/*
   * Copyright (C) 2013 Freie Universität Berlin, Computer Systems & Telematics
   *
   * This file is subject to the terms and conditions of the GNU Lesser
   * General Public License v2.1. See the file LICENSE in the top level
   * directory for more details.
   */
  
  
  /**
   * @ingroup     sys_crypto
   * @{
   *
   * @file
   * @brief       implementation of the twofish cipher-algorithm
   *
   * @author      Freie Universitaet Berlin, Computer Systems & Telematics
   * @author      Nicolai Schmittberger <nicolai.schmittberger@fu-berlin.de>
   * @author      Zakaria Kasmi <zkasmi@inf.fu-berlin.de>
   * @author      Matthew Skala <mskala@ansuz.sooke.bc.ca>
   *
   * @}
   */
  
  #include <stdio.h>
  #include <stdarg.h>
  #include <string.h>
  #include <stdlib.h>
  #include <stdint.h>
  #include "crypto/twofish.h"
  #include "crypto/ciphers.h"
  
  #define ENABLE_DEBUG    (0)
  #include "debug.h"
  
  //prototype
  static int twofish_setup_key(twofish_context_t *ctx, const uint8_t *key, uint8_t keylen);
  
  // twofish interface
  static const cipher_interface_t twofish_interface = {
      TWOFISH_BLOCK_SIZE,
      TWOFISH_KEY_SIZE,
      twofish_init,
      twofish_encrypt,
      twofish_decrypt
  };
  const cipher_id_t CIPHER_TWOFISH = &twofish_interface;
  
  /* These two tables are the q0 and q1 permutations, exactly as described in
   * the Twofish paper. */
  
  static const uint8_t q0[256] = {
      0xA9, 0x67, 0xB3, 0xE8, 0x04, 0xFD, 0xA3, 0x76, 0x9A, 0x92, 0x80, 0x78,
      0xE4, 0xDD, 0xD1, 0x38, 0x0D, 0xC6, 0x35, 0x98, 0x18, 0xF7, 0xEC, 0x6C,
      0x43, 0x75, 0x37, 0x26, 0xFA, 0x13, 0x94, 0x48, 0xF2, 0xD0, 0x8B, 0x30,
      0x84, 0x54, 0xDF, 0x23, 0x19, 0x5B, 0x3D, 0x59, 0xF3, 0xAE, 0xA2, 0x82,
      0x63, 0x01, 0x83, 0x2E, 0xD9, 0x51, 0x9B, 0x7C, 0xA6, 0xEB, 0xA5, 0xBE,
      0x16, 0x0C, 0xE3, 0x61, 0xC0, 0x8C, 0x3A, 0xF5, 0x73, 0x2C, 0x25, 0x0B,
      0xBB, 0x4E, 0x89, 0x6B, 0x53, 0x6A, 0xB4, 0xF1, 0xE1, 0xE6, 0xBD, 0x45,
      0xE2, 0xF4, 0xB6, 0x66, 0xCC, 0x95, 0x03, 0x56, 0xD4, 0x1C, 0x1E, 0xD7,
      0xFB, 0xC3, 0x8E, 0xB5, 0xE9, 0xCF, 0xBF, 0xBA, 0xEA, 0x77, 0x39, 0xAF,
      0x33, 0xC9, 0x62, 0x71, 0x81, 0x79, 0x09, 0xAD, 0x24, 0xCD, 0xF9, 0xD8,
      0xE5, 0xC5, 0xB9, 0x4D, 0x44, 0x08, 0x86, 0xE7, 0xA1, 0x1D, 0xAA, 0xED,
      0x06, 0x70, 0xB2, 0xD2, 0x41, 0x7B, 0xA0, 0x11, 0x31, 0xC2, 0x27, 0x90,
      0x20, 0xF6, 0x60, 0xFF, 0x96, 0x5C, 0xB1, 0xAB, 0x9E, 0x9C, 0x52, 0x1B,
      0x5F, 0x93, 0x0A, 0xEF, 0x91, 0x85, 0x49, 0xEE, 0x2D, 0x4F, 0x8F, 0x3B,
      0x47, 0x87, 0x6D, 0x46, 0xD6, 0x3E, 0x69, 0x64, 0x2A, 0xCE, 0xCB, 0x2F,
      0xFC, 0x97, 0x05, 0x7A, 0xAC, 0x7F, 0xD5, 0x1A, 0x4B, 0x0E, 0xA7, 0x5A,
      0x28, 0x14, 0x3F, 0x29, 0x88, 0x3C, 0x4C, 0x02, 0xB8, 0xDA, 0xB0, 0x17,
      0x55, 0x1F, 0x8A, 0x7D, 0x57, 0xC7, 0x8D, 0x74, 0xB7, 0xC4, 0x9F, 0x72,
      0x7E, 0x15, 0x22, 0x12, 0x58, 0x07, 0x99, 0x34, 0x6E, 0x50, 0xDE, 0x68,
      0x65, 0xBC, 0xDB, 0xF8, 0xC8, 0xA8, 0x2B, 0x40, 0xDC, 0xFE, 0x32, 0xA4,
      0xCA, 0x10, 0x21, 0xF0, 0xD3, 0x5D, 0x0F, 0x00, 0x6F, 0x9D, 0x36, 0x42,
      0x4A, 0x5E, 0xC1, 0xE0
  };
  
  static const uint8_t q1[256] = {
      0x75, 0xF3, 0xC6, 0xF4, 0xDB, 0x7B, 0xFB, 0xC8, 0x4A, 0xD3, 0xE6, 0x6B,
      0x45, 0x7D, 0xE8, 0x4B, 0xD6, 0x32, 0xD8, 0xFD, 0x37, 0x71, 0xF1, 0xE1,
      0x30, 0x0F, 0xF8, 0x1B, 0x87, 0xFA, 0x06, 0x3F, 0x5E, 0xBA, 0xAE, 0x5B,
      0x8A, 0x00, 0xBC, 0x9D, 0x6D, 0xC1, 0xB1, 0x0E, 0x80, 0x5D, 0xD2, 0xD5,
      0xA0, 0x84, 0x07, 0x14, 0xB5, 0x90, 0x2C, 0xA3, 0xB2, 0x73, 0x4C, 0x54,
      0x92, 0x74, 0x36, 0x51, 0x38, 0xB0, 0xBD, 0x5A, 0xFC, 0x60, 0x62, 0x96,
      0x6C, 0x42, 0xF7, 0x10, 0x7C, 0x28, 0x27, 0x8C, 0x13, 0x95, 0x9C, 0xC7,
      0x24, 0x46, 0x3B, 0x70, 0xCA, 0xE3, 0x85, 0xCB, 0x11, 0xD0, 0x93, 0xB8,
      0xA6, 0x83, 0x20, 0xFF, 0x9F, 0x77, 0xC3, 0xCC, 0x03, 0x6F, 0x08, 0xBF,
      0x40, 0xE7, 0x2B, 0xE2, 0x79, 0x0C, 0xAA, 0x82, 0x41, 0x3A, 0xEA, 0xB9,
      0xE4, 0x9A, 0xA4, 0x97, 0x7E, 0xDA, 0x7A, 0x17, 0x66, 0x94, 0xA1, 0x1D,
      0x3D, 0xF0, 0xDE, 0xB3, 0x0B, 0x72, 0xA7, 0x1C, 0xEF, 0xD1, 0x53, 0x3E,
      0x8F, 0x33, 0x26, 0x5F, 0xEC, 0x76, 0x2A, 0x49, 0x81, 0x88, 0xEE, 0x21,
      0xC4, 0x1A, 0xEB, 0xD9, 0xC5, 0x39, 0x99, 0xCD, 0xAD, 0x31, 0x8B, 0x01,
      0x18, 0x23, 0xDD, 0x1F, 0x4E, 0x2D, 0xF9, 0x48, 0x4F, 0xF2, 0x65, 0x8E,
      0x78, 0x5C, 0x58, 0x19, 0x8D, 0xE5, 0x98, 0x57, 0x67, 0x7F, 0x05, 0x64,
      0xAF, 0x63, 0xB6, 0xFE, 0xF5, 0xB7, 0x3C, 0xA5, 0xCE, 0xE9, 0x68, 0x44,
      0xE0, 0x4D, 0x43, 0x69, 0x29, 0x2E, 0xAC, 0x15, 0x59, 0xA8, 0x0A, 0x9E,
      0x6E, 0x47, 0xDF, 0x34, 0x35, 0x6A, 0xCF, 0xDC, 0x22, 0xC9, 0xC0, 0x9B,
      0x89, 0xD4, 0xED, 0xAB, 0x12, 0xA2, 0x0D, 0x52, 0xBB, 0x02, 0x2F, 0xA9,
      0xD7, 0x61, 0x1E, 0xB4, 0x50, 0x04, 0xF6, 0xC2, 0x16, 0x25, 0x86, 0x56,
      0x55, 0x09, 0xBE, 0x91
  };
  
