text: // simon.h - written and placed in the public domain by Jeffrey Walton
  
  #include "pch.h"
  #include "config.h"
  
  #include "simon.h"
  #include "misc.h"
  #include "cpu.h"
  
  // Uncomment for benchmarking C++ against SSE or NEON.
  // Do so in both simon.cpp and simon-simd.cpp.
  // #undef CRYPTOPP_SSSE3_AVAILABLE
  // #undef CRYPTOPP_SSE41_AVAILABLE
  // #undef CRYPTOPP_ARM_NEON_AVAILABLE
  
  ANONYMOUS_NAMESPACE_BEGIN
  
  using CryptoPP::word32;
  using CryptoPP::word64;
  using CryptoPP::rotlConstant;
  using CryptoPP::rotrConstant;
  
  /// \brief Round transformation helper
  /// \tparam W word type
  /// \param v value
  template <class W>
  inline W f(const W v)
  {
      return (rotlConstant<1>(v) & rotlConstant<8>(v)) ^ rotlConstant<2>(v);
  }
  
  /// \brief Round transformation
  /// \tparam W word type
  /// \param x value
  /// \param y value
  /// \param k value
  /// \param l value
  template <class W>
  inline void R2(W& x, W& y, const W k, const W l)
  {
      y ^= f(x); y ^= k;
      x ^= f(y); x ^= l;
  }
  
  /// \brief Forward transformation
  /// \tparam W word type
  /// \tparam R number of rounds
  /// \param c output array
  /// \param p input array
  /// \param k subkey array
  template <class W, unsigned int R>
  inline void SIMON_Encrypt(W c[2], const W p[2], const W k[R])
  {
      c[0]=p[0]; c[1]=p[1];
  
      for (int i = 0; i < static_cast<int>(R-1); i += 2)
          R2(c[0], c[1], k[i], k[i + 1]);
  
      if (R & 1)
      {
          c[1] ^= f(c[0]); c[1] ^= k[R-1];
          W t = c[0]; c[0] = c[1]; c[1] = t;
      }
  }
  
  /// \brief Reverse transformation
  /// \tparam W word type
  /// \tparam R number of rounds
  /// \param p output array
  /// \param c input array
  /// \param k subkey array
  template <class W, unsigned int R>
  inline void SIMON_Decrypt(W p[2], const W c[2], const W k[R])
  {
      p[0]=c[0]; p[1]=c[1];
      unsigned int rounds = R;
  
      if (R & 1)
      {
          const W t = p[1]; p[1] = p[0]; p[0] = t;
          p[1] ^= k[R - 1]; p[1] ^= f(p[0]);
          rounds--;
      }
  
      for (int i = static_cast<int>(rounds - 2); i >= 0; i -= 2)
          R2(p[1], p[0], k[i + 1], k[i]);
  }
  
  /// \brief Subkey generation function
  /// \details Used for SIMON-64 with 96-bit key and 42 rounds. A template was
  ///   not worthwhile because all instantiations would need specialization.
  /// \param key empty subkey array
  /// \param k user key array
  inline void SIMON64_ExpandKey_3W(word32 key[42], const word32 k[3])
  {
      const word32 c = 0xfffffffc;
      word64 z = W64LIT(0x7369f885192c0ef5);
  
      key[0] = k[2]; key[1] = k[1]; key[2] = k[0];
      for (size_t i = 3; i<42; ++i)
      {
          key[i] = c ^ (z & 1) ^ key[i - 3] ^ rotrConstant<3>(key[i - 1]) ^ rotrConstant<4>(key[i - 1]);
          z >>= 1;
      }
  }
  
  /// \brief Subkey generation function
  /// \details Used for SIMON-64 with 128-bit key and 44 rounds. A template was
  ///   not worthwhile because all instantiations would need specialization.
  /// \param key empty subkey array
  /// \param k user key array
  inline void SIMON64_ExpandKey_4W(word32 key[44], const word32 k[4])
  {
      const word32 c = 0xfffffffc;
      word64 z = W64LIT(0xfc2ce51207a635db);
  
      key[0] = k[3]; key[1] = k[2]; key[2] = k[1]; key[3] = k[0];
      for (size_t i = 4; i<44; ++i)
      {
          key[i] = c ^ (z & 1) ^ key[i - 4] ^ rotrConstant<3>(key[i - 1]) ^ key[i - 3] ^ rotrConstant<4>(key[i - 1]) ^ rotrConstant<1>(key[i - 3]);
          z >>= 1;
      }
  }
  
