513 lines
16 KiB
C++
513 lines
16 KiB
C++
// xts.cpp - written and placed in the public domain by Jeffrey Walton
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// Aarch32, Aarch64, Altivec and X86_64 include SIMD as part of the
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// base architecture. We can use the SIMD code below without an
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// architecture option. No runtime tests are required. Unfortunately,
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// we can't use it on Altivec because an architecture switch is required.
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// The updated XorBuffer gains 0.3 to 1.5 cpb on the architectures for
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// 16-byte block sizes.
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#include "pch.h"
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#include "xts.h"
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#include "misc.h"
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#include "modes.h"
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#include "cpu.h"
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#if defined(CRYPTOPP_DEBUG)
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# include "aes.h"
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# include "threefish.h"
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#endif
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// 0.3 to 0.4 cpb profit
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#if defined(__SSE2__) || defined(_M_X64)
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# include <emmintrin.h>
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#endif
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#if defined(__aarch32__) || defined(__aarch64__) || defined(_M_ARM64)
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# if (CRYPTOPP_ARM_NEON_HEADER)
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# include <arm_neon.h>
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# endif
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#endif
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#if defined(__ALTIVEC__)
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# include "ppc_simd.h"
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#endif
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ANONYMOUS_NAMESPACE_BEGIN
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using namespace CryptoPP;
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#if defined(CRYPTOPP_DEBUG) && !defined(CRYPTOPP_DOXYGEN_PROCESSING)
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using CryptoPP::AES;
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using CryptoPP::XTS_Mode;
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using CryptoPP::Threefish512;
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void Modes_TestInstantiations()
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{
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XTS_Mode<AES>::Encryption m0;
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XTS_Mode<AES>::Decryption m1;
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XTS_Mode<AES>::Encryption m2;
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XTS_Mode<AES>::Decryption m3;
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#if CRYPTOPP_XTS_WIDE_BLOCK_CIPHERS
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XTS_Mode<Threefish512>::Encryption m4;
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XTS_Mode<Threefish512>::Decryption m5;
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#endif
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}
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#endif // CRYPTOPP_DEBUG
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inline void XorBuffer(byte *output, const byte *input, const byte *mask, size_t count)
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{
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CRYPTOPP_ASSERT(count >= 16 && (count % 16 == 0));
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#if defined(CRYPTOPP_DISABLE_ASM)
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xorbuf(output, input, mask, count);
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#elif defined(__SSE2__) || defined(_M_X64)
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for (size_t i=0; i<count; i+=16)
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_mm_storeu_si128(M128_CAST(output+i),
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_mm_xor_si128(
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_mm_loadu_si128(CONST_M128_CAST(input+i)),
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_mm_loadu_si128(CONST_M128_CAST(mask+i))));
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#elif defined(__aarch32__) || defined(__aarch64__) || defined(_M_ARM64)
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for (size_t i=0; i<count; i+=16)
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vst1q_u8(output+i, veorq_u8(vld1q_u8(input+i), vld1q_u8(mask+i)));
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#elif defined(__ALTIVEC__)
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for (size_t i=0; i<count; i+=16)
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VecStore(VecXor(VecLoad(input+i), VecLoad(mask+i)), output+i);
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#else
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xorbuf(output, input, mask, count);
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#endif
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}
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inline void XorBuffer(byte *buf, const byte *mask, size_t count)
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{
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XorBuffer(buf, buf, mask, count);
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}
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// Borrowed from CMAC, but little-endian representation
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inline void GF_Double(byte *out, const byte* in, unsigned int len)
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{
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#if defined(_M_X64) || defined(_M_ARM64) || defined(_LP64) || defined(__LP64__)
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word64 carry = 0, x;
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for (size_t i=0, idx=0; i<len/8; ++i, idx+=8)
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{
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x = GetWord<word64>(false, LITTLE_ENDIAN_ORDER, in+idx);
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word64 y = (x >> 63); x = (x << 1) + carry;
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PutWord<word64>(false, LITTLE_ENDIAN_ORDER, out+idx, x);
