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  •  * The serpent block cipher.
    
     *
     * For more details on this algorithm, see the Serpent website at
     * http://www.cl.cam.ac.uk/~rja14/serpent.html
     */
    
    
    /* nettle, low-level cryptographics library
     *
     * Copyright (C) 1998, 2000, 2001, Ross Anderson, Eli Biham, Lars
     *                                 Knudsen, Rafael R. Sevilla, Niels Mller
    
     * This program is free software; you can redistribute it and/or
     * modify it under the terms of the GNU General Public License as
     * published by the Free Software Foundation; either version 2 of the
     * License, or (at your option) any later version.
    
     * This program is distributed in the hope that it will be useful, but
     * WITHOUT ANY WARRANTY; without even the implied warranty of
     * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
     * General Public License for more details.
    
     * You should have received a copy of the GNU General Public License
     * along with this program; if not, write to the Free Software
     * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
    
    /* I've modified this code a bit so that it interoperates with lsh
     * properly. 2000-9-5, Rafael R. Sevilla <dido@pacific.net.ph>
     */
    
    /* NOTE: The copyright notice for the original version of this code
     * said "All rights reserved. This code is freely distributed for AES
     * selection process. No other use is allowed." However, the authors
     * later decided to GPL the code. /nisse */
    
    
    /* FIXME: Use the READ_UINT32 and WRITE_UINT32 macros, where
     * applicable. */
    
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    #include "serpent.h"
    
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    #include "serpent_sboxes.h"
    
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    void
    
    serpent_set_key(struct serpent_ctx *ctx,
    
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                    unsigned key_size, const uint8_t *key)
    
      uint32_t w[132], k[132];
    
      assert(key_size >= SERPENT_MIN_KEY_SIZE);
      assert(key_size <= SERPENT_MAX_KEY_SIZE);
    
      for (i = key_size, j = 0;
           (i >= 4);
    
          /* Read the key in the reverse direction. Why? */
          w[j] = READ_UINT32(key + i - 4);
    
          /* Pad key, "aabbccddeeff" -> 0xccddeeff, 0x01aabb" */
    
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          uint32_t partial = 0x01;
    
    	partial = (partial << 8 ) | *key++;
    
          w[j++] = partial;
    
          while (j < 8)
    	w[j++] = 0;
        }  
    
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      for(i=8; i<16; i++)
        w[i]=ROL(w[i-8]^w[i-5]^w[i-3]^w[i-1]^PHI^(i-8),11);
      for(i=0; i<8; i++)
        w[i]=w[i+8];
      for(i=8; i<132; i++)
        w[i]=ROL(w[i-8]^w[i-5]^w[i-3]^w[i-1]^PHI^i,11);
    