  /*
   * These MDS tables are actually tables of MDS composed with q0 and q1,
   * because it is only ever used that way and we can save some time by
   * precomputing.  Of course the main saving comes from precomputing the
   * GF(2^8) multiplication involved in the MDS matrix multiply; by looking
   * things up in these tables we reduce the matrix multiply to four lookups
   * and three XORs.  Semi-formally, the definition of these tables is:
   * mds[0][i] = MDS (q1[i] 0 0 0)^T  mds[1][i] = MDS (0 q0[i] 0 0)^T
   * mds[2][i] = MDS (0 0 q1[i] 0)^T  mds[3][i] = MDS (0 0 0 q0[i])^T
   * where ^T means "transpose", the matrix multiply is performed in GF(2^8)
   * represented as GF(2)[x]/v(x) where v(x)=x^8+x^6+x^5+x^3+1 as described
   * by Schneier et al, and I'm casually glossing over the byte/word
   * conversion issues.
   */
  
  static const uint32_t mds[4][256] = {
      {
          0xBCBC3275, 0xECEC21F3, 0x202043C6, 0xB3B3C9F4, 0xDADA03DB, 0x02028B7B,
          0xE2E22BFB, 0x9E9EFAC8, 0xC9C9EC4A, 0xD4D409D3, 0x18186BE6, 0x1E1E9F6B,
          0x98980E45, 0xB2B2387D, 0xA6A6D2E8, 0x2626B74B, 0x3C3C57D6, 0x93938A32,
          0x8282EED8, 0x525298FD, 0x7B7BD437, 0xBBBB3771, 0x5B5B97F1, 0x474783E1,
          0x24243C30, 0x5151E20F, 0xBABAC6F8, 0x4A4AF31B, 0xBFBF4887, 0x0D0D70FA,
          0xB0B0B306, 0x7575DE3F, 0xD2D2FD5E, 0x7D7D20BA, 0x666631AE, 0x3A3AA35B,
          0x59591C8A, 0x00000000, 0xCDCD93BC, 0x1A1AE09D, 0xAEAE2C6D, 0x7F7FABC1,
          0x2B2BC7B1, 0xBEBEB90E, 0xE0E0A080, 0x8A8A105D, 0x3B3B52D2, 0x6464BAD5,
          0xD8D888A0, 0xE7E7A584, 0x5F5FE807, 0x1B1B1114, 0x2C2CC2B5, 0xFCFCB490,
          0x3131272C, 0x808065A3, 0x73732AB2, 0x0C0C8173, 0x79795F4C, 0x6B6B4154,
          0x4B4B0292, 0x53536974, 0x94948F36, 0x83831F51, 0x2A2A3638, 0xC4C49CB0,
          0x2222C8BD, 0xD5D5F85A, 0xBDBDC3FC, 0x48487860, 0xFFFFCE62, 0x4C4C0796,
          0x4141776C, 0xC7C7E642, 0xEBEB24F7, 0x1C1C1410, 0x5D5D637C, 0x36362228,
          0x6767C027, 0xE9E9AF8C, 0x4444F913, 0x1414EA95, 0xF5F5BB9C, 0xCFCF18C7,
          0x3F3F2D24, 0xC0C0E346, 0x7272DB3B, 0x54546C70, 0x29294CCA, 0xF0F035E3,
          0x0808FE85, 0xC6C617CB, 0xF3F34F11, 0x8C8CE4D0, 0xA4A45993, 0xCACA96B8,
          0x68683BA6, 0xB8B84D83, 0x38382820, 0xE5E52EFF, 0xADAD569F, 0x0B0B8477,
          0xC8C81DC3, 0x9999FFCC, 0x5858ED03, 0x19199A6F, 0x0E0E0A08, 0x95957EBF,
          0x70705040, 0xF7F730E7, 0x6E6ECF2B, 0x1F1F6EE2, 0xB5B53D79, 0x09090F0C,
          0x616134AA, 0x57571682, 0x9F9F0B41, 0x9D9D803A, 0x111164EA, 0x2525CDB9,
          0xAFAFDDE4, 0x4545089A, 0xDFDF8DA4, 0xA3A35C97, 0xEAEAD57E, 0x353558DA,
          0xEDEDD07A, 0x4343FC17, 0xF8F8CB66, 0xFBFBB194, 0x3737D3A1, 0xFAFA401D,
          0xC2C2683D, 0xB4B4CCF0, 0x32325DDE, 0x9C9C71B3, 0x5656E70B, 0xE3E3DA72,
          0x878760A7, 0x15151B1C, 0xF9F93AEF, 0x6363BFD1, 0x3434A953, 0x9A9A853E,
          0xB1B1428F, 0x7C7CD133, 0x88889B26, 0x3D3DA65F, 0xA1A1D7EC, 0xE4E4DF76,
          0x8181942A, 0x91910149, 0x0F0FFB81, 0xEEEEAA88, 0x161661EE, 0xD7D77321,
          0x9797F5C4, 0xA5A5A81A, 0xFEFE3FEB, 0x6D6DB5D9, 0x7878AEC5, 0xC5C56D39,
          0x1D1DE599, 0x7676A4CD, 0x3E3EDCAD, 0xCBCB6731, 0xB6B6478B, 0xEFEF5B01,
          0x12121E18, 0x6060C523, 0x6A6AB0DD, 0x4D4DF61F, 0xCECEE94E, 0xDEDE7C2D,
          0x55559DF9, 0x7E7E5A48, 0x2121B24F, 0x03037AF2, 0xA0A02665, 0x5E5E198E,
          0x5A5A6678, 0x65654B5C, 0x62624E58, 0xFDFD4519, 0x0606F48D, 0x404086E5,
          0xF2F2BE98, 0x3333AC57, 0x17179067, 0x05058E7F, 0xE8E85E05, 0x4F4F7D64,
          0x89896AAF, 0x10109563, 0x74742FB6, 0x0A0A75FE, 0x5C5C92F5, 0x9B9B74B7,
          0x2D2D333C, 0x3030D6A5, 0x2E2E49CE, 0x494989E9, 0x46467268, 0x77775544,
          0xA8A8D8E0, 0x9696044D, 0x2828BD43, 0xA9A92969, 0xD9D97929, 0x8686912E,
          0xD1D187AC, 0xF4F44A15, 0x8D8D1559, 0xD6D682A8, 0xB9B9BC0A, 0x42420D9E,
          0xF6F6C16E, 0x2F2FB847, 0xDDDD06DF, 0x23233934, 0xCCCC6235, 0xF1F1C46A,
          0xC1C112CF, 0x8585EBDC, 0x8F8F9E22, 0x7171A1C9, 0x9090F0C0, 0xAAAA539B,
          0x0101F189, 0x8B8BE1D4, 0x4E4E8CED, 0x8E8E6FAB, 0xABABA212, 0x6F6F3EA2,
          0xE6E6540D, 0xDBDBF252, 0x92927BBB, 0xB7B7B602, 0x6969CA2F, 0x3939D9A9,
          0xD3D30CD7, 0xA7A72361, 0xA2A2AD1E, 0xC3C399B4, 0x6C6C4450, 0x07070504,
          0x04047FF6, 0x272746C2, 0xACACA716, 0xD0D07625, 0x50501386, 0xDCDCF756,
          0x84841A55, 0xE1E15109, 0x7A7A25BE, 0x1313EF91
      },
  
