-160)";
break;
case AsymMech::RSA:
eme = "Raw";
break;
default:
ERROR_MSG("Invalid padding mechanism supplied (%i)", padding);
return false;
}
BotanRSAPrivateKey* pk = (BotanRSAPrivateKey*) privateKey;
Botan::RSA_PrivateKey* botanKey = pk->getBotanKey();
if (!botanKey)
{
ERROR_MSG("Could not get the Botan private key");
return false;
}
Botan::PK_Decryptor_EME* decryptor = NULL;
try
{
decryptor = new Botan::PK_Decryptor_EME(*botanKey, eme);
}
catch (...)
{
ERROR_MSG("Could not create the decryptor token");
return false;
}
// Perform the decryption operation
#if BOTAN_VERSION_MINOR == 11
Botan::secure_vector<Botan::byte> decResult;
#else
Botan::SecureVector<Botan::byte> decResult;
#endif
try
{
decResult = decryptor->decrypt(encryptedData.const_byte_str(), encryptedData.size());
}
catch (...)
{
ERROR_MSG("Could not decrypt the data");
delete decryptor;
return false;
}
// Return the result
if (padding == AsymMech::RSA)
{
// We compensate that Botan removes leading zeros
int modSize = pk->getN().size();
int decSize = decResult.size();
data.resize(modSize);
#if BOTAN_VERSION_MINOR == 11
memcpy(&data[0] + modSize - decSize, decResult.data(), decSize);
#else
memcpy(&data[0] + modSize - decSize, decResult.begin(), decSize);
#endif
}
else
{
data.resize(decResult.size());
#if BOTAN_VERSION_MINOR == 11
memcpy(&data[0], decResult.data(), decResult.size());
#else
memcpy(&data[0], decResult.begin(), decResult.size());
#endif
}
delete decryptor;
return true;
}
// Decryption functions
bool BotanRSA::decrypt(PrivateKey* privateKey, const ByteString& encryptedData, ByteString& data, const std::string padding)
{
// Check if the private key is the right type
if (!privateKey->isOfType(BotanRSAPrivateKey::type))
{
ERROR_MSG("Invalid key type supplied");
return false;
}
std::string lowerPadding;
lowerPadding.resize(padding.size());
std::transform(padding.begin(), padding.end(), lowerPadding.begin(), tolower);
std::string eme;
if (!lowerPadding.compare("rsa-pkcs"))
{
eme = "PKCS1v15";
}
else if (!lowerPadding.compare("rsa-pkcs-oaep"))
{
eme = "EME1(SHA-160)";
}
else if (!lowerPadding.compare("rsa-raw"))
{
eme = "Raw";
}
else
{
ERROR_MSG("Invalid padding mechanism supplied (%s)", padding.c_str());
return false;
}
BotanRSAPrivateKey* pk = (BotanRSAPrivateKey*) privateKey;
Botan::RSA_PrivateKey* botanKey = pk->getBotanKey();
if (!botanKey)
{
ERROR_MSG("Could not get the Botan private key");
return false;
}
Botan::PK_Decryptor_EME* decryptor = NULL;
try
{
decryptor = new Botan::PK_Decryptor_EME(*botanKey, eme);
}
catch (...)
{
ERROR_MSG("Could not create the decryptor token");
return false;
}
// Perform the decryption operation
Botan::SecureVector<Botan::byte> decResult;
try
{
decResult = decryptor->decrypt(encryptedData.const_byte_str(), encryptedData.size());
}
catch (...)
{
ERROR_MSG("Could not decrypt the data");
delete decryptor;
return false;
}
// Return the result
if (!eme.compare("Raw"))
{
// We compensate that Botan removes leading zeros
int modSize = pk->getN().size();
int decSize = decResult.size();
data.resize(modSize);
memcpy(&data[0] + modSize - decSize, decResult.begin(), decSize);
}
else
{
data.resize(decResult.size());
memcpy(&data[0], decResult.begin(), decResult.size());
}
delete decryptor;
return true;
}
