salsa.cpp

// salsa.cpp - written and placed in the public domain by Wei Dai

#include "pch.h"
#include "salsa.h"
#include "misc.h"
#include "argnames.h"
#include "cpu.h"

#if CRYPTOPP_BOOL_SSE2_INTRINSICS_AVAILABLE
#include <emmintrin.h>
#endif

NAMESPACE_BEGIN(CryptoPP)

void Salsa20_TestInstantiations()
{
        Salsa20::Encryption x;
}

void Salsa20_Policy::CipherSetKey(const NameValuePairs &params, const byte *key, size_t length)
{
        m_rounds = params.GetIntValueWithDefault(Name::Rounds(), 20);

        if (!(m_rounds == 8 || m_rounds == 12 || m_rounds == 20))
                throw InvalidRounds(StaticAlgorithmName(), m_rounds);

        // m_state is reordered for SSE2
        GetBlock<word32, LittleEndian, false> get1(key);
        get1(m_state[13])(m_state[10])(m_state[7])(m_state[4]);
        GetBlock<word32, LittleEndian, false> get2(key + length - 16);
        get2(m_state[15])(m_state[12])(m_state[9])(m_state[6]);

        // "expand 16-byte k" or "expand 32-byte k"
        m_state[0] = 0x61707865;
        m_state[1] = (length == 16) ? 0x3120646e : 0x3320646e;
        m_state[2] = (length == 16) ? 0x79622d36 : 0x79622d32;
        m_state[3] = 0x6b206574;
}

void Salsa20_Policy::CipherResynchronize(byte *keystreamBuffer, const byte *IV)
{
        GetBlock<word32, LittleEndian, false> get(IV);
        get(m_state[14])(m_state[11]);
        m_state[8] = m_state[5] = 0;
}

void Salsa20_Policy::SeekToIteration(lword iterationCount)
{
        m_state[8] = (word32)iterationCount;
        m_state[5] = (word32)SafeRightShift<32>(iterationCount);
}

#if CRYPTOPP_BOOL_X86 || CRYPTOPP_BOOL_X64
unsigned int Salsa20_Policy::GetAlignment() const
{
#if CRYPTOPP_BOOL_SSE2_INTRINSICS_AVAILABLE
        if (HasSSE2())
                return 16;
        else
#endif
                return 1;
}

unsigned int Salsa20_Policy::GetOptimalBlockSize() const
{
#if CRYPTOPP_BOOL_SSE2_INTRINSICS_AVAILABLE
        if (HasSSE2())
                return 4*BYTES_PER_ITERATION;
        else
#endif
                return BYTES_PER_ITERATION;
}
#endif

#if CRYPTOPP_BOOL_SSE2_INTRINSICS_AVAILABLE
static const __m128i s_maskLo32 = _mm_shuffle_epi32(_mm_cvtsi32_si128(-1), _MM_SHUFFLE(1, 0, 1, 0));
static const __m128i s_maskHi32 = _mm_slli_epi64(s_maskLo32, 32);
#endif

void Salsa20_Policy::OperateKeystream(KeystreamOperation operation, byte *output, const byte *input, size_t iterationCount)
{
        int i;
#if CRYPTOPP_BOOL_SSE2_INTRINSICS_AVAILABLE
        #define SSE2_QUARTER_ROUND(a, b, d, i)                          {\
                __m128i t = _mm_add_epi32(a, d);                                \
                b = _mm_xor_si128(b, _mm_slli_epi32(t, i));             \
                b = _mm_xor_si128(b, _mm_srli_epi32(t, 32-i));}

        if (HasSSE2())
        {
                __m128i *s = (__m128i *)m_state.data();