      {
          0xA9D93939, 0x67901717, 0xB3719C9C, 0xE8D2A6A6, 0x04050707, 0xFD985252,
          0xA3658080, 0x76DFE4E4, 0x9A084545, 0x92024B4B, 0x80A0E0E0, 0x78665A5A,
          0xE4DDAFAF, 0xDDB06A6A, 0xD1BF6363, 0x38362A2A, 0x0D54E6E6, 0xC6432020,
          0x3562CCCC, 0x98BEF2F2, 0x181E1212, 0xF724EBEB, 0xECD7A1A1, 0x6C774141,
          0x43BD2828, 0x7532BCBC, 0x37D47B7B, 0x269B8888, 0xFA700D0D, 0x13F94444,
          0x94B1FBFB, 0x485A7E7E, 0xF27A0303, 0xD0E48C8C, 0x8B47B6B6, 0x303C2424,
          0x84A5E7E7, 0x54416B6B, 0xDF06DDDD, 0x23C56060, 0x1945FDFD, 0x5BA33A3A,
          0x3D68C2C2, 0x59158D8D, 0xF321ECEC, 0xAE316666, 0xA23E6F6F, 0x82165757,
          0x63951010, 0x015BEFEF, 0x834DB8B8, 0x2E918686, 0xD9B56D6D, 0x511F8383,
          0x9B53AAAA, 0x7C635D5D, 0xA63B6868, 0xEB3FFEFE, 0xA5D63030, 0xBE257A7A,
          0x16A7ACAC, 0x0C0F0909, 0xE335F0F0, 0x6123A7A7, 0xC0F09090, 0x8CAFE9E9,
          0x3A809D9D, 0xF5925C5C, 0x73810C0C, 0x2C273131, 0x2576D0D0, 0x0BE75656,
          0xBB7B9292, 0x4EE9CECE, 0x89F10101, 0x6B9F1E1E, 0x53A93434, 0x6AC4F1F1,
          0xB499C3C3, 0xF1975B5B, 0xE1834747, 0xE66B1818, 0xBDC82222, 0x450E9898,
          0xE26E1F1F, 0xF4C9B3B3, 0xB62F7474, 0x66CBF8F8, 0xCCFF9999, 0x95EA1414,
          0x03ED5858, 0x56F7DCDC, 0xD4E18B8B, 0x1C1B1515, 0x1EADA2A2, 0xD70CD3D3,
          0xFB2BE2E2, 0xC31DC8C8, 0x8E195E5E, 0xB5C22C2C, 0xE9894949, 0xCF12C1C1,
          0xBF7E9595, 0xBA207D7D, 0xEA641111, 0x77840B0B, 0x396DC5C5, 0xAF6A8989,
          0x33D17C7C, 0xC9A17171, 0x62CEFFFF, 0x7137BBBB, 0x81FB0F0F, 0x793DB5B5,
          0x0951E1E1, 0xADDC3E3E, 0x242D3F3F, 0xCDA47676, 0xF99D5555, 0xD8EE8282,
          0xE5864040, 0xC5AE7878, 0xB9CD2525, 0x4D049696, 0x44557777, 0x080A0E0E,
          0x86135050, 0xE730F7F7, 0xA1D33737, 0x1D40FAFA, 0xAA346161, 0xED8C4E4E,
          0x06B3B0B0, 0x706C5454, 0xB22A7373, 0xD2523B3B, 0x410B9F9F, 0x7B8B0202,
          0xA088D8D8, 0x114FF3F3, 0x3167CBCB, 0xC2462727, 0x27C06767, 0x90B4FCFC,
          0x20283838, 0xF67F0404, 0x60784848, 0xFF2EE5E5, 0x96074C4C, 0x5C4B6565,
          0xB1C72B2B, 0xAB6F8E8E, 0x9E0D4242, 0x9CBBF5F5, 0x52F2DBDB, 0x1BF34A4A,
          0x5FA63D3D, 0x9359A4A4, 0x0ABCB9B9, 0xEF3AF9F9, 0x91EF1313, 0x85FE0808,
          0x49019191, 0xEE611616, 0x2D7CDEDE, 0x4FB22121, 0x8F42B1B1, 0x3BDB7272,
          0x47B82F2F, 0x8748BFBF, 0x6D2CAEAE, 0x46E3C0C0, 0xD6573C3C, 0x3E859A9A,
          0x6929A9A9, 0x647D4F4F, 0x2A948181, 0xCE492E2E, 0xCB17C6C6, 0x2FCA6969,
          0xFCC3BDBD, 0x975CA3A3, 0x055EE8E8, 0x7AD0EDED, 0xAC87D1D1, 0x7F8E0505,
          0xD5BA6464, 0x1AA8A5A5, 0x4BB72626, 0x0EB9BEBE, 0xA7608787, 0x5AF8D5D5,
          0x28223636, 0x14111B1B, 0x3FDE7575, 0x2979D9D9, 0x88AAEEEE, 0x3C332D2D,
          0x4C5F7979, 0x02B6B7B7, 0xB896CACA, 0xDA583535, 0xB09CC4C4, 0x17FC4343,
          0x551A8484, 0x1FF64D4D, 0x8A1C5959, 0x7D38B2B2, 0x57AC3333, 0xC718CFCF,
          0x8DF40606, 0x74695353, 0xB7749B9B, 0xC4F59797, 0x9F56ADAD, 0x72DAE3E3,
          0x7ED5EAEA, 0x154AF4F4, 0x229E8F8F, 0x12A2ABAB, 0x584E6262, 0x07E85F5F,
          0x99E51D1D, 0x34392323, 0x6EC1F6F6, 0x50446C6C, 0xDE5D3232, 0x68724646,
          0x6526A0A0, 0xBC93CDCD, 0xDB03DADA, 0xF8C6BABA, 0xC8FA9E9E, 0xA882D6D6,
          0x2BCF6E6E, 0x40507070, 0xDCEB8585, 0xFE750A0A, 0x328A9393, 0xA48DDFDF,
          0xCA4C2929, 0x10141C1C, 0x2173D7D7, 0xF0CCB4B4, 0xD309D4D4, 0x5D108A8A,
          0x0FE25151, 0x00000000, 0x6F9A1919, 0x9DE01A1A, 0x368F9494, 0x42E6C7C7,
          0x4AECC9C9, 0x5EFDD2D2, 0xC1AB7F7F, 0xE0D8A8A8
      },
  
      {
          0xBC75BC32, 0xECF3EC21, 0x20C62043, 0xB3F4B3C9, 0xDADBDA03, 0x027B028B,
          0xE2FBE22B, 0x9EC89EFA, 0xC94AC9EC, 0xD4D3D409, 0x18E6186B, 0x1E6B1E9F,
          0x9845980E, 0xB27DB238, 0xA6E8A6D2, 0x264B26B7, 0x3CD63C57, 0x9332938A,
          0x82D882EE, 0x52FD5298, 0x7B377BD4, 0xBB71BB37, 0x5BF15B97, 0x47E14783,
          0x2430243C, 0x510F51E2, 0xBAF8BAC6, 0x4A1B4AF3, 0xBF87BF48, 0x0DFA0D70,
          0xB006B0B3, 0x753F75DE, 0xD25ED2FD, 0x7DBA7D20, 0x66AE6631, 0x3A5B3AA3,
          0x598A591C, 0x00000000, 0xCDBCCD93, 0x1A9D1AE0, 0xAE6DAE2C, 0x7FC17FAB,
          0x2BB12BC7, 0xBE0EBEB9, 0xE080E0A0, 0x8A5D8A10, 0x3BD23B52, 0x64D564BA,
          0xD8A0D888, 0xE784E7A5, 0x5F075FE8, 0x1B141B11, 0x2CB52CC2, 0xFC90FCB4,
          0x312C3127, 0x80A38065, 0x73B2732A, 0x0C730C81, 0x794C795F, 0x6B546B41,
          0x4B924B02, 0x53745369, 0x9436948F, 0x8351831F, 0x2A382A36, 0xC4B0C49C,
          0x22BD22C8, 0xD55AD5F8, 0xBDFCBDC3, 0x48604878, 0xFF62FFCE, 0x4C964C07,
          0x416C4177, 0xC742C7E6, 0xEBF7EB24, 0x1C101C14, 0x5D7C5D63, 0x36283622,
          0x672767C0, 0xE98CE9AF, 0x441344F9, 0x149514EA, 0xF59CF5BB, 0xCFC7CF18,
          0x3F243F2D, 0xC046C0E3, 0x723B72DB, 0x5470546C, 0x29CA294C, 0xF0E3F035,
          0x088508FE, 0xC6CBC617, 0xF311F34F, 0x8CD08CE4, 0xA493A459, 0xCAB8CA96,
          0x68A6683B, 0xB883B84D, 0x38203828, 0xE5FFE52E, 0xAD9FAD56, 0x0B770B84,
          0xC8C3C81D, 0x99CC99FF, 0x580358ED, 0x196F199A, 0x0E080E0A, 0x95BF957E,
          0x70407050, 0xF7E7F730, 0x6E2B6ECF, 0x1FE21F6E, 0xB579B53D, 0x090C090F,
          0x61AA6134, 0x57825716, 0x9F419F0B, 0x9D3A9D80, 0x11EA1164, 0x25B925CD,
          0xAFE4AFDD, 0x459A4508, 0xDFA4DF8D, 0xA397A35C, 0xEA7EEAD5, 0x35DA3558,
          0xED7AEDD0, 0x431743FC, 0xF866F8CB, 0xFB94FBB1, 0x37A137D3, 0xFA1DFA40,
          0xC23DC268, 0xB4F0B4CC, 0x32DE325D, 0x9CB39C71, 0x560B56E7, 0xE372E3DA,
          0x87A78760, 0x151C151B, 0xF9EFF93A, 0x63D163BF, 0x345334A9, 0x9A3E9A85,
          0xB18FB142, 0x7C337CD1, 0x8826889B, 0x3D5F3DA6, 0xA1ECA1D7, 0xE476E4DF,
          0x812A8194, 0x91499101, 0x0F810FFB, 0xEE88EEAA, 0x16EE1661, 0xD721D773,
          0x97C497F5, 0xA51AA5A8, 0xFEEBFE3F, 0x6DD96DB5, 0x78C578AE, 0xC539C56D,
          0x1D991DE5, 0x76CD76A4, 0x3EAD3EDC, 0xCB31CB67, 0xB68BB647, 0xEF01EF5B,
          0x1218121E, 0x602360C5, 0x6ADD6AB0, 0x4D1F4DF6, 0xCE4ECEE9, 0xDE2DDE7C,
          0x55F9559D, 0x7E487E5A, 0x214F21B2, 0x03F2037A, 0xA065A026, 0x5E8E5E19,
          0x5A785A66, 0x655C654B, 0x6258624E, 0xFD19FD45, 0x068D06F4, 0x40E54086,
          0xF298F2BE, 0x335733AC, 0x17671790, 0x057F058E, 0xE805E85E, 0x4F644F7D,
          0x89AF896A, 0x10631095, 0x74B6742F, 0x0AFE0A75, 0x5CF55C92, 0x9BB79B74,
          0x2D3C2D33, 0x30A530D6, 0x2ECE2E49, 0x49E94989, 0x46684672, 0x77447755,
          0xA8E0A8D8, 0x964D9604, 0x284328BD, 0xA969A929, 0xD929D979, 0x862E8691,
          0xD1ACD187, 0xF415F44A, 0x8D598D15, 0xD6A8D682, 0xB90AB9BC, 0x429E420D,
          0xF66EF6C1, 0x2F472FB8, 0xDDDFDD06, 0x23342339, 0xCC35CC62, 0xF16AF1C4,
          0xC1CFC112, 0x85DC85EB, 0x8F228F9E, 0x71C971A1, 0x90C090F0, 0xAA9BAA53,
          0x018901F1, 0x8BD48BE1, 0x4EED4E8C, 0x8EAB8E6F, 0xAB12ABA2, 0x6FA26F3E,
          0xE60DE654, 0xDB52DBF2, 0x92BB927B, 0xB702B7B6, 0x692F69CA, 0x39A939D9,
          0xD3D7D30C, 0xA761A723, 0xA21EA2AD, 0xC3B4C399, 0x6C506C44, 0x07040705,
          0x04F6047F, 0x27C22746, 0xAC16ACA7, 0xD025D076, 0x50865013, 0xDC56DCF7,
          0x8455841A, 0xE109E151, 0x7ABE7A25, 0x139113EF
      },
  