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carry = y;
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}
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#else
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word32 carry = 0, x;
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for (size_t i=0, idx=0; i<len/4; ++i, idx+=4)
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{
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x = GetWord<word32>(false, LITTLE_ENDIAN_ORDER, in+idx);
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word32 y = (x >> 31); x = (x << 1) + carry;
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PutWord<word32>(false, LITTLE_ENDIAN_ORDER, out+idx, x);
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carry = y;
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}
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#endif
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#if CRYPTOPP_XTS_WIDE_BLOCK_CIPHERS
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CRYPTOPP_ASSERT(IsPowerOf2(len));
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CRYPTOPP_ASSERT(len >= 16);
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CRYPTOPP_ASSERT(len <= 128);
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byte* k = out;
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if (carry)
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{
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switch (len)
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{
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case 16:
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{
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const size_t LEIDX = 16-1;
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k[LEIDX-15] ^= 0x87;
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break;
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}
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case 32:
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{
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// https://crypto.stackexchange.com/q/9815/10496
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// Polynomial x^256 + x^10 + x^5 + x^2 + 1
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const size_t LEIDX = 32-1;
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k[LEIDX-30] ^= 4;
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k[LEIDX-31] ^= 0x25;
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break;
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}
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case 64:
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{
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// https://crypto.stackexchange.com/q/9815/10496
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// Polynomial x^512 + x^8 + x^5 + x^2 + 1
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const size_t LEIDX = 64-1;
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k[LEIDX-62] ^= 1;
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k[LEIDX-63] ^= 0x25;
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break;
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}
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case 128:
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{
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// https://crypto.stackexchange.com/q/9815/10496
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// Polynomial x^1024 + x^19 + x^6 + x + 1
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const size_t LEIDX = 128-1;
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k[LEIDX-125] ^= 8;
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k[LEIDX-126] ^= 0x00;
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k[LEIDX-127] ^= 0x43;
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break;
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}
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default:
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CRYPTOPP_ASSERT(0);
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}
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}
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#else
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CRYPTOPP_ASSERT(len == 16);
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byte* k = out;
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if (carry)
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{
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k[0] ^= 0x87;
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return;
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}
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#endif // CRYPTOPP_XTS_WIDE_BLOCK_CIPHERS
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}
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inline void GF_Double(byte *inout, unsigned int len)
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{
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GF_Double(inout, inout, len);
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}
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ANONYMOUS_NAMESPACE_END
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NAMESPACE_BEGIN(CryptoPP)
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void XTS_ModeBase::ThrowIfInvalidBlockSize(size_t length)
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{
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#if CRYPTOPP_XTS_WIDE_BLOCK_CIPHERS
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CRYPTOPP_ASSERT(length >= 16 && length <= 128 && IsPowerOf2(length));
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if (length < 16 || length > 128 || !IsPowerOf2(length))
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throw InvalidArgument(AlgorithmName() + ": block size of underlying block cipher is not valid");
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#else
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CRYPTOPP_ASSERT(length == 16);
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if (length != 16)
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throw InvalidArgument(AlgorithmName() + ": block size of underlying block cipher is not 16");
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#endif
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}
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void XTS_ModeBase::ThrowIfInvalidKeyLength(size_t length)
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{
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CRYPTOPP_ASSERT(length % 2 == 0);
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if (!GetBlockCipher().IsValidKeyLength((length+1)/2))
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throw InvalidKeyLength(AlgorithmName(), length);
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}
