// sm4.cpp - written and placed in the public domain by Jeffrey Walton and Han Lulu
//
//    We understand future ARMv8 enhancements are supposed
//    to include SM3 and SM4 related instructions so the function
//    is stubbed for an eventual SM4_Round_ARMV8.

#include "pch.h"
#include "config.h"

#include "sm4.h"
#include "misc.h"
#include "cpu.h"

ANONYMOUS_NAMESPACE_BEGIN

using CryptoPP::byte;
using CryptoPP::word32;
using CryptoPP::rotlConstant;

const byte S[256] =
{
    0xD6, 0x90, 0xE9, 0xFE, 0xCC, 0xE1, 0x3D, 0xB7, 0x16, 0xB6, 0x14, 0xC2, 0x28, 0xFB, 0x2C, 0x05,
    0x2B, 0x67, 0x9A, 0x76, 0x2A, 0xBE, 0x04, 0xC3, 0xAA, 0x44, 0x13, 0x26, 0x49, 0x86, 0x06, 0x99,
    0x9C, 0x42, 0x50, 0xF4, 0x91, 0xEF, 0x98, 0x7A, 0x33, 0x54, 0x0B, 0x43, 0xED, 0xCF, 0xAC, 0x62,
    0xE4, 0xB3, 0x1C, 0xA9, 0xC9, 0x08, 0xE8, 0x95, 0x80, 0xDF, 0x94, 0xFA, 0x75, 0x8F, 0x3F, 0xA6,
    0x47, 0x07, 0xA7, 0xFC, 0xF3, 0x73, 0x17, 0xBA, 0x83, 0x59, 0x3C, 0x19, 0xE6, 0x85, 0x4F, 0xA8,
    0x68, 0x6B, 0x81, 0xB2, 0x71, 0x64, 0xDA, 0x8B, 0xF8, 0xEB, 0x0F, 0x4B, 0x70, 0x56, 0x9D, 0x35,
    0x1E, 0x24, 0x0E, 0x5E, 0x63, 0x58, 0xD1, 0xA2, 0x25, 0x22, 0x7C, 0x3B, 0x01, 0x21, 0x78, 0x87,
    0xD4, 0x00, 0x46, 0x57, 0x9F, 0xD3, 0x27, 0x52, 0x4C, 0x36, 0x02, 0xE7, 0xA0, 0xC4, 0xC8, 0x9E,
    0xEA, 0xBF, 0x8A, 0xD2, 0x40, 0xC7, 0x38, 0xB5, 0xA3, 0xF7, 0xF2, 0xCE, 0xF9, 0x61, 0x15, 0xA1,
    0xE0, 0xAE, 0x5D, 0xA4, 0x9B, 0x34, 0x1A, 0x55, 0xAD, 0x93, 0x32, 0x30, 0xF5, 0x8C, 0xB1, 0xE3,
    0x1D, 0xF6, 0xE2, 0x2E, 0x82, 0x66, 0xCA, 0x60, 0xC0, 0x29, 0x23, 0xAB, 0x0D, 0x53, 0x4E, 0x6F,
    0xD5, 0xDB, 0x37, 0x45, 0xDE, 0xFD, 0x8E, 0x2F, 0x03, 0xFF, 0x6A, 0x72, 0x6D, 0x6C, 0x5B, 0x51,
    0x8D, 0x1B, 0xAF, 0x92, 0xBB, 0xDD, 0xBC, 0x7F, 0x11, 0xD9, 0x5C, 0x41, 0x1F, 0x10, 0x5A, 0xD8,
    0x0A, 0xC1, 0x31, 0x88, 0xA5, 0xCD, 0x7B, 0xBD, 0x2D, 0x74, 0xD0, 0x12, 0xB8, 0xE5, 0xB4, 0xB0,
    0x89, 0x69, 0x97, 0x4A, 0x0C, 0x96, 0x77, 0x7E, 0x65, 0xB9, 0xF1, 0x09, 0xC5, 0x6E, 0xC6, 0x84,
    0x18, 0xF0, 0x7D, 0xEC, 0x3A, 0xDC, 0x4D, 0x20, 0x79, 0xEE, 0x5F, 0x3E, 0xD7, 0xCB, 0x39, 0x48
};