      {
          0xD939A9D9, 0x90176790, 0x719CB371, 0xD2A6E8D2, 0x05070405, 0x9852FD98,
          0x6580A365, 0xDFE476DF, 0x08459A08, 0x024B9202, 0xA0E080A0, 0x665A7866,
          0xDDAFE4DD, 0xB06ADDB0, 0xBF63D1BF, 0x362A3836, 0x54E60D54, 0x4320C643,
          0x62CC3562, 0xBEF298BE, 0x1E12181E, 0x24EBF724, 0xD7A1ECD7, 0x77416C77,
          0xBD2843BD, 0x32BC7532, 0xD47B37D4, 0x9B88269B, 0x700DFA70, 0xF94413F9,
          0xB1FB94B1, 0x5A7E485A, 0x7A03F27A, 0xE48CD0E4, 0x47B68B47, 0x3C24303C,
          0xA5E784A5, 0x416B5441, 0x06DDDF06, 0xC56023C5, 0x45FD1945, 0xA33A5BA3,
          0x68C23D68, 0x158D5915, 0x21ECF321, 0x3166AE31, 0x3E6FA23E, 0x16578216,
          0x95106395, 0x5BEF015B, 0x4DB8834D, 0x91862E91, 0xB56DD9B5, 0x1F83511F,
          0x53AA9B53, 0x635D7C63, 0x3B68A63B, 0x3FFEEB3F, 0xD630A5D6, 0x257ABE25,
          0xA7AC16A7, 0x0F090C0F, 0x35F0E335, 0x23A76123, 0xF090C0F0, 0xAFE98CAF,
          0x809D3A80, 0x925CF592, 0x810C7381, 0x27312C27, 0x76D02576, 0xE7560BE7,
          0x7B92BB7B, 0xE9CE4EE9, 0xF10189F1, 0x9F1E6B9F, 0xA93453A9, 0xC4F16AC4,
          0x99C3B499, 0x975BF197, 0x8347E183, 0x6B18E66B, 0xC822BDC8, 0x0E98450E,
          0x6E1FE26E, 0xC9B3F4C9, 0x2F74B62F, 0xCBF866CB, 0xFF99CCFF, 0xEA1495EA,
          0xED5803ED, 0xF7DC56F7, 0xE18BD4E1, 0x1B151C1B, 0xADA21EAD, 0x0CD3D70C,
          0x2BE2FB2B, 0x1DC8C31D, 0x195E8E19, 0xC22CB5C2, 0x8949E989, 0x12C1CF12,
          0x7E95BF7E, 0x207DBA20, 0x6411EA64, 0x840B7784, 0x6DC5396D, 0x6A89AF6A,
          0xD17C33D1, 0xA171C9A1, 0xCEFF62CE, 0x37BB7137, 0xFB0F81FB, 0x3DB5793D,
          0x51E10951, 0xDC3EADDC, 0x2D3F242D, 0xA476CDA4, 0x9D55F99D, 0xEE82D8EE,
          0x8640E586, 0xAE78C5AE, 0xCD25B9CD, 0x04964D04, 0x55774455, 0x0A0E080A,
          0x13508613, 0x30F7E730, 0xD337A1D3, 0x40FA1D40, 0x3461AA34, 0x8C4EED8C,
          0xB3B006B3, 0x6C54706C, 0x2A73B22A, 0x523BD252, 0x0B9F410B, 0x8B027B8B,
          0x88D8A088, 0x4FF3114F, 0x67CB3167, 0x4627C246, 0xC06727C0, 0xB4FC90B4,
          0x28382028, 0x7F04F67F, 0x78486078, 0x2EE5FF2E, 0x074C9607, 0x4B655C4B,
          0xC72BB1C7, 0x6F8EAB6F, 0x0D429E0D, 0xBBF59CBB, 0xF2DB52F2, 0xF34A1BF3,
          0xA63D5FA6, 0x59A49359, 0xBCB90ABC, 0x3AF9EF3A, 0xEF1391EF, 0xFE0885FE,
          0x01914901, 0x6116EE61, 0x7CDE2D7C, 0xB2214FB2, 0x42B18F42, 0xDB723BDB,
          0xB82F47B8, 0x48BF8748, 0x2CAE6D2C, 0xE3C046E3, 0x573CD657, 0x859A3E85,
          0x29A96929, 0x7D4F647D, 0x94812A94, 0x492ECE49, 0x17C6CB17, 0xCA692FCA,
          0xC3BDFCC3, 0x5CA3975C, 0x5EE8055E, 0xD0ED7AD0, 0x87D1AC87, 0x8E057F8E,
          0xBA64D5BA, 0xA8A51AA8, 0xB7264BB7, 0xB9BE0EB9, 0x6087A760, 0xF8D55AF8,
          0x22362822, 0x111B1411, 0xDE753FDE, 0x79D92979, 0xAAEE88AA, 0x332D3C33,
          0x5F794C5F, 0xB6B702B6, 0x96CAB896, 0x5835DA58, 0x9CC4B09C, 0xFC4317FC,
          0x1A84551A, 0xF64D1FF6, 0x1C598A1C, 0x38B27D38, 0xAC3357AC, 0x18CFC718,
          0xF4068DF4, 0x69537469, 0x749BB774, 0xF597C4F5, 0x56AD9F56, 0xDAE372DA,
          0xD5EA7ED5, 0x4AF4154A, 0x9E8F229E, 0xA2AB12A2, 0x4E62584E, 0xE85F07E8,
          0xE51D99E5, 0x39233439, 0xC1F66EC1, 0x446C5044, 0x5D32DE5D, 0x72466872,
          0x26A06526, 0x93CDBC93, 0x03DADB03, 0xC6BAF8C6, 0xFA9EC8FA, 0x82D6A882,
          0xCF6E2BCF, 0x50704050, 0xEB85DCEB, 0x750AFE75, 0x8A93328A, 0x8DDFA48D,
          0x4C29CA4C, 0x141C1014, 0x73D72173, 0xCCB4F0CC, 0x09D4D309, 0x108A5D10,
          0xE2510FE2, 0x00000000, 0x9A196F9A, 0xE01A9DE0, 0x8F94368F, 0xE6C742E6,
          0xECC94AEC, 0xFDD25EFD, 0xAB7FC1AB, 0xD8A8E0D8
      }
  };
  