      RND03(w[  0], w[  1], w[  2], w[  3], k[  0], k[  1], k[  2], k[  3]);
      RND02(w[  4], w[  5], w[  6], w[  7], k[  4], k[  5], k[  6], k[  7]);
      RND01(w[  8], w[  9], w[ 10], w[ 11], k[  8], k[  9], k[ 10], k[ 11]);
      RND00(w[ 12], w[ 13], w[ 14], w[ 15], k[ 12], k[ 13], k[ 14], k[ 15]);
      RND31(w[ 16], w[ 17], w[ 18], w[ 19], k[ 16], k[ 17], k[ 18], k[ 19]);
      RND30(w[ 20], w[ 21], w[ 22], w[ 23], k[ 20], k[ 21], k[ 22], k[ 23]);
      RND29(w[ 24], w[ 25], w[ 26], w[ 27], k[ 24], k[ 25], k[ 26], k[ 27]);
      RND28(w[ 28], w[ 29], w[ 30], w[ 31], k[ 28], k[ 29], k[ 30], k[ 31]);
      RND27(w[ 32], w[ 33], w[ 34], w[ 35], k[ 32], k[ 33], k[ 34], k[ 35]);
      RND26(w[ 36], w[ 37], w[ 38], w[ 39], k[ 36], k[ 37], k[ 38], k[ 39]);
      RND25(w[ 40], w[ 41], w[ 42], w[ 43], k[ 40], k[ 41], k[ 42], k[ 43]);
      RND24(w[ 44], w[ 45], w[ 46], w[ 47], k[ 44], k[ 45], k[ 46], k[ 47]);
      RND23(w[ 48], w[ 49], w[ 50], w[ 51], k[ 48], k[ 49], k[ 50], k[ 51]);
      RND22(w[ 52], w[ 53], w[ 54], w[ 55], k[ 52], k[ 53], k[ 54], k[ 55]);
      RND21(w[ 56], w[ 57], w[ 58], w[ 59], k[ 56], k[ 57], k[ 58], k[ 59]);
      RND20(w[ 60], w[ 61], w[ 62], w[ 63], k[ 60], k[ 61], k[ 62], k[ 63]);
      RND19(w[ 64], w[ 65], w[ 66], w[ 67], k[ 64], k[ 65], k[ 66], k[ 67]);
      RND18(w[ 68], w[ 69], w[ 70], w[ 71], k[ 68], k[ 69], k[ 70], k[ 71]);
      RND17(w[ 72], w[ 73], w[ 74], w[ 75], k[ 72], k[ 73], k[ 74], k[ 75]);
      RND16(w[ 76], w[ 77], w[ 78], w[ 79], k[ 76], k[ 77], k[ 78], k[ 79]);
      RND15(w[ 80], w[ 81], w[ 82], w[ 83], k[ 80], k[ 81], k[ 82], k[ 83]);
      RND14(w[ 84], w[ 85], w[ 86], w[ 87], k[ 84], k[ 85], k[ 86], k[ 87]);
      RND13(w[ 88], w[ 89], w[ 90], w[ 91], k[ 88], k[ 89], k[ 90], k[ 91]);
      RND12(w[ 92], w[ 93], w[ 94], w[ 95], k[ 92], k[ 93], k[ 94], k[ 95]);
      RND11(w[ 96], w[ 97], w[ 98], w[ 99], k[ 96], k[ 97], k[ 98], k[ 99]);
      RND10(w[100], w[101], w[102], w[103], k[100], k[101], k[102], k[103]);
      RND09(w[104], w[105], w[106], w[107], k[104], k[105], k[106], k[107]);
      RND08(w[108], w[109], w[110], w[111], k[108], k[109], k[110], k[111]);
      RND07(w[112], w[113], w[114], w[115], k[112], k[113], k[114], k[115]);
      RND06(w[116], w[117], w[118], w[119], k[116], k[117], k[118], k[119]);
      RND05(w[120], w[121], w[122], w[123], k[120], k[121], k[122], k[123]);
      RND04(w[124], w[125], w[126], w[127], k[124], k[125], k[126], k[127]);
      RND03(w[128], w[129], w[130], w[131], k[128], k[129], k[130], k[131]);
    
    
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        for(j=0; j<4; j++)
          ctx->keys[i][j] = k[4*i+j];
    }
    
    void
    
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    serpent_encrypt(struct serpent_ctx *ctx,
    
                    unsigned length, uint8_t *dst,
                    const uint8_t *plain)
    
      register uint32_t x0, x1, x2, x3;
      register uint32_t y0, y1, y2, y3;
    
    
      FOR_BLOCKS(length, dst, plain, SERPENT_BLOCK_SIZE)
    
          /* Why the reverse order? */
          x0=READ_UINT32(plain + 12);
          x1=READ_UINT32(plain + 8);
          x2=READ_UINT32(plain + 4);
          x3=READ_UINT32(plain);
    