#if _MSC_VER > 1400 || (defined(_MSC_VER) && CRYPTOPP_BOOL_X86) || (CRYPTOPP_GCC_VERSION >= 40000 && CRYPTOPP_BOOL_X86)
                // This code triggers an internal compiler error on MSVC 2005 when compiling 
                // for x64 with optimizations on. hopefully it will get fixed in the next release.
                // A bug report has been submitted at http://connect.microsoft.com/VisualStudio/feedback/ViewFeedback.aspx?FeedbackID=274123
                // Also, GCC 3.4.4 generates incorrect code for x86 at -O2.
                // GCC 4.1.1 generates incorrect code for x64 at -O2
                if (iterationCount >= 4)
                {
                        __m128i ss[16];
                        ss[0] = _mm_shuffle_epi32(s[0], _MM_SHUFFLE(0, 0, 0, 0));
                        ss[1] = _mm_shuffle_epi32(s[0], _MM_SHUFFLE(1, 1, 1, 1));
                        ss[2] = _mm_shuffle_epi32(s[0], _MM_SHUFFLE(2, 2, 2, 2));
                        ss[3] = _mm_shuffle_epi32(s[0], _MM_SHUFFLE(3, 3, 3, 3));
                        ss[4] = _mm_shuffle_epi32(s[1], _MM_SHUFFLE(0, 0, 0, 0));
                        ss[6] = _mm_shuffle_epi32(s[1], _MM_SHUFFLE(2, 2, 2, 2));
                        ss[7] = _mm_shuffle_epi32(s[1], _MM_SHUFFLE(3, 3, 3, 3));
                        ss[9] = _mm_shuffle_epi32(s[2], _MM_SHUFFLE(1, 1, 1, 1));
                        ss[10] = _mm_shuffle_epi32(s[2], _MM_SHUFFLE(2, 2, 2, 2));
                        ss[11] = _mm_shuffle_epi32(s[2], _MM_SHUFFLE(3, 3, 3, 3));
                        ss[12] = _mm_shuffle_epi32(s[3], _MM_SHUFFLE(0, 0, 0, 0));
                        ss[13] = _mm_shuffle_epi32(s[3], _MM_SHUFFLE(1, 1, 1, 1));
                        ss[14] = _mm_shuffle_epi32(s[3], _MM_SHUFFLE(2, 2, 2, 2));
                        ss[15] = _mm_shuffle_epi32(s[3], _MM_SHUFFLE(3, 3, 3, 3));

                        do
                        {
                                word32 *countersLo = (word32*)&(ss[8]), *countersHi = (word32*)&(ss[5]);
                                for (i=0; i<4; i++)
                                {
                                        countersLo[i] = m_state[8];
                                        countersHi[i] = m_state[5];
                                        if (++m_state[8] == 0)
                                                ++m_state[5];
                                }

                                __m128i x0 = ss[0];
                                __m128i x1 = ss[1];
                                __m128i x2 = ss[2];
                                __m128i x3 = ss[3];
                                __m128i x4 = ss[4];
                                __m128i x5 = ss[5];
                                __m128i x6 = ss[6];
                                __m128i x7 = ss[7];
                                __m128i x8 = ss[8];
                                __m128i x9 = ss[9];
                                __m128i x10 = ss[10];
                                __m128i x11 = ss[11];
                                __m128i x12 = ss[12];
                                __m128i x13 = ss[13];
                                __m128i x14 = ss[14];
                                __m128i x15 = ss[15];

                                for (i=m_rounds; i>0; i-=2)
                                {
                                        #define QUARTER_ROUND(a, b, c, d)       \
                                                SSE2_QUARTER_ROUND(a, b, d, 7)  \
                                                SSE2_QUARTER_ROUND(b, c, a, 9)  \
                                                SSE2_QUARTER_ROUND(c, d, b, 13) \
                                                SSE2_QUARTER_ROUND(d, a, c, 18) 

                                        QUARTER_ROUND(x0, x4, x8, x12)
                                        QUARTER_ROUND(x1, x5, x9, x13)
                                        QUARTER_ROUND(x2, x6, x10, x14)
                                        QUARTER_ROUND(x3, x7, x11, x15)