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void XTS_ModeBase::SetKey(const byte *key, size_t length, const NameValuePairs ¶ms)
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{
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ThrowIfInvalidKeyLength(length);
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ThrowIfInvalidBlockSize(BlockSize());
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const size_t klen = length/2;
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AccessBlockCipher().SetKey(key+0, klen, params);
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AccessTweakCipher().SetKey(key+klen, klen, params);
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ResizeBuffers();
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size_t ivLength;
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const byte *iv = GetIVAndThrowIfInvalid(params, ivLength);
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Resynchronize(iv, (int)ivLength);
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}
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void XTS_ModeBase::Resynchronize(const byte *iv, int ivLength)
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{
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BlockOrientedCipherModeBase::Resynchronize(iv, ivLength);
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std::memcpy(m_xregister, m_register, ivLength);
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GetTweakCipher().ProcessBlock(m_xregister);
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}
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void XTS_ModeBase::Resynchronize(word64 sector, ByteOrder order)
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{
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SecByteBlock iv(GetTweakCipher().BlockSize());
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PutWord<word64>(false, order, iv, sector);
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std::memset(iv+8, 0x00, iv.size()-8);
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BlockOrientedCipherModeBase::Resynchronize(iv, (int)iv.size());
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std::memcpy(m_xregister, iv, iv.size());
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GetTweakCipher().ProcessBlock(m_xregister);
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}
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void XTS_ModeBase::ResizeBuffers()
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{
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BlockOrientedCipherModeBase::ResizeBuffers();
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m_xworkspace.New(GetBlockCipher().BlockSize()*ParallelBlocks);
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m_xregister.New(GetBlockCipher().BlockSize()*ParallelBlocks);
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}
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// ProcessData runs either 12-4-1 blocks, 8-2-1 or 4-1 blocks. Which is
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// selected depends on ParallelBlocks in the header file. 12-4-1 or 8-2-1
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// can be used on Aarch64 and PowerPC. Intel should use 4-1 due to lack
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// of registers. The unneeded code paths should be removed by optimizer.
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// The extra gyrations save us 1.8 cpb on Aarch64 and 2.1 cpb on PowerPC.
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void XTS_ModeBase::ProcessData(byte *outString, const byte *inString, size_t length)
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{
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// data unit is multiple of 16 bytes
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CRYPTOPP_ASSERT(length % BlockSize() == 0);
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enum { lastParallelBlock = ParallelBlocks-1 };
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const unsigned int blockSize = GetBlockCipher().BlockSize();
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const size_t parallelSize = blockSize*ParallelBlocks;
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// encrypt the data unit, optimal size at a time
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while (length >= parallelSize)
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{
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// m_xregister[0] always points to the next tweak.
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GF_Double(m_xregister+1*blockSize, m_xregister+0*blockSize, blockSize);
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GF_Double(m_xregister+2*blockSize, m_xregister+1*blockSize, blockSize);
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GF_Double(m_xregister+3*blockSize, m_xregister+2*blockSize, blockSize);
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if (ParallelBlocks > 4)
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{
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GF_Double(m_xregister+4*blockSize, m_xregister+3*blockSize, blockSize);
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GF_Double(m_xregister+5*blockSize, m_xregister+4*blockSize, blockSize);
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GF_Double(m_xregister+6*blockSize, m_xregister+5*blockSize, blockSize);
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GF_Double(m_xregister+7*blockSize, m_xregister+6*blockSize, blockSize);
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}
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if (ParallelBlocks > 8)
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{
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GF_Double(m_xregister+8*blockSize, m_xregister+7*blockSize, blockSize);
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GF_Double(m_xregister+9*blockSize, m_xregister+8*blockSize, blockSize);
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GF_Double(m_xregister+10*blockSize, m_xregister+9*blockSize, blockSize);
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GF_Double(m_xregister+11*blockSize, m_xregister+10*blockSize, blockSize);
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}
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// merge the tweak into the input block
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XorBuffer(m_xworkspace, inString, m_xregister, parallelSize);
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// encrypt one block, merge the tweak into the output block
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GetBlockCipher().AdvancedProcessBlocks(m_xworkspace, m_xregister,
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outString, parallelSize, BlockTransformation::BT_AllowParallel);
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// m_xregister[0] always points to the next tweak.