          /* Start to encrypt the plaintext x */
          keying(x0, x1, x2, x3, ctx->keys[ 0]);
          RND00(x0, x1, x2, x3, y0, y1, y2, y3);
          transform(y0, y1, y2, y3, x0, x1, x2, x3);
          keying(x0, x1, x2, x3, ctx->keys[ 1]);
          RND01(x0, x1, x2, x3, y0, y1, y2, y3);
          transform(y0, y1, y2, y3, x0, x1, x2, x3);
          keying(x0, x1, x2, x3, ctx->keys[ 2]);
          RND02(x0, x1, x2, x3, y0, y1, y2, y3);
          transform(y0, y1, y2, y3, x0, x1, x2, x3);
          keying(x0, x1, x2, x3, ctx->keys[ 3]);
          RND03(x0, x1, x2, x3, y0, y1, y2, y3);
          transform(y0, y1, y2, y3, x0, x1, x2, x3);
          keying(x0, x1, x2, x3, ctx->keys[ 4]);
          RND04(x0, x1, x2, x3, y0, y1, y2, y3);
          transform(y0, y1, y2, y3, x0, x1, x2, x3);
          keying(x0, x1, x2, x3, ctx->keys[ 5]);
          RND05(x0, x1, x2, x3, y0, y1, y2, y3);
          transform(y0, y1, y2, y3, x0, x1, x2, x3);
          keying(x0, x1, x2, x3, ctx->keys[ 6]);
          RND06(x0, x1, x2, x3, y0, y1, y2, y3);
          transform(y0, y1, y2, y3, x0, x1, x2, x3);
          keying(x0, x1, x2, x3, ctx->keys[ 7]);
          RND07(x0, x1, x2, x3, y0, y1, y2, y3);
          transform(y0, y1, y2, y3, x0, x1, x2, x3);
          keying(x0, x1, x2, x3, ctx->keys[ 8]);
          RND08(x0, x1, x2, x3, y0, y1, y2, y3);
          transform(y0, y1, y2, y3, x0, x1, x2, x3);
          keying(x0, x1, x2, x3, ctx->keys[ 9]);
          RND09(x0, x1, x2, x3, y0, y1, y2, y3);
          transform(y0, y1, y2, y3, x0, x1, x2, x3);
          keying(x0, x1, x2, x3, ctx->keys[10]);
          RND10(x0, x1, x2, x3, y0, y1, y2, y3);
          transform(y0, y1, y2, y3, x0, x1, x2, x3);
          keying(x0, x1, x2, x3, ctx->keys[11]);
          RND11(x0, x1, x2, x3, y0, y1, y2, y3);
          transform(y0, y1, y2, y3, x0, x1, x2, x3);
          keying(x0, x1, x2, x3, ctx->keys[12]);
          RND12(x0, x1, x2, x3, y0, y1, y2, y3);
          transform(y0, y1, y2, y3, x0, x1, x2, x3);
          keying(x0, x1, x2, x3, ctx->keys[13]);
          RND13(x0, x1, x2, x3, y0, y1, y2, y3);
          transform(y0, y1, y2, y3, x0, x1, x2, x3);
          keying(x0, x1, x2, x3, ctx->keys[14]);
          RND14(x0, x1, x2, x3, y0, y1, y2, y3);
          transform(y0, y1, y2, y3, x0, x1, x2, x3);
          keying(x0, x1, x2, x3, ctx->keys[15]);
          RND15(x0, x1, x2, x3, y0, y1, y2, y3);
          transform(y0, y1, y2, y3, x0, x1, x2, x3);