const word32 CK[32] =
{
    0x00070E15, 0x1C232A31, 0x383F464D, 0x545B6269,
    0x70777E85, 0x8C939AA1, 0xA8AFB6BD, 0xC4CBD2D9,
    0xE0E7EEF5, 0xFC030A11, 0x181F262D, 0x343B4249,
    0x50575E65, 0x6C737A81, 0x888F969D, 0xA4ABB2B9,
    0xC0C7CED5, 0xDCE3EAF1, 0xF8FF060D, 0x141B2229,
    0x30373E45, 0x4C535A61, 0x686F767D, 0x848B9299,
    0xA0A7AEB5, 0xBCC3CAD1, 0xD8DFE6ED, 0xF4FB0209,
    0x10171E25, 0x2C333A41, 0x484F565D, 0x646B7279
};

inline word32 SM4_H(word32 x)
{
    return (S[GETBYTE(x, 3)] << 24) | (S[GETBYTE(x, 2)] << 16) | (S[GETBYTE(x, 1)] << 8) | (S[GETBYTE(x, 0)]);
}

inline word32 SM4_G(word32 x)
{
    const word32 t = SM4_H(x);
    return t ^ rotlConstant<13>(t) ^ rotlConstant<23>(t);
}

inline word32 SM4_F(word32 x)
{
    const word32 t = SM4_H(x);
    return t ^ rotlConstant<2>(t) ^ rotlConstant<10>(t) ^ rotlConstant<18>(t) ^ rotlConstant<24>(t);
}

template <unsigned int R, bool FWD>
inline void SM4_Round(word32 wspace[4], const word32 rkeys[32])
{
    if (FWD)
    {
        wspace[0] ^= SM4_F(wspace[1] ^ wspace[2] ^ wspace[3] ^ rkeys[R+0]);
        wspace[1] ^= SM4_F(wspace[0] ^ wspace[2] ^ wspace[3] ^ rkeys[R+1]);
        wspace[2] ^= SM4_F(wspace[0] ^ wspace[1] ^ wspace[3] ^ rkeys[R+2]);
        wspace[3] ^= SM4_F(wspace[0] ^ wspace[1] ^ wspace[2] ^ rkeys[R+3]);
    }
    else
    {
        wspace[0] ^= SM4_F(wspace[1] ^ wspace[2] ^ wspace[3] ^ rkeys[R-0]);
        wspace[1] ^= SM4_F(wspace[0] ^ wspace[2] ^ wspace[3] ^ rkeys[R-1]);
        wspace[2] ^= SM4_F(wspace[0] ^ wspace[1] ^ wspace[3] ^ rkeys[R-2]);
        wspace[3] ^= SM4_F(wspace[0] ^ wspace[1] ^ wspace[2] ^ rkeys[R-3]);
    }
}

ANONYMOUS_NAMESPACE_END

NAMESPACE_BEGIN(CryptoPP)

void SM4::Base::UncheckedSetKey(const byte *userKey, unsigned int keyLength, const NameValuePairs &params)
{
    CRYPTOPP_ASSERT(keyLength == 16);
    CRYPTOPP_UNUSED(params);

    m_rkeys.New(32);
    m_wspace.New(5);