  /* The exp_to_poly and poly_to_exp tables are used to perform efficient
   * operations in GF(2^8) represented as GF(2)[x]/w(x) where
   * w(x)=x^8+x^6+x^3+x^2+1.  We care about doing that because it's part of the
   * definition of the RS matrix in the key schedule.  Elements of that field
   * are polynomials of degree not greater than 7 and all coefficients 0 or 1,
   * which can be represented naturally by bytes (just substitute x=2). In that
   * form, GF(2^8) addition is the same as bitwise XOR, but GF(2^8)
   * multiplication is inefficient without hardware support.  To multiply
   * faster, I make use of the fact x is a generator for the nonzero elements,
   * so that every element p of GF(2)[x]/w(x) is either 0 or equal to (x)^n for
   * some n in 0..254.  Note that that caret is exponentiation in GF(2^8),
   * *not* polynomial notation.  So if I want to compute pq where p and q are
   * in GF(2^8), I can just say:
   *    1. if p=0 or q=0 then pq=0
   *    2. otherwise, find m and n such that p=x^m and q=x^n
   *    3. pq=(x^m)(x^n)=x^(m+n), so add m and n and find pq
   * The translations in steps 2 and 3 are looked up in the tables
   * poly_to_exp (for step 2) and exp_to_poly (for step 3).  To see this
   * in action, look at the CALC_S macro.  As additional wrinkles, note that
   * one of my operands is always a constant, so the poly_to_exp lookup on it
   * is done in advance; I included the original values in the comments so
   * readers can have some chance of recognizing that this *is* the RS matrix
   * from the Twofish paper.  I've only included the table entries I actually
   * need; I never do a lookup on a variable input of zero and the biggest
   * exponents I'll ever see are 254 (variable) and 237 (constant), so they'll
   * never sum to more than 491.  I'm repeating part of the exp_to_poly table
   * so that I don't have to do mod-255 reduction in the exponent arithmetic.
   * Since I know my constant operands are never zero, I only have to worry
   * about zero values in the variable operand, and I do it with a simple
   * conditional branch.  I know conditionals are expensive, but I couldn't
   * see a non-horrible way of avoiding them, and I did manage to group the
   * statements so that each if covers four group multiplications.
   */
  
  static const uint8_t poly_to_exp[255] = {
      0x00, 0x01, 0x17, 0x02, 0x2E, 0x18, 0x53, 0x03, 0x6A, 0x2F, 0x93, 0x19,
      0x34, 0x54, 0x45, 0x04, 0x5C, 0x6B, 0xB6, 0x30, 0xA6, 0x94, 0x4B, 0x1A,
      0x8C, 0x35, 0x81, 0x55, 0xAA, 0x46, 0x0D, 0x05, 0x24, 0x5D, 0x87, 0x6C,
      0x9B, 0xB7, 0xC1, 0x31, 0x2B, 0xA7, 0xA3, 0x95, 0x98, 0x4C, 0xCA, 0x1B,
      0xE6, 0x8D, 0x73, 0x36, 0xCD, 0x82, 0x12, 0x56, 0x62, 0xAB, 0xF0, 0x47,
      0x4F, 0x0E, 0xBD, 0x06, 0xD4, 0x25, 0xD2, 0x5E, 0x27, 0x88, 0x66, 0x6D,
      0xD6, 0x9C, 0x79, 0xB8, 0x08, 0xC2, 0xDF, 0x32, 0x68, 0x2C, 0xFD, 0xA8,
      0x8A, 0xA4, 0x5A, 0x96, 0x29, 0x99, 0x22, 0x4D, 0x60, 0xCB, 0xE4, 0x1C,
      0x7B, 0xE7, 0x3B, 0x8E, 0x9E, 0x74, 0xF4, 0x37, 0xD8, 0xCE, 0xF9, 0x83,
      0x6F, 0x13, 0xB2, 0x57, 0xE1, 0x63, 0xDC, 0xAC, 0xC4, 0xF1, 0xAF, 0x48,
      0x0A, 0x50, 0x42, 0x0F, 0xBA, 0xBE, 0xC7, 0x07, 0xDE, 0xD5, 0x78, 0x26,
      0x65, 0xD3, 0xD1, 0x5F, 0xE3, 0x28, 0x21, 0x89, 0x59, 0x67, 0xFC, 0x6E,
      0xB1, 0xD7, 0xF8, 0x9D, 0xF3, 0x7A, 0x3A, 0xB9, 0xC6, 0x09, 0x41, 0xC3,
      0xAE, 0xE0, 0xDB, 0x33, 0x44, 0x69, 0x92, 0x2D, 0x52, 0xFE, 0x16, 0xA9,
      0x0C, 0x8B, 0x80, 0xA5, 0x4A, 0x5B, 0xB5, 0x97, 0xC9, 0x2A, 0xA2, 0x9A,
      0xC0, 0x23, 0x86, 0x4E, 0xBC, 0x61, 0xEF, 0xCC, 0x11, 0xE5, 0x72, 0x1D,
      0x3D, 0x7C, 0xEB, 0xE8, 0xE9, 0x3C, 0xEA, 0x8F, 0x7D, 0x9F, 0xEC, 0x75,
      0x1E, 0xF5, 0x3E, 0x38, 0xF6, 0xD9, 0x3F, 0xCF, 0x76, 0xFA, 0x1F, 0x84,
      0xA0, 0x70, 0xED, 0x14, 0x90, 0xB3, 0x7E, 0x58, 0xFB, 0xE2, 0x20, 0x64,
      0xD0, 0xDD, 0x77, 0xAD, 0xDA, 0xC5, 0x40, 0xF2, 0x39, 0xB0, 0xF7, 0x49,
      0xB4, 0x0B, 0x7F, 0x51, 0x15, 0x43, 0x91, 0x10, 0x71, 0xBB, 0xEE, 0xBF,
      0x85, 0xC8, 0xA1
  };
  
  static const uint8_t exp_to_poly[492] = {
      0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x4D, 0x9A, 0x79, 0xF2,
      0xA9, 0x1F, 0x3E, 0x7C, 0xF8, 0xBD, 0x37, 0x6E, 0xDC, 0xF5, 0xA7, 0x03,
      0x06, 0x0C, 0x18, 0x30, 0x60, 0xC0, 0xCD, 0xD7, 0xE3, 0x8B, 0x5B, 0xB6,
      0x21, 0x42, 0x84, 0x45, 0x8A, 0x59, 0xB2, 0x29, 0x52, 0xA4, 0x05, 0x0A,
      0x14, 0x28, 0x50, 0xA0, 0x0D, 0x1A, 0x34, 0x68, 0xD0, 0xED, 0x97, 0x63,
      0xC6, 0xC1, 0xCF, 0xD3, 0xEB, 0x9B, 0x7B, 0xF6, 0xA1, 0x0F, 0x1E, 0x3C,
      0x78, 0xF0, 0xAD, 0x17, 0x2E, 0x5C, 0xB8, 0x3D, 0x7A, 0xF4, 0xA5, 0x07,
      0x0E, 0x1C, 0x38, 0x70, 0xE0, 0x8D, 0x57, 0xAE, 0x11, 0x22, 0x44, 0x88,
      0x5D, 0xBA, 0x39, 0x72, 0xE4, 0x85, 0x47, 0x8E, 0x51, 0xA2, 0x09, 0x12,
      0x24, 0x48, 0x90, 0x6D, 0xDA, 0xF9, 0xBF, 0x33, 0x66, 0xCC, 0xD5, 0xE7,
      0x83, 0x4B, 0x96, 0x61, 0xC2, 0xC9, 0xDF, 0xF3, 0xAB, 0x1B, 0x36, 0x6C,
      0xD8, 0xFD, 0xB7, 0x23, 0x46, 0x8C, 0x55, 0xAA, 0x19, 0x32, 0x64, 0xC8,
      0xDD, 0xF7, 0xA3, 0x0B, 0x16, 0x2C, 0x58, 0xB0, 0x2D, 0x5A, 0xB4, 0x25,
      0x4A, 0x94, 0x65, 0xCA, 0xD9, 0xFF, 0xB3, 0x2B, 0x56, 0xAC, 0x15, 0x2A,
      0x54, 0xA8, 0x1D, 0x3A, 0x74, 0xE8, 0x9D, 0x77, 0xEE, 0x91, 0x6F, 0xDE,
      0xF1, 0xAF, 0x13, 0x26, 0x4C, 0x98, 0x7D, 0xFA, 0xB9, 0x3F, 0x7E, 0xFC,
      0xB5, 0x27, 0x4E, 0x9C, 0x75, 0xEA, 0x99, 0x7F, 0xFE, 0xB1, 0x2F, 0x5E,
      0xBC, 0x35, 0x6A, 0xD4, 0xE5, 0x87, 0x43, 0x86, 0x41, 0x82, 0x49, 0x92,
      0x69, 0xD2, 0xE9, 0x9F, 0x73, 0xE6, 0x81, 0x4F, 0x9E, 0x71, 0xE2, 0x89,
      0x5F, 0xBE, 0x31, 0x62, 0xC4, 0xC5, 0xC7, 0xC3, 0xCB, 0xDB, 0xFB, 0xBB,
      0x3B, 0x76, 0xEC, 0x95, 0x67, 0xCE, 0xD1, 0xEF, 0x93, 0x6B, 0xD6, 0xE1,
      0x8F, 0x53, 0xA6, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x4D,
      0x9A, 0x79, 0xF2, 0xA9, 0x1F, 0x3E, 0x7C, 0xF8, 0xBD, 0x37, 0x6E, 0xDC,
      0xF5, 0xA7, 0x03, 0x06, 0x0C, 0x18, 0x30, 0x60, 0xC0, 0xCD, 0xD7, 0xE3,
      0x8B, 0x5B, 0xB6, 0x21, 0x42, 0x84, 0x45, 0x8A, 0x59, 0xB2, 0x29, 0x52,
      0xA4, 0x05, 0x0A, 0x14, 0x28, 0x50, 0xA0, 0x0D, 0x1A, 0x34, 0x68, 0xD0,
      0xED, 0x97, 0x63, 0xC6, 0xC1, 0xCF, 0xD3, 0xEB, 0x9B, 0x7B, 0xF6, 0xA1,
      0x0F, 0x1E, 0x3C, 0x78, 0xF0, 0xAD, 0x17, 0x2E, 0x5C, 0xB8, 0x3D, 0x7A,
      0xF4, 0xA5, 0x07, 0x0E, 0x1C, 0x38, 0x70, 0xE0, 0x8D, 0x57, 0xAE, 0x11,
      0x22, 0x44, 0x88, 0x5D, 0xBA, 0x39, 0x72, 0xE4, 0x85, 0x47, 0x8E, 0x51,
      0xA2, 0x09, 0x12, 0x24, 0x48, 0x90, 0x6D, 0xDA, 0xF9, 0xBF, 0x33, 0x66,
      0xCC, 0xD5, 0xE7, 0x83, 0x4B, 0x96, 0x61, 0xC2, 0xC9, 0xDF, 0xF3, 0xAB,
      0x1B, 0x36, 0x6C, 0xD8, 0xFD, 0xB7, 0x23, 0x46, 0x8C, 0x55, 0xAA, 0x19,
      0x32, 0x64, 0xC8, 0xDD, 0xF7, 0xA3, 0x0B, 0x16, 0x2C, 0x58, 0xB0, 0x2D,
      0x5A, 0xB4, 0x25, 0x4A, 0x94, 0x65, 0xCA, 0xD9, 0xFF, 0xB3, 0x2B, 0x56,
      0xAC, 0x15, 0x2A, 0x54, 0xA8, 0x1D, 0x3A, 0x74, 0xE8, 0x9D, 0x77, 0xEE,
      0x91, 0x6F, 0xDE, 0xF1, 0xAF, 0x13, 0x26, 0x4C, 0x98, 0x7D, 0xFA, 0xB9,
      0x3F, 0x7E, 0xFC, 0xB5, 0x27, 0x4E, 0x9C, 0x75, 0xEA, 0x99, 0x7F, 0xFE,
      0xB1, 0x2F, 0x5E, 0xBC, 0x35, 0x6A, 0xD4, 0xE5, 0x87, 0x43, 0x86, 0x41,
      0x82, 0x49, 0x92, 0x69, 0xD2, 0xE9, 0x9F, 0x73, 0xE6, 0x81, 0x4F, 0x9E,
      0x71, 0xE2, 0x89, 0x5F, 0xBE, 0x31, 0x62, 0xC4, 0xC5, 0xC7, 0xC3, 0xCB
  };
  