          keying(x0, x1, x2, x3, ctx->keys[16]);
          RND16(x0, x1, x2, x3, y0, y1, y2, y3);
          transform(y0, y1, y2, y3, x0, x1, x2, x3);
          keying(x0, x1, x2, x3, ctx->keys[17]);
          RND17(x0, x1, x2, x3, y0, y1, y2, y3);
          transform(y0, y1, y2, y3, x0, x1, x2, x3);
          keying(x0, x1, x2, x3, ctx->keys[18]);
          RND18(x0, x1, x2, x3, y0, y1, y2, y3);
          transform(y0, y1, y2, y3, x0, x1, x2, x3);
          keying(x0, x1, x2, x3, ctx->keys[19]);
          RND19(x0, x1, x2, x3, y0, y1, y2, y3);
          transform(y0, y1, y2, y3, x0, x1, x2, x3);
          keying(x0, x1, x2, x3, ctx->keys[20]);
          RND20(x0, x1, x2, x3, y0, y1, y2, y3);
          transform(y0, y1, y2, y3, x0, x1, x2, x3);
          keying(x0, x1, x2, x3, ctx->keys[21]);
          RND21(x0, x1, x2, x3, y0, y1, y2, y3);
          transform(y0, y1, y2, y3, x0, x1, x2, x3);
          keying(x0, x1, x2, x3, ctx->keys[22]);
          RND22(x0, x1, x2, x3, y0, y1, y2, y3);
          transform(y0, y1, y2, y3, x0, x1, x2, x3);
          keying(x0, x1, x2, x3, ctx->keys[23]);
          RND23(x0, x1, x2, x3, y0, y1, y2, y3);
          transform(y0, y1, y2, y3, x0, x1, x2, x3);
          keying(x0, x1, x2, x3, ctx->keys[24]);
          RND24(x0, x1, x2, x3, y0, y1, y2, y3);
          transform(y0, y1, y2, y3, x0, x1, x2, x3);
          keying(x0, x1, x2, x3, ctx->keys[25]);
          RND25(x0, x1, x2, x3, y0, y1, y2, y3);
          transform(y0, y1, y2, y3, x0, x1, x2, x3);
          keying(x0, x1, x2, x3, ctx->keys[26]);
          RND26(x0, x1, x2, x3, y0, y1, y2, y3);
          transform(y0, y1, y2, y3, x0, x1, x2, x3);
          keying(x0, x1, x2, x3, ctx->keys[27]);
          RND27(x0, x1, x2, x3, y0, y1, y2, y3);
          transform(y0, y1, y2, y3, x0, x1, x2, x3);
          keying(x0, x1, x2, x3, ctx->keys[28]);
          RND28(x0, x1, x2, x3, y0, y1, y2, y3);
          transform(y0, y1, y2, y3, x0, x1, x2, x3);
          keying(x0, x1, x2, x3, ctx->keys[29]);
          RND29(x0, x1, x2, x3, y0, y1, y2, y3);
          transform(y0, y1, y2, y3, x0, x1, x2, x3);
          keying(x0, x1, x2, x3, ctx->keys[30]);
          RND30(x0, x1, x2, x3, y0, y1, y2, y3);
          transform(y0, y1, y2, y3, x0, x1, x2, x3);
          keying(x0, x1, x2, x3, ctx->keys[31]);
          RND31(x0, x1, x2, x3, y0, y1, y2, y3);
          x0 = y0; x1 = y1; x2 = y2; x3 = y3;
          keying(x0, x1, x2, x3, ctx->keys[32]);
    