  /// \brief Subkey generation function
  /// \details Used for SIMON-128 with 128-bit key and 68 rounds. A template was
  ///   not worthwhile because all instantiations would need specialization.
  /// \param key empty subkey array
  /// \param k user key array
  inline void SIMON128_ExpandKey_2W(word64 key[68], const word64 k[2])
  {
      const word64 c = W64LIT(0xfffffffffffffffc);
      word64 z = W64LIT(0x7369f885192c0ef5);
  
      key[0] = k[1]; key[1] = k[0];
      for (size_t i=2; i<66; ++i)
      {
          key[i] = c ^ (z & 1) ^ key[i - 2] ^ rotrConstant<3>(key[i - 1]) ^ rotrConstant<4>(key[i - 1]);
          z>>=1;
      }
  
      key[66] = c ^ 1 ^ key[64] ^ rotrConstant<3>(key[65]) ^ rotrConstant<4>(key[65]);
      key[67] = c^key[65] ^ rotrConstant<3>(key[66]) ^ rotrConstant<4>(key[66]);
  }
  
  /// \brief Subkey generation function
  /// \details Used for SIMON-128 with 192-bit key and 69 rounds. A template was
  ///   not worthwhile because all instantiations would need specialization.
  /// \param key empty subkey array
  /// \param k user key array
  inline void SIMON128_ExpandKey_3W(word64 key[69], const word64 k[3])
  {
      const word64 c = W64LIT(0xfffffffffffffffc);
      word64 z = W64LIT(0xfc2ce51207a635db);
  
      key[0]=k[2]; key[1]=k[1]; key[2]=k[0];
      for (size_t i=3; i<67; ++i)
      {
          key[i] = c ^ (z & 1) ^ key[i - 3] ^ rotrConstant<3>(key[i - 1]) ^ rotrConstant<4>(key[i - 1]);
          z>>=1;
      }
  
      key[67] = c^key[64] ^ rotrConstant<3>(key[66]) ^ rotrConstant<4>(key[66]);
      key[68] = c ^ 1 ^ key[65] ^ rotrConstant<3>(key[67]) ^ rotrConstant<4>(key[67]);
  }
  
  /// \brief Subkey generation function
  /// \details Used for SIMON-128 with 256-bit key and 72 rounds. A template was
  ///   not worthwhile because all instantiations would need specialization.
  /// \param key empty subkey array
  /// \param k user key array
  inline void SIMON128_ExpandKey_4W(word64 key[72], const word64 k[4])
  {
      const word64 c = W64LIT(0xfffffffffffffffc);
      word64 z = W64LIT(0xfdc94c3a046d678b);
  
      key[0]=k[3]; key[1]=k[2]; key[2]=k[1]; key[3]=k[0];
      for (size_t i=4; i<68; ++i)
      {
          key[i] = c ^ (z & 1) ^ key[i - 4] ^ rotrConstant<3>(key[i - 1]) ^ key[i - 3] ^ rotrConstant<4>(key[i - 1]) ^ rotrConstant<1>(key[i - 3]);
          z>>=1;
      }
  
      key[68] = c^key[64] ^ rotrConstant<3>(key[67]) ^ key[65] ^ rotrConstant<4>(key[67]) ^ rotrConstant<1>(key[65]);
      key[69] = c ^ 1 ^ key[65] ^ rotrConstant<3>(key[68]) ^ key[66] ^ rotrConstant<4>(key[68]) ^ rotrConstant<1>(key[66]);
      key[70] = c^key[66] ^ rotrConstant<3>(key[69]) ^ key[67] ^ rotrConstant<4>(key[69]) ^ rotrConstant<1>(key[67]);
      key[71] = c^key[67] ^ rotrConstant<3>(key[70]) ^ key[68] ^ rotrConstant<4>(key[70]) ^ rotrConstant<1>(key[68]);
  }
  
  ANONYMOUS_NAMESPACE_END
  
  ///////////////////////////////////////////////////////////
  
  NAMESPACE_BEGIN(CryptoPP)
  