                                        QUARTER_ROUND(x0, x13, x10, x7)
                                        QUARTER_ROUND(x1, x14, x11, x4)
                                        QUARTER_ROUND(x2, x15, x8, x5)
                                        QUARTER_ROUND(x3, x12, x9, x6)

                                        #undef QUARTER_ROUND
                                }

                                x0 = _mm_add_epi32(x0, ss[0]);
                                x1 = _mm_add_epi32(x1, ss[1]);
                                x2 = _mm_add_epi32(x2, ss[2]);
                                x3 = _mm_add_epi32(x3, ss[3]);
                                x4 = _mm_add_epi32(x4, ss[4]);
                                x5 = _mm_add_epi32(x5, ss[5]);
                                x6 = _mm_add_epi32(x6, ss[6]);
                                x7 = _mm_add_epi32(x7, ss[7]);
                                x8 = _mm_add_epi32(x8, ss[8]);
                                x9 = _mm_add_epi32(x9, ss[9]);
                                x10 = _mm_add_epi32(x10, ss[10]);
                                x11 = _mm_add_epi32(x11, ss[11]);
                                x12 = _mm_add_epi32(x12, ss[12]);
                                x13 = _mm_add_epi32(x13, ss[13]);
                                x14 = _mm_add_epi32(x14, ss[14]);
                                x15 = _mm_add_epi32(x15, ss[15]);

                                #define OUTPUT_4(x, a, b, c, d, e, f, g, h)     {\
                                        __m128i t0 = _mm_unpacklo_epi32(a, b);\
                                        __m128i t1 = _mm_unpacklo_epi32(c, d);\
                                        __m128i t2 = _mm_unpacklo_epi64(t0, t1);\
                                        CRYPTOPP_KEYSTREAM_OUTPUT_XMM(x, e, t2)\
                                        t2 = _mm_unpackhi_epi64(t0, t1);\
                                        CRYPTOPP_KEYSTREAM_OUTPUT_XMM(x, f, t2)\
                                        t0 = _mm_unpackhi_epi32(a, b);\
                                        t1 = _mm_unpackhi_epi32(c, d);\
                                        t2 = _mm_unpacklo_epi64(t0, t1);\
                                        CRYPTOPP_KEYSTREAM_OUTPUT_XMM(x, g, t2)\
                                        t2 = _mm_unpackhi_epi64(t0, t1);\
                                        CRYPTOPP_KEYSTREAM_OUTPUT_XMM(x, h, t2)}

                                #define SALSA_OUTPUT(x)         \
                                        OUTPUT_4(x, x0, x13, x10, x7, 0, 4, 8, 12)\
                                        OUTPUT_4(x, x4, x1, x14, x11, 1, 5, 9, 13)\
                                        OUTPUT_4(x, x8, x5, x2, x15, 2, 6, 10, 14)\
                                        OUTPUT_4(x, x12, x9, x6, x3, 3, 7, 11, 15)

                                CRYPTOPP_KEYSTREAM_OUTPUT_SWITCH(SALSA_OUTPUT, 4*BYTES_PER_ITERATION)

                                #undef SALSA_OUTPUT
                        } while ((iterationCount-=4) >= 4);
                }
#endif

                if (!IsP4()) while (iterationCount)
                {
                        --iterationCount;
                        __m128i x0 = s[0];
                        __m128i x1 = s[1];
                        __m128i x2 = s[2];
                        __m128i x3 = s[3];

                        for (i=m_rounds; i>0; i-=2)
                        {
                                SSE2_QUARTER_ROUND(x0, x1, x3, 7)
                                SSE2_QUARTER_ROUND(x1, x2, x0, 9)
                                SSE2_QUARTER_ROUND(x2, x3, x1, 13)
                                SSE2_QUARTER_ROUND(x3, x0, x2, 18)