  
  /* The table constants are indices of
   * S-box entries, preprocessed through q0 and q1. */
  static uint8_t calc_sb_tbl[512] = {
      0xA9, 0x75, 0x67, 0xF3, 0xB3, 0xC6, 0xE8, 0xF4,
      0x04, 0xDB, 0xFD, 0x7B, 0xA3, 0xFB, 0x76, 0xC8,
      0x9A, 0x4A, 0x92, 0xD3, 0x80, 0xE6, 0x78, 0x6B,
      0xE4, 0x45, 0xDD, 0x7D, 0xD1, 0xE8, 0x38, 0x4B,
      0x0D, 0xD6, 0xC6, 0x32, 0x35, 0xD8, 0x98, 0xFD,
      0x18, 0x37, 0xF7, 0x71, 0xEC, 0xF1, 0x6C, 0xE1,
      0x43, 0x30, 0x75, 0x0F, 0x37, 0xF8, 0x26, 0x1B,
      0xFA, 0x87, 0x13, 0xFA, 0x94, 0x06, 0x48, 0x3F,
      0xF2, 0x5E, 0xD0, 0xBA, 0x8B, 0xAE, 0x30, 0x5B,
      0x84, 0x8A, 0x54, 0x00, 0xDF, 0xBC, 0x23, 0x9D,
      0x19, 0x6D, 0x5B, 0xC1, 0x3D, 0xB1, 0x59, 0x0E,
      0xF3, 0x80, 0xAE, 0x5D, 0xA2, 0xD2, 0x82, 0xD5,
      0x63, 0xA0, 0x01, 0x84, 0x83, 0x07, 0x2E, 0x14,
      0xD9, 0xB5, 0x51, 0x90, 0x9B, 0x2C, 0x7C, 0xA3,
      0xA6, 0xB2, 0xEB, 0x73, 0xA5, 0x4C, 0xBE, 0x54,
      0x16, 0x92, 0x0C, 0x74, 0xE3, 0x36, 0x61, 0x51,
      0xC0, 0x38, 0x8C, 0xB0, 0x3A, 0xBD, 0xF5, 0x5A,
      0x73, 0xFC, 0x2C, 0x60, 0x25, 0x62, 0x0B, 0x96,
      0xBB, 0x6C, 0x4E, 0x42, 0x89, 0xF7, 0x6B, 0x10,
      0x53, 0x7C, 0x6A, 0x28, 0xB4, 0x27, 0xF1, 0x8C,
      0xE1, 0x13, 0xE6, 0x95, 0xBD, 0x9C, 0x45, 0xC7,
      0xE2, 0x24, 0xF4, 0x46, 0xB6, 0x3B, 0x66, 0x70,
      0xCC, 0xCA, 0x95, 0xE3, 0x03, 0x85, 0x56, 0xCB,
      0xD4, 0x11, 0x1C, 0xD0, 0x1E, 0x93, 0xD7, 0xB8,
      0xFB, 0xA6, 0xC3, 0x83, 0x8E, 0x20, 0xB5, 0xFF,
      0xE9, 0x9F, 0xCF, 0x77, 0xBF, 0xC3, 0xBA, 0xCC,
      0xEA, 0x03, 0x77, 0x6F, 0x39, 0x08, 0xAF, 0xBF,
      0x33, 0x40, 0xC9, 0xE7, 0x62, 0x2B, 0x71, 0xE2,
      0x81, 0x79, 0x79, 0x0C, 0x09, 0xAA, 0xAD, 0x82,
      0x24, 0x41, 0xCD, 0x3A, 0xF9, 0xEA, 0xD8, 0xB9,
      0xE5, 0xE4, 0xC5, 0x9A, 0xB9, 0xA4, 0x4D, 0x97,
      0x44, 0x7E, 0x08, 0xDA, 0x86, 0x7A, 0xE7, 0x17,
      0xA1, 0x66, 0x1D, 0x94, 0xAA, 0xA1, 0xED, 0x1D,
      0x06, 0x3D, 0x70, 0xF0, 0xB2, 0xDE, 0xD2, 0xB3,
      0x41, 0x0B, 0x7B, 0x72, 0xA0, 0xA7, 0x11, 0x1C,
      0x31, 0xEF, 0xC2, 0xD1, 0x27, 0x53, 0x90, 0x3E,
      0x20, 0x8F, 0xF6, 0x33, 0x60, 0x26, 0xFF, 0x5F,
      0x96, 0xEC, 0x5C, 0x76, 0xB1, 0x2A, 0xAB, 0x49,
      0x9E, 0x81, 0x9C, 0x88, 0x52, 0xEE, 0x1B, 0x21,
      0x5F, 0xC4, 0x93, 0x1A, 0x0A, 0xEB, 0xEF, 0xD9,
      0x91, 0xC5, 0x85, 0x39, 0x49, 0x99, 0xEE, 0xCD,
      0x2D, 0xAD, 0x4F, 0x31, 0x8F, 0x8B, 0x3B, 0x01,
      0x47, 0x18, 0x87, 0x23, 0x6D, 0xDD, 0x46, 0x1F,
      0xD6, 0x4E, 0x3E, 0x2D, 0x69, 0xF9, 0x64, 0x48,
      0x2A, 0x4F, 0xCE, 0xF2, 0xCB, 0x65, 0x2F, 0x8E,
      0xFC, 0x78, 0x97, 0x5C, 0x05, 0x58, 0x7A, 0x19,
      0xAC, 0x8D, 0x7F, 0xE5, 0xD5, 0x98, 0x1A, 0x57,
      0x4B, 0x67, 0x0E, 0x7F, 0xA7, 0x05, 0x5A, 0x64,
      0x28, 0xAF, 0x14, 0x63, 0x3F, 0xB6, 0x29, 0xFE,
      0x88, 0xF5, 0x3C, 0xB7, 0x4C, 0x3C, 0x02, 0xA5,
      0xB8, 0xCE, 0xDA, 0xE9, 0xB0, 0x68, 0x17, 0x44,
      0x55, 0xE0, 0x1F, 0x4D, 0x8A, 0x43, 0x7D, 0x69,
      0x57, 0x29, 0xC7, 0x2E, 0x8D, 0xAC, 0x74, 0x15,
      0xB7, 0x59, 0xC4, 0xA8, 0x9F, 0x0A, 0x72, 0x9E,
      0x7E, 0x6E, 0x15, 0x47, 0x22, 0xDF, 0x12, 0x34,
      0x58, 0x35, 0x07, 0x6A, 0x99, 0xCF, 0x34, 0xDC,
      0x6E, 0x22, 0x50, 0xC9, 0xDE, 0xC0, 0x68, 0x9B,
      0x65, 0x89, 0xBC, 0xD4, 0xDB, 0xED, 0xF8, 0xAB,
      0xC8, 0x12, 0xA8, 0xA2, 0x2B, 0x0D, 0x40, 0x52,
      0xDC, 0xBB, 0xFE, 0x02, 0x32, 0x2F, 0xA4, 0xA9,
      0xCA, 0xD7, 0x10, 0x61, 0x21, 0x1E, 0xF0, 0xB4,
      0xD3, 0x50, 0x5D, 0x04, 0x0F, 0xF6, 0x00, 0xC2,
      0x6F, 0x16, 0x9D, 0x25, 0x36, 0x86, 0x42, 0x56,
      0x4A, 0x55, 0x5E, 0x09, 0xC1, 0xBE, 0xE0, 0x91
  };
  
