153 lines
5.4 KiB
C++
153 lines
5.4 KiB
C++
// chacha.cpp - written and placed in the public domain by Jeffrey Walton.
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// Based on Wei Dai's Salsa20 and Bernstein's reference ChaCha
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// family implementation at http://cr.yp.to/chacha.html.
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#include "pch.h"
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#include "config.h"
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#include "chacha.h"
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#include "argnames.h"
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#include "misc.h"
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#include "cpu.h"
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NAMESPACE_BEGIN(CryptoPP)
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#define CHACHA_QUARTER_ROUND(a,b,c,d) \
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a += b; d ^= a; d = rotlConstant<16,word32>(d); \
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c += d; b ^= c; b = rotlConstant<12,word32>(b); \
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a += b; d ^= a; d = rotlConstant<8,word32>(d); \
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c += d; b ^= c; b = rotlConstant<7,word32>(b);
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#if defined(CRYPTOPP_DEBUG) && !defined(CRYPTOPP_DOXYGEN_PROCESSING)
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void ChaCha_TestInstantiations()
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{
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ChaCha8::Encryption x1;
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ChaCha12::Encryption x2;
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ChaCha20::Encryption x3;
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}
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#endif
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template <unsigned int R>
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void ChaCha_Policy<R>::CipherSetKey(const NameValuePairs ¶ms, const byte *key, size_t length)
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{
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CRYPTOPP_UNUSED(params);
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CRYPTOPP_ASSERT(length == 16 || length == 32);
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// "expand 16-byte k" or "expand 32-byte k"
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m_state[0] = 0x61707865;
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m_state[1] = (length == 16) ? 0x3120646e : 0x3320646e;
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m_state[2] = (length == 16) ? 0x79622d36 : 0x79622d32;
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m_state[3] = 0x6b206574;
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GetBlock<word32, LittleEndian> get1(key);
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get1(m_state[4])(m_state[5])(m_state[6])(m_state[7]);
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GetBlock<word32, LittleEndian> get2(key + ((length == 32) ? 16 : 0));
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get2(m_state[8])(m_state[9])(m_state[10])(m_state[11]);
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}
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template <unsigned int R>
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void ChaCha_Policy<R>::CipherResynchronize(byte *keystreamBuffer, const byte *IV, size_t length)
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{
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CRYPTOPP_UNUSED(keystreamBuffer), CRYPTOPP_UNUSED(length);
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CRYPTOPP_ASSERT(length==8);
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GetBlock<word32, LittleEndian> get(IV);
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m_state[12] = m_state[13] = 0;
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get(m_state[14])(m_state[15]);
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}
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template<unsigned int R>
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void ChaCha_Policy<R>::SeekToIteration(lword iterationCount)
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{
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CRYPTOPP_UNUSED(iterationCount);
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throw NotImplemented(std::string(ChaCha_Info<R>::StaticAlgorithmName()) + ": SeekToIteration is not yet implemented");
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// TODO: these were Salsa20, and Wei re-arranged the state array for SSE2 operations.
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// If we can generate some out-of-band test vectors, then test and implement. Also
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// see the test vectors in salsa.txt and the use of Seek test argument.