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GF_Double(m_xregister+0, m_xregister+lastParallelBlock*blockSize, blockSize);
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inString += parallelSize;
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outString += parallelSize;
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length -= parallelSize;
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}
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// encrypt the data unit, 4 blocks at a time
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while (ParallelBlocks == 12 && length >= blockSize*4)
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{
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// m_xregister[0] always points to the next tweak.
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GF_Double(m_xregister+1*blockSize, m_xregister+0*blockSize, blockSize);
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GF_Double(m_xregister+2*blockSize, m_xregister+1*blockSize, blockSize);
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GF_Double(m_xregister+3*blockSize, m_xregister+2*blockSize, blockSize);
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// merge the tweak into the input block
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XorBuffer(m_xworkspace, inString, m_xregister, blockSize*4);
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// encrypt one block, merge the tweak into the output block
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GetBlockCipher().AdvancedProcessBlocks(m_xworkspace, m_xregister,
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outString, blockSize*4, BlockTransformation::BT_AllowParallel);
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// m_xregister[0] always points to the next tweak.
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GF_Double(m_xregister+0, m_xregister+3*blockSize, blockSize);
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inString += blockSize*4;
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outString += blockSize*4;
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length -= blockSize*4;
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}
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// encrypt the data unit, 2 blocks at a time
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while (ParallelBlocks == 8 && length >= blockSize*2)
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{
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// m_xregister[0] always points to the next tweak.
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GF_Double(m_xregister+1*blockSize, m_xregister+0*blockSize, blockSize);
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// merge the tweak into the input block
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XorBuffer(m_xworkspace, inString, m_xregister, blockSize*2);
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// encrypt one block, merge the tweak into the output block
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GetBlockCipher().AdvancedProcessBlocks(m_xworkspace, m_xregister,
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outString, blockSize*2, BlockTransformation::BT_AllowParallel);
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// m_xregister[0] always points to the next tweak.
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GF_Double(m_xregister+0, m_xregister+1*blockSize, blockSize);
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inString += blockSize*2;
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outString += blockSize*2;
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length -= blockSize*2;
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}
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// encrypt the data unit, blocksize at a time
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while (length)
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{
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// merge the tweak into the input block
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XorBuffer(m_xworkspace, inString, m_xregister, blockSize);
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// encrypt one block
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GetBlockCipher().ProcessBlock(m_xworkspace);
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// merge the tweak into the output block
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XorBuffer(outString, m_xworkspace, m_xregister, blockSize);
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// Multiply T by alpha
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GF_Double(m_xregister, blockSize);
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inString += blockSize;
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outString += blockSize;
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length -= blockSize;
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}
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}
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size_t XTS_ModeBase::ProcessLastBlock(byte *outString, size_t outLength, const byte *inString, size_t inLength)
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{
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// need at least a full AES block
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CRYPTOPP_ASSERT(inLength >= BlockSize());
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if (inLength < BlockSize())
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throw InvalidArgument("XTS: message is too short for ciphertext stealing");
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if (IsForwardTransformation())
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return ProcessLastPlainBlock(outString, outLength, inString, inLength);
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else
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return ProcessLastCipherBlock(outString, outLength, inString, inLength);
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}
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size_t XTS_ModeBase::ProcessLastPlainBlock(byte *outString, size_t outLength, const byte *inString, size_t inLength)
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{
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// ensure output buffer is large enough
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CRYPTOPP_ASSERT(outLength >= inLength);
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const unsigned int blockSize = GetBlockCipher().BlockSize();
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const size_t blocks = inLength / blockSize;
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const size_t tail = inLength % blockSize;
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outLength = inLength;
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if (tail == 0)
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{
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// Allow ProcessData to handle all the full blocks