  
  
  int twofish_init(cipher_context_t *context, const uint8_t *key,
                   uint8_t keySize)
  {
      uint8_t i;
  
      // Make sure that context is large enough. If this is not the case,
      // you should build with -DTWOFISH.
      if(CIPHER_MAX_CONTEXT_SIZE < TWOFISH_CONTEXT_SIZE) {
          return CIPHER_ERR_BAD_CONTEXT_SIZE;
      }
  
      //key must be at least CIPHERS_MAX_KEY_SIZE Bytes long
      if (keySize < CIPHERS_MAX_KEY_SIZE) {
          //fill up by concatenating key to as long as needed
          for (i = 0; i < CIPHERS_MAX_KEY_SIZE; i++) {
              context->context[i] = key[(i % keySize)];
          }
      }
      else {
          for (i = 0; i < CIPHERS_MAX_KEY_SIZE; i++) {
              context->context[i] = key[i];
          }
      }
  
      return CIPHER_INIT_SUCCESS;
  }
  
  /**
   * @brief Perform the key setup.
   *        Note that this works only with 128- and 256-bit keys, despite the
   *        API that looks like it might support other sizes.
   *
   * @param ctx       pointer to the context that the setup will be executed on
   * @param key       pointer to the key
   * @param keylen    length of the key in bytes
   *
   * @return  -1 if invalid key-length, 0 otherwise
   */
  static int twofish_setup_key(twofish_context_t *ctx, const uint8_t *key, uint8_t keylen)
  {
      int i, j, k;
  
      /* Temporaries for CALC_K. */
      /* cppcheck: used in macros in sys/include/crypto/twofish.h that cppcheck
       * doesn't understand
       */
      /* cppcheck-suppress unusedVariable */
      uint32_t x, y;
  
      /* The S vector used to key the S-boxes, split up into individual bytes.
       * 128-bit keys use only sa through sh; 256-bit use all of them. */
      uint8_t sa = 0, sb = 0, sc = 0, sd = 0, se = 0, sf = 0, sg = 0, sh = 0;
      /* cppcheck: moving this may introduce timing vulnerability */
      /* cppcheck-suppress variableScope */
      uint8_t si = 0, sj = 0, sk = 0, sl = 0, sm = 0, sn = 0, so = 0, sp = 0;
  
      /* Temporary for CALC_S. */
      /* cppcheck: used in macros in sys/include/crypto/twofish.h that cppcheck
       * doesn't understand
       */
      /* cppcheck-suppress unusedVariable */
      uint8_t tmp;
  
      /* Check key length. */
      if (((keylen - 16) | 16) != 16) {
          DEBUG("%s:%d in %s: [ERROR] invalid key-length!\r\n", RIOT_FILE_RELATIVE,
                __LINE__, DEBUG_FUNC);
          return -1;
      }
  
  
      /* Compute the first two words of the S vector.  The magic numbers are
       * the entries of the RS matrix, preprocessed through poly_to_exp. The
       * numbers in the comments are the original (polynomial form) matrix
       * entries. */
      CALC_S(sa, sb, sc, sd, 0, 0x00, 0x2D, 0x01, 0x2D);  /* 01 A4 02 A4 */
      CALC_S(sa, sb, sc, sd, 1, 0x2D, 0xA4, 0x44, 0x8A);  /* A4 56 A1 55 */
      CALC_S(sa, sb, sc, sd, 2, 0x8A, 0xD5, 0xBF, 0xD1);  /* 55 82 FC 87 */
      CALC_S(sa, sb, sc, sd, 3, 0xD1, 0x7F, 0x3D, 0x99);  /* 87 F3 C1 5A */
      CALC_S(sa, sb, sc, sd, 4, 0x99, 0x46, 0x66, 0x96);  /* 5A 1E 47 58 */
      CALC_S(sa, sb, sc, sd, 5, 0x96, 0x3C, 0x5B, 0xED);  /* 58 C6 AE DB */
      CALC_S(sa, sb, sc, sd, 6, 0xED, 0x37, 0x4F, 0xE0);  /* DB 68 3D 9E */
      CALC_S(sa, sb, sc, sd, 7, 0xE0, 0xD0, 0x8C, 0x17);  /* 9E E5 19 03 */
      CALC_S(se, sf, sg, sh, 8, 0x00, 0x2D, 0x01, 0x2D);  /* 01 A4 02 A4 */
      CALC_S(se, sf, sg, sh, 9, 0x2D, 0xA4, 0x44, 0x8A);  /* A4 56 A1 55 */
      CALC_S(se, sf, sg, sh, 10, 0x8A, 0xD5, 0xBF, 0xD1); /* 55 82 FC 87 */
      CALC_S(se, sf, sg, sh, 11, 0xD1, 0x7F, 0x3D, 0x99); /* 87 F3 C1 5A */
      CALC_S(se, sf, sg, sh, 12, 0x99, 0x46, 0x66, 0x96); /* 5A 1E 47 58 */
      CALC_S(se, sf, sg, sh, 13, 0x96, 0x3C, 0x5B, 0xED); /* 58 C6 AE DB */
      CALC_S(se, sf, sg, sh, 14, 0xED, 0x37, 0x4F, 0xE0); /* DB 68 3D 9E */
      CALC_S(se, sf, sg, sh, 15, 0xE0, 0xD0, 0x8C, 0x17); /* 9E E5 19 03 */
  
      if (keylen == 32) { /* 256-bit key */
          /* Calculate the remaining two words of the S vector */
          CALC_S(si, sj, sk, sl, 16, 0x00, 0x2D, 0x01, 0x2D);  /* 01 A4 02 A4 */
          CALC_S(si, sj, sk, sl, 17, 0x2D, 0xA4, 0x44, 0x8A);  /* A4 56 A1 55 */
          CALC_S(si, sj, sk, sl, 18, 0x8A, 0xD5, 0xBF, 0xD1);  /* 55 82 FC 87 */
          CALC_S(si, sj, sk, sl, 19, 0xD1, 0x7F, 0x3D, 0x99);  /* 87 F3 C1 5A */
          CALC_S(si, sj, sk, sl, 20, 0x99, 0x46, 0x66, 0x96);  /* 5A 1E 47 58 */
          CALC_S(si, sj, sk, sl, 21, 0x96, 0x3C, 0x5B, 0xED);  /* 58 C6 AE DB */
          CALC_S(si, sj, sk, sl, 22, 0xED, 0x37, 0x4F, 0xE0);  /* DB 68 3D 9E */
          CALC_S(si, sj, sk, sl, 23, 0xE0, 0xD0, 0x8C, 0x17);  /* 9E E5 19 03 */
          CALC_S(sm, sn, so, sp, 24, 0x00, 0x2D, 0x01, 0x2D);  /* 01 A4 02 A4 */
          CALC_S(sm, sn, so, sp, 25, 0x2D, 0xA4, 0x44, 0x8A);  /* A4 56 A1 55 */
          CALC_S(sm, sn, so, sp, 26, 0x8A, 0xD5, 0xBF, 0xD1);  /* 55 82 FC 87 */
          CALC_S(sm, sn, so, sp, 27, 0xD1, 0x7F, 0x3D, 0x99);  /* 87 F3 C1 5A */
          CALC_S(sm, sn, so, sp, 28, 0x99, 0x46, 0x66, 0x96);  /* 5A 1E 47 58 */
          CALC_S(sm, sn, so, sp, 29, 0x96, 0x3C, 0x5B, 0xED);  /* 58 C6 AE DB */
          CALC_S(sm, sn, so, sp, 30, 0xED, 0x37, 0x4F, 0xE0);  /* DB 68 3D 9E */
          CALC_S(sm, sn, so, sp, 31, 0xE0, 0xD0, 0x8C, 0x17);  /* 9E E5 19 03 */
  