                                x1 = _mm_shuffle_epi32(x1, _MM_SHUFFLE(2, 1, 0, 3));
                                x2 = _mm_shuffle_epi32(x2, _MM_SHUFFLE(1, 0, 3, 2));
                                x3 = _mm_shuffle_epi32(x3, _MM_SHUFFLE(0, 3, 2, 1));

                                SSE2_QUARTER_ROUND(x0, x3, x1, 7)
                                SSE2_QUARTER_ROUND(x3, x2, x0, 9)
                                SSE2_QUARTER_ROUND(x2, x1, x3, 13)
                                SSE2_QUARTER_ROUND(x1, x0, x2, 18)

                                x1 = _mm_shuffle_epi32(x1, _MM_SHUFFLE(0, 3, 2, 1));
                                x2 = _mm_shuffle_epi32(x2, _MM_SHUFFLE(1, 0, 3, 2));
                                x3 = _mm_shuffle_epi32(x3, _MM_SHUFFLE(2, 1, 0, 3));
                        }

                        x0 = _mm_add_epi32(x0, s[0]);
                        x1 = _mm_add_epi32(x1, s[1]);
                        x2 = _mm_add_epi32(x2, s[2]);
                        x3 = _mm_add_epi32(x3, s[3]);

                        if (++m_state[8] == 0)
                                ++m_state[5];

                        __m128i k02 = _mm_or_si128(_mm_slli_epi64(x0, 32), _mm_srli_epi64(x3, 32));
                        k02 = _mm_shuffle_epi32(k02, _MM_SHUFFLE(0, 1, 2, 3));
                        __m128i k13 = _mm_or_si128(_mm_slli_epi64(x1, 32), _mm_srli_epi64(x0, 32));
                        k13 = _mm_shuffle_epi32(k13, _MM_SHUFFLE(0, 1, 2, 3));
                        __m128i k20 = _mm_or_si128(_mm_and_si128(x2, s_maskLo32), _mm_and_si128(x1, s_maskHi32));
                        __m128i k31 = _mm_or_si128(_mm_and_si128(x3, s_maskLo32), _mm_and_si128(x2, s_maskHi32));

                        __m128i k0 = _mm_unpackhi_epi64(k02, k20);
                        __m128i k1 = _mm_unpackhi_epi64(k13, k31);
                        __m128i k2 = _mm_unpacklo_epi64(k20, k02);
                        __m128i k3 = _mm_unpacklo_epi64(k31, k13);

                        #define SSE2_OUTPUT(x)  {\
                                CRYPTOPP_KEYSTREAM_OUTPUT_XMM(x, 0, k0)\
                                CRYPTOPP_KEYSTREAM_OUTPUT_XMM(x, 1, k1)\
                                CRYPTOPP_KEYSTREAM_OUTPUT_XMM(x, 2, k2)\
                                CRYPTOPP_KEYSTREAM_OUTPUT_XMM(x, 3, k3)}

                        CRYPTOPP_KEYSTREAM_OUTPUT_SWITCH(SSE2_OUTPUT, BYTES_PER_ITERATION);
                }
        }
#endif

        word32 x0, x1, x2, x3, x4, x5, x6, x7, x8, x9, x10, x11, x12, x13, x14, x15;

        while (iterationCount--)
        {
                x0 = m_state[0];
                x1 = m_state[1];
                x2 = m_state[2];
                x3 = m_state[3];
                x4 = m_state[4];
                x5 = m_state[5];
                x6 = m_state[6];
                x7 = m_state[7];
                x8 = m_state[8];
                x9 = m_state[9];
                x10 = m_state[10];
                x11 = m_state[11];
                x12 = m_state[12];
                x13 = m_state[13];
                x14 = m_state[14];
                x15 = m_state[15];

                for (i=m_rounds; i>0; i-=2)
                {
                        #define QUARTER_ROUND(a, b, c, d)       \
                                b = b ^ rotlFixed(a + d, 7);    \
                                c = c ^ rotlFixed(b + a, 9);    \
                                d = d ^ rotlFixed(c + b, 13);   \
                                a = a ^ rotlFixed(d + c, 18);