    GetUserKey(BIG_ENDIAN_ORDER, m_wspace.begin(), 4, userKey, keyLength);
    m_wspace[0] ^= 0xa3b1bac6; m_wspace[1] ^= 0x56aa3350;
    m_wspace[2] ^= 0x677d9197; m_wspace[3] ^= 0xb27022dc;

    size_t i=0;
    do
    {
        m_rkeys[i] = (m_wspace[0] ^= SM4_G(m_wspace[1] ^ m_wspace[2] ^ m_wspace[3] ^ CK[i])); i++;
        m_rkeys[i] = (m_wspace[1] ^= SM4_G(m_wspace[2] ^ m_wspace[3] ^ m_wspace[0] ^ CK[i])); i++;
        m_rkeys[i] = (m_wspace[2] ^= SM4_G(m_wspace[3] ^ m_wspace[0] ^ m_wspace[1] ^ CK[i])); i++;
        m_rkeys[i] = (m_wspace[3] ^= SM4_G(m_wspace[0] ^ m_wspace[1] ^ m_wspace[2] ^ CK[i])); i++;
    }
    while (i < 32);
}

void SM4::Enc::ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byte *outBlock) const
{
    // Reverse bytes on LittleEndian; align pointer on BigEndian
    typedef GetBlock<word32, BigEndian, false> InBlock;
    InBlock iblk(inBlock); iblk(m_wspace[0])(m_wspace[1])(m_wspace[2])(m_wspace[3]);

    // Timing attack countermeasure, see comments in Rijndael for more details.
    // The hardening does not materially affect benchmarks. SM4 runs at
    // 30.5 cpb on a Core i5 Skylake with and without the code below.
    const int cacheLineSize = GetCacheLineSize();
    volatile word32 _u = 0;
    word32 u = _u;

    for (unsigned int i=0; i<sizeof(S); i+=cacheLineSize)
        u |= *(const word32 *)(void*)(S+i);
    m_wspace[4] = u;

    SM4_Round< 0, true>(m_wspace, m_rkeys);
    SM4_Round< 4, true>(m_wspace, m_rkeys);
    SM4_Round< 8, true>(m_wspace, m_rkeys);
    SM4_Round<12, true>(m_wspace, m_rkeys);
    SM4_Round<16, true>(m_wspace, m_rkeys);
    SM4_Round<20, true>(m_wspace, m_rkeys);
    SM4_Round<24, true>(m_wspace, m_rkeys);
    SM4_Round<28, true>(m_wspace, m_rkeys);

    // Reverse bytes on LittleEndian; align pointer on BigEndian
    typedef PutBlock<word32, BigEndian, false> OutBlock;
    OutBlock oblk(xorBlock, outBlock); oblk(m_wspace[3])(m_wspace[2])(m_wspace[1])(m_wspace[0]);
}

void SM4::Dec::ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byte *outBlock) const
{
    // Reverse bytes on LittleEndian; align pointer on BigEndian
    typedef GetBlock<word32, BigEndian, false> InBlock;
    InBlock iblk(inBlock); iblk(m_wspace[0])(m_wspace[1])(m_wspace[2])(m_wspace[3]);

    // Timing attack countermeasure, see comments in Rijndael for more details.
    // The hardening does not materially affect benchmarks. SM4 runs at
    // 30.5 cpb on a Core i5 Skylake with and without the code below.
    const int cacheLineSize = GetCacheLineSize();
    volatile word32 _u = 0;
    word32 u = _u;

    for (unsigned int i=0; i<sizeof(S); i+=cacheLineSize)
        u |= *(const word32 *)(void*)(S+i);
    m_wspace[4] = u;

    SM4_Round<31, false>(m_wspace, m_rkeys);
    SM4_Round<27, false>(m_wspace, m_rkeys);
    SM4_Round<23, false>(m_wspace, m_rkeys);
    SM4_Round<19, false>(m_wspace, m_rkeys);
    SM4_Round<15, false>(m_wspace, m_rkeys);
    SM4_Round<11, false>(m_wspace, m_rkeys);
    SM4_Round< 7, false>(m_wspace, m_rkeys);
    SM4_Round< 3, false>(m_wspace, m_rkeys);

    // Reverse bytes on LittleEndian; align pointer on BigEndian
    typedef PutBlock<word32, BigEndian, false> OutBlock;
    OutBlock oblk(xorBlock, outBlock); oblk(m_wspace[3])(m_wspace[2])(m_wspace[1])(m_wspace[0]);
}

NAMESPACE_END