  #if (CRYPTOPP_ARM_NEON_AVAILABLE)
  extern size_t SIMON64_Enc_AdvancedProcessBlocks_NEON(const word32* subKeys, size_t rounds,
      const byte *inBlocks, const byte *xorBlocks, byte *outBlocks, size_t length, word32 flags);
  
  extern size_t SIMON64_Dec_AdvancedProcessBlocks_NEON(const word32* subKeys, size_t rounds,
      const byte *inBlocks, const byte *xorBlocks, byte *outBlocks, size_t length, word32 flags);
  #endif
  
  #if (CRYPTOPP_ARM_NEON_AVAILABLE)
  extern size_t SIMON128_Enc_AdvancedProcessBlocks_NEON(const word64* subKeys, size_t rounds,
      const byte *inBlocks, const byte *xorBlocks, byte *outBlocks, size_t length, word32 flags);
  
  extern size_t SIMON128_Dec_AdvancedProcessBlocks_NEON(const word64* subKeys, size_t rounds,
      const byte *inBlocks, const byte *xorBlocks, byte *outBlocks, size_t length, word32 flags);
  #endif
  
  #if defined(CRYPTOPP_SSE41_AVAILABLE)
  extern size_t SIMON64_Enc_AdvancedProcessBlocks_SSE41(const word32* subKeys, size_t rounds,
      const byte *inBlocks, const byte *xorBlocks, byte *outBlocks, size_t length, word32 flags);
  
  extern size_t SIMON64_Dec_AdvancedProcessBlocks_SSE41(const word32* subKeys, size_t rounds,
      const byte *inBlocks, const byte *xorBlocks, byte *outBlocks, size_t length, word32 flags);
  #endif
  
  #if defined(CRYPTOPP_SSSE3_AVAILABLE)
  extern size_t SIMON128_Enc_AdvancedProcessBlocks_SSSE3(const word64* subKeys, size_t rounds,
      const byte *inBlocks, const byte *xorBlocks, byte *outBlocks, size_t length, word32 flags);
  
  extern size_t SIMON128_Dec_AdvancedProcessBlocks_SSSE3(const word64* subKeys, size_t rounds,
      const byte *inBlocks, const byte *xorBlocks, byte *outBlocks, size_t length, word32 flags);
  #endif
  
  void SIMON64::Base::UncheckedSetKey(const byte *userKey, unsigned int keyLength, const NameValuePairs &params)
  {
      CRYPTOPP_ASSERT(keyLength == 12 || keyLength == 16);
      CRYPTOPP_UNUSED(params);
  
      // Building the key schedule table requires {3,4} words workspace.
      // Encrypting and decrypting requires 4 words workspace.
      m_kwords = keyLength/sizeof(word32);
      m_wspace.New(4U);
  
      // Do the endian gyrations from the paper and align pointers
      typedef GetBlock<word32, LittleEndian, false> KeyBlock;
      KeyBlock kblk(userKey);
  
      switch (m_kwords)
      {
      case 3:
          m_rkeys.New((m_rounds = 42));
          kblk(m_wspace[2])(m_wspace[1])(m_wspace[0]);
          SIMON64_ExpandKey_3W(m_rkeys, m_wspace);
          break;
      case 4:
          m_rkeys.New((m_rounds = 44));
          kblk(m_wspace[3])(m_wspace[2])(m_wspace[1])(m_wspace[0]);
          SIMON64_ExpandKey_4W(m_rkeys, m_wspace);
          break;
      default:
          CRYPTOPP_ASSERT(0);;
      }
  }
  
  void SIMON64::Enc::ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byte *outBlock) const
  {
      // Do the endian gyrations from the paper and align pointers
      typedef GetBlock<word32, LittleEndian, false> InBlock;
      InBlock iblk(inBlock); iblk(m_wspace[1])(m_wspace[0]);
  
      switch (m_rounds)
      {
      case 42:
          SIMON_Encrypt<word32, 42>(m_wspace+2, m_wspace+0, m_rkeys);
          break;
      case 44:
          SIMON_Encrypt<word32, 44>(m_wspace+2, m_wspace+0, m_rkeys);
          break;
      default:
          CRYPTOPP_ASSERT(0);;
      }
  
