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/*
* Cipher Modes via CommonCrypto
* (C) 2018 Jose Pereira
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
#include <botan/internal/commoncrypto.h>
#include <botan/internal/commoncrypto_utils.h>
#include <botan/cipher_mode.h>
#include <botan/parsing.h>
#include <botan/internal/rounding.h>
#include <botan/scan_name.h>
namespace Botan {
std::string CommonCrypto_Error::ccryptorstatus_to_string(CCCryptorStatus status)
{
switch(status)
{
case kCCSuccess:
return "Success";
case kCCParamError:
return "ParamError";
case kCCBufferTooSmall:
return "BufferTooSmall";
case kCCMemoryFailure:
return "MemoryFailure";
case kCCAlignmentError:
return "AlignmentError";
case kCCDecodeError:
return "DecodeError";
case kCCUnimplemented:
return "Unimplemented";
case kCCOverflow:
return "Overflow";
case kCCRNGFailure:
return "RNGFailure";
case kCCUnspecifiedError:
return "UnspecifiedError";
case kCCCallSequenceError:
return "CallSequenceError";
case kCCKeySizeError:
return "KeySizeError";
default:
return "Unknown";
}
};
CommonCryptor_Opts commoncrypto_opts_from_algo_name(const std::string& algo_name)
{
CommonCryptor_Opts opts;
if(algo_name.compare(0, 3, "AES") == 0)
{
opts.algo = kCCAlgorithmAES;
opts.block_size = kCCBlockSizeAES128;
if(algo_name == "AES-128")
{
opts.key_spec = Key_Length_Specification(kCCKeySizeAES128);
}
else if(algo_name == "AES-192")
{
opts.key_spec = Key_Length_Specification(kCCKeySizeAES192);
}
else if(algo_name == "AES-256")
{
opts.key_spec = Key_Length_Specification(kCCKeySizeAES256);
}
else
{
throw CommonCrypto_Error("Unknown AES algorithm");
}
}
else if(algo_name == "DES")
{
opts.algo = kCCAlgorithmDES;
opts.block_size = kCCBlockSizeDES;
opts.key_spec = Key_Length_Specification(kCCKeySizeDES);
}
else if(algo_name == "TripleDES")
{
opts.algo = kCCAlgorithm3DES;
opts.block_size = kCCBlockSize3DES;
opts.key_spec = Key_Length_Specification(16, kCCKeySize3DES, 8);
}
else if(algo_name == "Blowfish")
{
opts.algo = kCCAlgorithmBlowfish;
opts.block_size = kCCBlockSizeBlowfish;
opts.key_spec = Key_Length_Specification(1, kCCKeySizeMaxBlowfish, 1);
}
else if(algo_name == "CAST-128")
{
opts.algo = kCCAlgorithmCAST;
opts.block_size = kCCBlockSizeCAST;
// Botan's base implementation of CAST does not support shorter keys
// so we limit its minimum key size to 11 here.
opts.key_spec = Key_Length_Specification(11, kCCKeySizeMaxCAST, 1);
}
else
{
throw CommonCrypto_Error("Unsupported cipher");
}
return opts;
}
CommonCryptor_Opts commoncrypto_opts_from_algo(const std::string& algo)
{
SCAN_Name spec(algo);
std::string algo_name = spec.algo_name();
std::string cipher_mode = spec.cipher_mode();
std::string cipher_mode_padding = spec.cipher_mode_pad();
CommonCryptor_Opts opts = commoncrypto_opts_from_algo_name(algo_name);
//TODO add CFB and XTS support
if(cipher_mode.empty() || cipher_mode == "ECB")
{
opts.mode = kCCModeECB;
}
else if(cipher_mode == "CBC")
{
opts.mode = kCCModeCBC;
}
else if(cipher_mode == "CTR")
{
opts.mode = kCCModeCTR;
}
else if(cipher_mode == "OFB")
{
opts.mode = kCCModeOFB;
}
else
{
throw CommonCrypto_Error("Unsupported cipher mode!");
}
if(cipher_mode_padding == "NoPadding")
{
opts.padding = ccNoPadding;
}
/*
else if(cipher_mode_padding.empty() || cipher_mode_padding == "PKCS7")
{
opts.padding = ccPKCS7Padding;
}
*/
else
{
throw CommonCrypto_Error("Unsupported cipher mode padding!");
}
return opts;
}
void commoncrypto_adjust_key_size(const uint8_t key[], size_t length,
const CommonCryptor_Opts& opts, secure_vector<uint8_t>& full_key)
{
if(opts.algo == kCCAlgorithmBlowfish && length < 8)
{
size_t repeat;
switch(length)
{
case 1:
repeat = 8;
break;
case 2:
repeat = 4;
break;
case 3:
repeat = 3;
break;
default:
repeat = 2;
break;
}
full_key.resize(length * repeat);
for(size_t i = 0; i < repeat; i++)
{
copy_mem(full_key.data() + i * length, key, length);
}
}
else if(opts.algo == kCCAlgorithm3DES && length == 16)
{
full_key += std::make_pair(key, 8);
}
}
}