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ProcessData(outString, inString, inLength);
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return inLength;
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}
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else if (blocks > 1)
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{
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// Allow ProcessData to handle full blocks except one
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const size_t head = (blocks-1)*blockSize;
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ProcessData(outString, inString, inLength-head);
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outString += head;
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inString += head; inLength -= head;
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}
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///// handle the full block /////
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// merge the tweak into the input block
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XorBuffer(m_xworkspace, inString, m_xregister, blockSize);
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// encrypt one block
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GetBlockCipher().ProcessBlock(m_xworkspace);
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// merge the tweak into the output block
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XorBuffer(outString, m_xworkspace, m_xregister, blockSize);
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// Multiply T by alpha
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GF_Double(m_xregister, blockSize);
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///// handle final partial block /////
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inString += blockSize;
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outString += blockSize;
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const size_t len = inLength-blockSize;
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// copy in the final plaintext bytes
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std::memcpy(m_xworkspace, inString, len);
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// and copy out the final ciphertext bytes
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std::memcpy(outString, outString-blockSize, len);
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// "steal" ciphertext to complete the block
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std::memcpy(m_xworkspace+len, outString-blockSize+len, blockSize-len);
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// merge the tweak into the input block
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XorBuffer(m_xworkspace, m_xregister, blockSize);
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// encrypt one block
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GetBlockCipher().ProcessBlock(m_xworkspace);
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// merge the tweak into the previous output block
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XorBuffer(outString-blockSize, m_xworkspace, m_xregister, blockSize);
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return outLength;
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}
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size_t XTS_ModeBase::ProcessLastCipherBlock(byte *outString, size_t outLength, const byte *inString, size_t inLength)
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{
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// ensure output buffer is large enough
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CRYPTOPP_ASSERT(outLength >= inLength);
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const unsigned int blockSize = GetBlockCipher().BlockSize();
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const size_t blocks = inLength / blockSize;
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const size_t tail = inLength % blockSize;
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outLength = inLength;
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if (tail == 0)
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{
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// Allow ProcessData to handle all the full blocks
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ProcessData(outString, inString, inLength);
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return inLength;
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}
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else if (blocks > 1)
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{
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// Allow ProcessData to handle full blocks except one
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const size_t head = (blocks-1)*blockSize;
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ProcessData(outString, inString, inLength-head);
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outString += head;
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inString += head; inLength -= head;
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}
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#define poly1 (m_xregister+0*blockSize)
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#define poly2 (m_xregister+1*blockSize)
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GF_Double(poly2, poly1, blockSize);
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///// handle final partial block /////
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inString += blockSize;
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outString += blockSize;
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const size_t len = inLength-blockSize;
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// merge the tweak into the input block
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XorBuffer(m_xworkspace, inString-blockSize, poly2, blockSize);
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// encrypt one block
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GetBlockCipher().ProcessBlock(m_xworkspace);
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// merge the tweak into the output block
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XorBuffer(m_xworkspace, poly2, blockSize);
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// copy in the final plaintext bytes
|
|
std::memcpy(outString-blockSize, inString, len);
|
|
// and copy out the final ciphertext bytes
|
|
std::memcpy(outString, m_xworkspace, len);
|
|
// "steal" ciphertext to complete the block
|
|
std::memcpy(outString-blockSize+len, m_xworkspace+len, blockSize-len);
|
|
|
|
///// handle the full previous block /////
|
|
|
|
inString -= blockSize;
|
|
outString -= blockSize;
|
|
|
|
// merge the tweak into the input block
|
|
XorBuffer(m_xworkspace, outString, poly1, blockSize);
|
|
|
|
// encrypt one block
|
|
GetBlockCipher().ProcessBlock(m_xworkspace);
|
|
|
|
// merge the tweak into the output block
|
|
XorBuffer(outString, m_xworkspace, poly1, blockSize);
|
|
|
|
return outLength;
|
|
}
|
|
|
|
NAMESPACE_END
|