      // Do the endian gyrations from the paper and align pointers
      typedef PutBlock<word32, LittleEndian, false> OutBlock;
      OutBlock oblk(xorBlock, outBlock); oblk(m_wspace[3])(m_wspace[2]);
  }
  
  void SIMON64::Dec::ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byte *outBlock) const
  {
      // Do the endian gyrations from the paper and align pointers
      typedef GetBlock<word32, LittleEndian, false> InBlock;
      InBlock iblk(inBlock); iblk(m_wspace[1])(m_wspace[0]);
  
      switch (m_rounds)
      {
      case 42:
          SIMON_Decrypt<word32, 42>(m_wspace+2, m_wspace+0, m_rkeys);
          break;
      case 44:
          SIMON_Decrypt<word32, 44>(m_wspace+2, m_wspace+0, m_rkeys);
          break;
      default:
          CRYPTOPP_ASSERT(0);;
      }
  
      // Do the endian gyrations from the paper and align pointers
      typedef PutBlock<word32, LittleEndian, false> OutBlock;
      OutBlock oblk(xorBlock, outBlock); oblk(m_wspace[3])(m_wspace[2]);
  }
  
  ///////////////////////////////////////////////////////////
  
  void SIMON128::Base::UncheckedSetKey(const byte *userKey, unsigned int keyLength, const NameValuePairs &params)
  {
      CRYPTOPP_ASSERT(keyLength == 16 || keyLength == 24 || keyLength == 32);
      CRYPTOPP_UNUSED(params);
  
      // Building the key schedule table requires {2,3,4} words workspace.
      // Encrypting and decrypting requires 4 words workspace.
      m_kwords = keyLength/sizeof(word64);
      m_wspace.New(4U);
  
      // Do the endian gyrations from the paper and align pointers
      typedef GetBlock<word64, LittleEndian, false> KeyBlock;
      KeyBlock kblk(userKey);
  
      switch (m_kwords)
      {
      case 2:
          m_rkeys.New((m_rounds = 68));
          kblk(m_wspace[1])(m_wspace[0]);
          SIMON128_ExpandKey_2W(m_rkeys, m_wspace);
          break;
      case 3:
          m_rkeys.New((m_rounds = 69));
          kblk(m_wspace[2])(m_wspace[1])(m_wspace[0]);
          SIMON128_ExpandKey_3W(m_rkeys, m_wspace);
          break;
      case 4:
          m_rkeys.New((m_rounds = 72));
          kblk(m_wspace[3])(m_wspace[2])(m_wspace[1])(m_wspace[0]);
          SIMON128_ExpandKey_4W(m_rkeys, m_wspace);
          break;
      default:
          CRYPTOPP_ASSERT(0);;
      }
  }
  
  void SIMON128::Enc::ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byte *outBlock) const
  {
      // Do the endian gyrations from the paper and align pointers
      typedef GetBlock<word64, LittleEndian, false> InBlock;
      InBlock iblk(inBlock); iblk(m_wspace[1])(m_wspace[0]);
  
      switch (m_rounds)
      {
      case 68:
          SIMON_Encrypt<word64, 68>(m_wspace+2, m_wspace+0, m_rkeys);
          break;
      case 69:
          SIMON_Encrypt<word64, 69>(m_wspace+2, m_wspace+0, m_rkeys);
          break;
      case 72:
          SIMON_Encrypt<word64, 72>(m_wspace+2, m_wspace+0, m_rkeys);
          break;
      default:
          CRYPTOPP_ASSERT(0);;
      }
  
      // Do the endian gyrations from the paper and align pointers
      typedef PutBlock<word64, LittleEndian, false> OutBlock;
      OutBlock oblk(xorBlock, outBlock); oblk(m_wspace[3])(m_wspace[2]);
  }
  
  void SIMON128::Dec::ProcessAndXorBlock(const byte *inBlock, const byte *xorBlock, byte *outBlock) const
  {
      // Do the endian gyrations from the paper and align pointers
      typedef GetBlock<word64, LittleEndian, false> InBlock;
      InBlock iblk(inBlock); iblk(m_wspace[1])(m_wspace[0]);
  
      switch (m_rounds)
      {
      case 68:
          SIMON_Decrypt<word64, 68>(m_wspace+2, m_wspace+0, m_rkeys);
          break;
      case 69:
          SIMON_Decrypt<word64, 69>(m_wspace+2, m_wspace+0, m_rkeys);
          break;
      case 72:
          SIMON_Decrypt<word64, 72>(m_wspace+2, m_wspace+0, m_rkeys);
          break;
      default:
          CRYPTOPP_ASSERT(0);;
      }
  