          /* Compute the S-boxes. */
          for (i = j = 0, k = 1; i < 256; i++, j += 2, k += 2) {
              CALC_SB256_2(i, calc_sb_tbl[j], calc_sb_tbl[k]);
          }
  
          /*
           * Calculate whitening and round subkeys. The constants are
           * indices of subkeys, preprocessed through q0 and q1.
           *
           **/
          CALC_K256(w, 0, 0xA9, 0x75, 0x67, 0xF3);
          CALC_K256(w, 2, 0xB3, 0xC6, 0xE8, 0xF4);
          CALC_K256(w, 4, 0x04, 0xDB, 0xFD, 0x7B);
          CALC_K256(w, 6, 0xA3, 0xFB, 0x76, 0xC8);
          CALC_K256(k, 0, 0x9A, 0x4A, 0x92, 0xD3);
          CALC_K256(k, 2, 0x80, 0xE6, 0x78, 0x6B);
          CALC_K256(k, 4, 0xE4, 0x45, 0xDD, 0x7D);
          CALC_K256(k, 6, 0xD1, 0xE8, 0x38, 0x4B);
          CALC_K256(k, 8, 0x0D, 0xD6, 0xC6, 0x32);
          CALC_K256(k, 10, 0x35, 0xD8, 0x98, 0xFD);
          CALC_K256(k, 12, 0x18, 0x37, 0xF7, 0x71);
          CALC_K256(k, 14, 0xEC, 0xF1, 0x6C, 0xE1);
          CALC_K256(k, 16, 0x43, 0x30, 0x75, 0x0F);
          CALC_K256(k, 18, 0x37, 0xF8, 0x26, 0x1B);
          CALC_K256(k, 20, 0xFA, 0x87, 0x13, 0xFA);
          CALC_K256(k, 22, 0x94, 0x06, 0x48, 0x3F);
          CALC_K256(k, 24, 0xF2, 0x5E, 0xD0, 0xBA);
          CALC_K256(k, 26, 0x8B, 0xAE, 0x30, 0x5B);
          CALC_K256(k, 28, 0x84, 0x8A, 0x54, 0x00);
          CALC_K256(k, 30, 0xDF, 0xBC, 0x23, 0x9D);
      }
      else {
          /* Compute the S-boxes. */
          for (i = j = 0, k = 1; i < 256; i++, j += 2, k += 2) {
              CALC_SB_2(i, calc_sb_tbl[j], calc_sb_tbl[k]);
          }
  
          /*
           * Calculate whitening and round subkeys. The constants are
           * indices of subkeys, preprocessed through q0 and q1.
           **/
          CALC_K(w, 0, 0xA9, 0x75, 0x67, 0xF3);
          CALC_K(w, 2, 0xB3, 0xC6, 0xE8, 0xF4);
          CALC_K(w, 4, 0x04, 0xDB, 0xFD, 0x7B);
          CALC_K(w, 6, 0xA3, 0xFB, 0x76, 0xC8);
          CALC_K(k, 0, 0x9A, 0x4A, 0x92, 0xD3);
          CALC_K(k, 2, 0x80, 0xE6, 0x78, 0x6B);
          CALC_K(k, 4, 0xE4, 0x45, 0xDD, 0x7D);
          CALC_K(k, 6, 0xD1, 0xE8, 0x38, 0x4B);
          CALC_K(k, 8, 0x0D, 0xD6, 0xC6, 0x32);
          CALC_K(k, 10, 0x35, 0xD8, 0x98, 0xFD);
          CALC_K(k, 12, 0x18, 0x37, 0xF7, 0x71);
          CALC_K(k, 14, 0xEC, 0xF1, 0x6C, 0xE1);
          CALC_K(k, 16, 0x43, 0x30, 0x75, 0x0F);
          CALC_K(k, 18, 0x37, 0xF8, 0x26, 0x1B);
          CALC_K(k, 20, 0xFA, 0x87, 0x13, 0xFA);
          CALC_K(k, 22, 0x94, 0x06, 0x48, 0x3F);
          CALC_K(k, 24, 0xF2, 0x5E, 0xD0, 0xBA);
          CALC_K(k, 26, 0x8B, 0xAE, 0x30, 0x5B);
          CALC_K(k, 28, 0x84, 0x8A, 0x54, 0x00);
          CALC_K(k, 30, 0xDF, 0xBC, 0x23, 0x9D);
      }
  
      return 0;
  }
  
  
  /* Encrypt one block.  in and out may be the same. */
  int twofish_encrypt(const cipher_context_t *context, const uint8_t *in, uint8_t *out)
  {
      int res;
      //setup the twofish-specific context
      twofish_context_t *ctx = malloc(sizeof(twofish_context_t));
  
      if (!ctx) {
          DEBUG("%s:%d in %s: [ERROR] Could NOT malloc space for the twofish_context_t \
                  struct.\r\n", RIOT_FILE_RELATIVE, __LINE__, DEBUG_FUNC);
          return -1;
      }
  
      res = twofish_setup_key(ctx, context->context, TWOFISH_KEY_SIZE);
  
      if (res < 0) {
          DEBUG("%s:%d in %s: [ERROR] twofish_setKey failed with Code %i\r\n",
                RIOT_FILE_RELATIVE, __LINE__, DEBUG_FUNC, res);
          free(ctx);
          return -2;
      }
  
      /* The four 32-bit chunks of the text. */
      uint32_t a, b, c, d;
  
      /* Temporaries used by the round function. */
      /* cppcheck: used in macros in sys/include/crypto/twofish.h that cppcheck
       * doesn't understand
       */
      /* cppcheck-suppress unusedVariable */
      uint32_t x, y;
  
      /* Input whitening and packing. */
      INPACK(0, a, 0);
      INPACK(1, b, 1);
      INPACK(2, c, 2);
      INPACK(3, d, 3);
  
      /* Encryption Feistel cycles. */
      ENCCYCLE(0);
      ENCCYCLE(1);
      ENCCYCLE(2);
      ENCCYCLE(3);
      ENCCYCLE(4);
      ENCCYCLE(5);
      ENCCYCLE(6);
      ENCCYCLE(7);
  
      /* Output whitening and unpacking. */
      OUTUNPACK(0, c, 4);
      OUTUNPACK(1, d, 5);
      OUTUNPACK(2, a, 6);
      OUTUNPACK(3, b, 7);
  
      free(ctx);
      return 1;
  }
  
  /* Decrypt one block.  in and out may be the same. */
  int twofish_decrypt(const cipher_context_t *context, const uint8_t *in, uint8_t *out)
  {
      int res;
      twofish_context_t *ctx = malloc(sizeof(twofish_context_t));
  
      if (!ctx) {
          DEBUG("%s:%d in %s: [ERROR] Could NOT malloc space for the twofish_context_t \
                  struct.\r\n", RIOT_FILE_RELATIVE, __LINE__, DEBUG_FUNC);
          return -1;
      }
  
      res = twofish_setup_key(ctx, context->context, TWOFISH_KEY_SIZE);
  
      if (res < 0) {
          DEBUG("%s:%d in %s: [ERROR] twofish_setKey failed with Code %i\r\n",
                RIOT_FILE_RELATIVE, __LINE__, DEBUG_FUNC, res);
          free(ctx);
          return -2;
      }
  
      /* The four 32-bit chunks of the text. */
      uint32_t a, b, c, d;
  
      /* Temporaries used by the round function. */
      /* cppcheck: used in macros in sys/include/crypto/twofish.h that cppcheck
       * doesn't understand
       */
      /* cppcheck-suppress unusedVariable */
      uint32_t x, y;
  
      /* Input whitening and packing. */
      INPACK(0, c, 4);
      INPACK(1, d, 5);
      INPACK(2, a, 6);
      INPACK(3, b, 7);
  
      /* Encryption Feistel cycles. */
      DECCYCLE(7);
      DECCYCLE(6);
      DECCYCLE(5);
      DECCYCLE(4);
      DECCYCLE(3);
      DECCYCLE(2);
      DECCYCLE(1);
      DECCYCLE(0);
  
      /* Output whitening and unpacking. */
      OUTUNPACK(0, a, 0);
      OUTUNPACK(1, b, 1);
      OUTUNPACK(2, c, 2);
      OUTUNPACK(3, d, 3);
  
      free(ctx);
      return 1;
  }