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// m_state[8] = (word32)iterationCount;
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// m_state[5] = (word32)SafeRightShift<32>(iterationCount);
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}
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template<unsigned int R>
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unsigned int ChaCha_Policy<R>::GetAlignment() const
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{
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#if CRYPTOPP_SSE2_ASM_AVAILABLE && 0
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if (HasSSE2())
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return 16;
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else
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#endif
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return GetAlignmentOf<word32>();
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}
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template<unsigned int R>
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unsigned int ChaCha_Policy<R>::GetOptimalBlockSize() const
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{
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#if CRYPTOPP_SSE2_ASM_AVAILABLE && 0
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if (HasSSE2())
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return 4*BYTES_PER_ITERATION;
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else
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#endif
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return BYTES_PER_ITERATION;
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}
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template<unsigned int R>
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void ChaCha_Policy<R>::OperateKeystream(KeystreamOperation operation, byte *output, const byte *input, size_t iterationCount)
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{
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word32 x0, x1, x2, x3, x4, x5, x6, x7, x8, x9, x10, x11, x12, x13, x14, x15;
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while (iterationCount--)
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{
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x0 = m_state[0]; x1 = m_state[1]; x2 = m_state[2]; x3 = m_state[3];
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x4 = m_state[4]; x5 = m_state[5]; x6 = m_state[6]; x7 = m_state[7];
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x8 = m_state[8]; x9 = m_state[9]; x10 = m_state[10]; x11 = m_state[11];
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x12 = m_state[12]; x13 = m_state[13]; x14 = m_state[14]; x15 = m_state[15];
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for (int i = static_cast<int>(ROUNDS); i > 0; i -= 2)
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{
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CHACHA_QUARTER_ROUND(x0, x4, x8, x12);
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CHACHA_QUARTER_ROUND(x1, x5, x9, x13);
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CHACHA_QUARTER_ROUND(x2, x6, x10, x14);
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CHACHA_QUARTER_ROUND(x3, x7, x11, x15);
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CHACHA_QUARTER_ROUND(x0, x5, x10, x15);
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CHACHA_QUARTER_ROUND(x1, x6, x11, x12);
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CHACHA_QUARTER_ROUND(x2, x7, x8, x13);
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CHACHA_QUARTER_ROUND(x3, x4, x9, x14);
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}
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#undef CHACHA_OUTPUT
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#define CHACHA_OUTPUT(x){\
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CRYPTOPP_KEYSTREAM_OUTPUT_WORD(x, LITTLE_ENDIAN_ORDER, 0, x0 + m_state[0]);\
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CRYPTOPP_KEYSTREAM_OUTPUT_WORD(x, LITTLE_ENDIAN_ORDER, 1, x1 + m_state[1]);\
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CRYPTOPP_KEYSTREAM_OUTPUT_WORD(x, LITTLE_ENDIAN_ORDER, 2, x2 + m_state[2]);\
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CRYPTOPP_KEYSTREAM_OUTPUT_WORD(x, LITTLE_ENDIAN_ORDER, 3, x3 + m_state[3]);\
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CRYPTOPP_KEYSTREAM_OUTPUT_WORD(x, LITTLE_ENDIAN_ORDER, 4, x4 + m_state[4]);\
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CRYPTOPP_KEYSTREAM_OUTPUT_WORD(x, LITTLE_ENDIAN_ORDER, 5, x5 + m_state[5]);\
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CRYPTOPP_KEYSTREAM_OUTPUT_WORD(x, LITTLE_ENDIAN_ORDER, 6, x6 + m_state[6]);\
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CRYPTOPP_KEYSTREAM_OUTPUT_WORD(x, LITTLE_ENDIAN_ORDER, 7, x7 + m_state[7]);\
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CRYPTOPP_KEYSTREAM_OUTPUT_WORD(x, LITTLE_ENDIAN_ORDER, 8, x8 + m_state[8]);\
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CRYPTOPP_KEYSTREAM_OUTPUT_WORD(x, LITTLE_ENDIAN_ORDER, 9, x9 + m_state[9]);\
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CRYPTOPP_KEYSTREAM_OUTPUT_WORD(x, LITTLE_ENDIAN_ORDER, 10, x10 + m_state[10]);\
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CRYPTOPP_KEYSTREAM_OUTPUT_WORD(x, LITTLE_ENDIAN_ORDER, 11, x11 + m_state[11]);\
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CRYPTOPP_KEYSTREAM_OUTPUT_WORD(x, LITTLE_ENDIAN_ORDER, 12, x12 + m_state[12]);\
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CRYPTOPP_KEYSTREAM_OUTPUT_WORD(x, LITTLE_ENDIAN_ORDER, 13, x13 + m_state[13]);\
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CRYPTOPP_KEYSTREAM_OUTPUT_WORD(x, LITTLE_ENDIAN_ORDER, 14, x14 + m_state[14]);\
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CRYPTOPP_KEYSTREAM_OUTPUT_WORD(x, LITTLE_ENDIAN_ORDER, 15, x15 + m_state[15]);}
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#ifndef CRYPTOPP_DOXYGEN_PROCESSING
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CRYPTOPP_KEYSTREAM_OUTPUT_SWITCH(CHACHA_OUTPUT, BYTES_PER_ITERATION);
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#endif
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++m_state[12];
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m_state[13] += static_cast<word32>(m_state[12] == 0);
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}
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}
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template class ChaCha_Policy<8>;
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template class ChaCha_Policy<12>;
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template class ChaCha_Policy<20>;
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NAMESPACE_END
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