      // Do the endian gyrations from the paper and align pointers
      typedef PutBlock<word64, LittleEndian, false> OutBlock;
      OutBlock oblk(xorBlock, outBlock); oblk(m_wspace[3])(m_wspace[2]);
  }
  
  #if defined(CRYPTOPP_SIMON64_ADVANCED_PROCESS_BLOCKS)
  size_t SIMON64::Enc::AdvancedProcessBlocks(const byte *inBlocks, const byte *xorBlocks,
          byte *outBlocks, size_t length, word32 flags) const
  {
  #if defined(CRYPTOPP_SSE41_AVAILABLE)
      if (HasSSE41())
          return SIMON64_Enc_AdvancedProcessBlocks_SSE41(m_rkeys, (size_t)m_rounds,
              inBlocks, xorBlocks, outBlocks, length, flags);
  #endif
  #if (CRYPTOPP_ARM_NEON_AVAILABLE)
      if (HasNEON())
          return SIMON64_Enc_AdvancedProcessBlocks_NEON(m_rkeys, (size_t)m_rounds,
              inBlocks, xorBlocks, outBlocks, length, flags);
  #endif
      return BlockTransformation::AdvancedProcessBlocks(inBlocks, xorBlocks, outBlocks, length, flags);
  }
  
  size_t SIMON64::Dec::AdvancedProcessBlocks(const byte *inBlocks, const byte *xorBlocks,
          byte *outBlocks, size_t length, word32 flags) const
  {
  #if defined(CRYPTOPP_SSE41_AVAILABLE)
      if (HasSSE41())
          return SIMON64_Dec_AdvancedProcessBlocks_SSE41(m_rkeys, (size_t)m_rounds,
              inBlocks, xorBlocks, outBlocks, length, flags);
  #endif
  #if (CRYPTOPP_ARM_NEON_AVAILABLE)
      if (HasNEON())
          return SIMON64_Dec_AdvancedProcessBlocks_NEON(m_rkeys, (size_t)m_rounds,
              inBlocks, xorBlocks, outBlocks, length, flags);
  #endif
      return BlockTransformation::AdvancedProcessBlocks(inBlocks, xorBlocks, outBlocks, length, flags);
  }
  #endif  // CRYPTOPP_SIMON64_ADVANCED_PROCESS_BLOCKS
  
  #if defined(CRYPTOPP_SIMON128_ADVANCED_PROCESS_BLOCKS)
  size_t SIMON128::Enc::AdvancedProcessBlocks(const byte *inBlocks, const byte *xorBlocks,
          byte *outBlocks, size_t length, word32 flags) const
  {
  #if defined(CRYPTOPP_SSSE3_AVAILABLE)
      if (HasSSSE3())
          return SIMON128_Enc_AdvancedProcessBlocks_SSSE3(m_rkeys, (size_t)m_rounds,
              inBlocks, xorBlocks, outBlocks, length, flags);
  #endif
  #if (CRYPTOPP_ARM_NEON_AVAILABLE)
      if (HasNEON())
          return SIMON128_Enc_AdvancedProcessBlocks_NEON(m_rkeys, (size_t)m_rounds,
              inBlocks, xorBlocks, outBlocks, length, flags);
  #endif
      return BlockTransformation::AdvancedProcessBlocks(inBlocks, xorBlocks, outBlocks, length, flags);
  }
  
  size_t SIMON128::Dec::AdvancedProcessBlocks(const byte *inBlocks, const byte *xorBlocks,
          byte *outBlocks, size_t length, word32 flags) const
  {
  #if defined(CRYPTOPP_SSSE3_AVAILABLE)
      if (HasSSSE3())
          return SIMON128_Dec_AdvancedProcessBlocks_SSSE3(m_rkeys, (size_t)m_rounds,
              inBlocks, xorBlocks, outBlocks, length, flags);
  #endif
  #if (CRYPTOPP_ARM_NEON_AVAILABLE)
      if (HasNEON())
          return SIMON128_Dec_AdvancedProcessBlocks_NEON(m_rkeys, (size_t)m_rounds,
              inBlocks, xorBlocks, outBlocks, length, flags);
  #endif
      return BlockTransformation::AdvancedProcessBlocks(inBlocks, xorBlocks, outBlocks, length, flags);
  }
  #endif  // CRYPTOPP_SIMON128_ADVANCED_PROCESS_BLOCKS
  
  NAMESPACE_END
  