                        QUARTER_ROUND(x0, x4, x8, x12)
                        QUARTER_ROUND(x1, x5, x9, x13)
                        QUARTER_ROUND(x2, x6, x10, x14)
                        QUARTER_ROUND(x3, x7, x11, x15)

                        QUARTER_ROUND(x0, x13, x10, x7)
                        QUARTER_ROUND(x1, x14, x11, x4)
                        QUARTER_ROUND(x2, x15, x8, x5)
                        QUARTER_ROUND(x3, x12, x9, x6)
                }

                #define SALSA_OUTPUT(x) {\
                        CRYPTOPP_KEYSTREAM_OUTPUT_WORD(x, LITTLE_ENDIAN_ORDER, 0, x0 + m_state[0]);\
                        CRYPTOPP_KEYSTREAM_OUTPUT_WORD(x, LITTLE_ENDIAN_ORDER, 1, x13 + m_state[13]);\
                        CRYPTOPP_KEYSTREAM_OUTPUT_WORD(x, LITTLE_ENDIAN_ORDER, 2, x10 + m_state[10]);\
                        CRYPTOPP_KEYSTREAM_OUTPUT_WORD(x, LITTLE_ENDIAN_ORDER, 3, x7 + m_state[7]);\
                        CRYPTOPP_KEYSTREAM_OUTPUT_WORD(x, LITTLE_ENDIAN_ORDER, 4, x4 + m_state[4]);\
                        CRYPTOPP_KEYSTREAM_OUTPUT_WORD(x, LITTLE_ENDIAN_ORDER, 5, x1 + m_state[1]);\
                        CRYPTOPP_KEYSTREAM_OUTPUT_WORD(x, LITTLE_ENDIAN_ORDER, 6, x14 + m_state[14]);\
                        CRYPTOPP_KEYSTREAM_OUTPUT_WORD(x, LITTLE_ENDIAN_ORDER, 7, x11 + m_state[11]);\
                        CRYPTOPP_KEYSTREAM_OUTPUT_WORD(x, LITTLE_ENDIAN_ORDER, 8, x8 + m_state[8]);\
                        CRYPTOPP_KEYSTREAM_OUTPUT_WORD(x, LITTLE_ENDIAN_ORDER, 9, x5 + m_state[5]);\
                        CRYPTOPP_KEYSTREAM_OUTPUT_WORD(x, LITTLE_ENDIAN_ORDER, 10, x2 + m_state[2]);\
                        CRYPTOPP_KEYSTREAM_OUTPUT_WORD(x, LITTLE_ENDIAN_ORDER, 11, x15 + m_state[15]);\
                        CRYPTOPP_KEYSTREAM_OUTPUT_WORD(x, LITTLE_ENDIAN_ORDER, 12, x12 + m_state[12]);\
                        CRYPTOPP_KEYSTREAM_OUTPUT_WORD(x, LITTLE_ENDIAN_ORDER, 13, x9 + m_state[9]);\
                        CRYPTOPP_KEYSTREAM_OUTPUT_WORD(x, LITTLE_ENDIAN_ORDER, 14, x6 + m_state[6]);\
                        CRYPTOPP_KEYSTREAM_OUTPUT_WORD(x, LITTLE_ENDIAN_ORDER, 15, x3 + m_state[3]);}

#ifndef CRYPTOPP_DOXYGEN_PROCESSING
                CRYPTOPP_KEYSTREAM_OUTPUT_SWITCH(SALSA_OUTPUT, BYTES_PER_ITERATION);
#endif

                if (++m_state[8] == 0)
                        ++m_state[5];
        }
}       // see comment above if an internal compiler error occurs here

NAMESPACE_END

---