          /* The ciphertext is now in x */
    
          /* Why the reverse order? */
          WRITE_UINT32(dst, x3);
          WRITE_UINT32(dst+4, x2);
          WRITE_UINT32(dst+8, x1);
          WRITE_UINT32(dst+12, x0);
    
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    serpent_decrypt(struct serpent_ctx *ctx,
    
                    unsigned length, uint8_t *dst,
    
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                    const uint8_t *cipher)
    
      register uint32_t x0, x1, x2, x3;
      register uint32_t y0, y1, y2, y3;
    
      FOR_BLOCKS(length, dst, cipher, SERPENT_BLOCK_SIZE)
    
          /* Why the reverse order? */
          x0 = READ_UINT32(cipher + 12);
          x1 = READ_UINT32(cipher + 8);
          x2 = READ_UINT32(cipher + 4);
          x3 = READ_UINT32(cipher);
          
    
          /* Start to decrypt the ciphertext x */
          keying(x0, x1, x2, x3, ctx->keys[32]);
          InvRND31(x0, x1, x2, x3, y0, y1, y2, y3);
          keying(y0, y1, y2, y3, ctx->keys[31]);
          inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
          InvRND30(x0, x1, x2, x3, y0, y1, y2, y3);
          keying(y0, y1, y2, y3, ctx->keys[30]);
          inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
          InvRND29(x0, x1, x2, x3, y0, y1, y2, y3);
          keying(y0, y1, y2, y3, ctx->keys[29]);
          inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
          InvRND28(x0, x1, x2, x3, y0, y1, y2, y3);
          keying(y0, y1, y2, y3, ctx->keys[28]);
          inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
          InvRND27(x0, x1, x2, x3, y0, y1, y2, y3);
          keying(y0, y1, y2, y3, ctx->keys[27]);
          inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
          InvRND26(x0, x1, x2, x3, y0, y1, y2, y3);
          keying(y0, y1, y2, y3, ctx->keys[26]);
          inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
          InvRND25(x0, x1, x2, x3, y0, y1, y2, y3);
          keying(y0, y1, y2, y3, ctx->keys[25]);
          inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
          InvRND24(x0, x1, x2, x3, y0, y1, y2, y3);
          keying(y0, y1, y2, y3, ctx->keys[24]);
          inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
          InvRND23(x0, x1, x2, x3, y0, y1, y2, y3);
          keying(y0, y1, y2, y3, ctx->keys[23]);
          inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
          InvRND22(x0, x1, x2, x3, y0, y1, y2, y3);
          keying(y0, y1, y2, y3, ctx->keys[22]);
          inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
          InvRND21(x0, x1, x2, x3, y0, y1, y2, y3);
          keying(y0, y1, y2, y3, ctx->keys[21]);
          inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
          InvRND20(x0, x1, x2, x3, y0, y1, y2, y3);
          keying(y0, y1, y2, y3, ctx->keys[20]);
          inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
          InvRND19(x0, x1, x2, x3, y0, y1, y2, y3);
          keying(y0, y1, y2, y3, ctx->keys[19]);
          inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
          InvRND18(x0, x1, x2, x3, y0, y1, y2, y3);
          keying(y0, y1, y2, y3, ctx->keys[18]);
          inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
          InvRND17(x0, x1, x2, x3, y0, y1, y2, y3);
          keying(y0, y1, y2, y3, ctx->keys[17]);
          inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
          InvRND16(x0, x1, x2, x3, y0, y1, y2, y3);
          keying(y0, y1, y2, y3, ctx->keys[16]);
          inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
          InvRND15(x0, x1, x2, x3, y0, y1, y2, y3);
          keying(y0, y1, y2, y3, ctx->keys[15]);
          inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
          InvRND14(x0, x1, x2, x3, y0, y1, y2, y3);
          keying(y0, y1, y2, y3, ctx->keys[14]);
          inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
          InvRND13(x0, x1, x2, x3, y0, y1, y2, y3);
          keying(y0, y1, y2, y3, ctx->keys[13]);
          inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
          InvRND12(x0, x1, x2, x3, y0, y1, y2, y3);
          keying(y0, y1, y2, y3, ctx->keys[12]);
          inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
          InvRND11(x0, x1, x2, x3, y0, y1, y2, y3);
          keying(y0, y1, y2, y3, ctx->keys[11]);
          inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
          InvRND10(x0, x1, x2, x3, y0, y1, y2, y3);
          keying(y0, y1, y2, y3, ctx->keys[10]);
          inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
          InvRND09(x0, x1, x2, x3, y0, y1, y2, y3);
          keying(y0, y1, y2, y3, ctx->keys[ 9]);
          inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
          InvRND08(x0, x1, x2, x3, y0, y1, y2, y3);
          keying(y0, y1, y2, y3, ctx->keys[ 8]);
          inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
          InvRND07(x0, x1, x2, x3, y0, y1, y2, y3);
          keying(y0, y1, y2, y3, ctx->keys[ 7]);
          inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
          InvRND06(x0, x1, x2, x3, y0, y1, y2, y3);
          keying(y0, y1, y2, y3, ctx->keys[ 6]);
          inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
          InvRND05(x0, x1, x2, x3, y0, y1, y2, y3);
          keying(y0, y1, y2, y3, ctx->keys[ 5]);
          inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
          InvRND04(x0, x1, x2, x3, y0, y1, y2, y3);
          keying(y0, y1, y2, y3, ctx->keys[ 4]);
          inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
          InvRND03(x0, x1, x2, x3, y0, y1, y2, y3);
          keying(y0, y1, y2, y3, ctx->keys[ 3]);
          inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
          InvRND02(x0, x1, x2, x3, y0, y1, y2, y3);
          keying(y0, y1, y2, y3, ctx->keys[ 2]);
          inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
          InvRND01(x0, x1, x2, x3, y0, y1, y2, y3);
          keying(y0, y1, y2, y3, ctx->keys[ 1]);
          inv_transform(y0, y1, y2, y3, x0, x1, x2, x3);
          InvRND00(x0, x1, x2, x3, y0, y1, y2, y3);
          x0 = y0; x1 = y1; x2 = y2; x3 = y3;
          keying(x0, x1, x2, x3, ctx->keys[ 0]);
    
          /* The plaintext is now in x */
    
          /* Why the reverse order? */
          WRITE_UINT32(dst, x3);
          WRITE_UINT32(dst+4, x2);
          WRITE_UINT32(dst+8, x1);
          WRITE_UINT32(dst+12, x0);