sflcryp.c

短小精悍的C语言标准函数库。提供450个以上的可移植的算法和工具代码。

    0x00002000L, 0x04002000L, 0x00042000L, 0x04042000L,
    0x00002002L, 0x04002002L, 0x00042002L, 0x04042002L,
    0x00000020L, 0x04000020L, 0x00040020L, 0x04040020L,
    0x00000022L, 0x04000022L, 0x00040022L, 0x04040022L,
    0x00002020L, 0x04002020L, 0x00042020L, 0x04042020L,
    0x00002022L, 0x04002022L, 0x00042022L, 0x04042022L,
    0x00000800L, 0x04000800L, 0x00040800L, 0x04040800L,
    0x00000802L, 0x04000802L, 0x00040802L, 0x04040802L,
    0x00002800L, 0x04002800L, 0x00042800L, 0x04042800L,
    0x00002802L, 0x04002802L, 0x00042802L, 0x04042802L,
    0x00000820L, 0x04000820L, 0x00040820L, 0x04040820L,
    0x00000822L, 0x04000822L, 0x00040822L, 0x04040822L,
    0x00002820L, 0x04002820L, 0x00042820L, 0x04042820L,
    0x00002822L, 0x04002822L, 0x00042822L, 0x04042822L } };



/*  -------------------------------------------------------------------------
    Function: des_ecb_encrypt - internal

    Synopsis: main function for DES cipher

    input   : pointer to an 8 byte block to be encrypted/decrypted
    output  : pointer to an 8 byte block to hold the results of the
             encryption/decryption
    ks      : pointer to the des_key_schedule structure that you were given
              by the des_key_sched() function
    encrypt : TRUE if you encrypting, FALSE if you are decrypting
    -------------------------------------------------------------------------*/

static int
des_ecb_encrypt (des_cblock *input, des_cblock *output,
                 des_key_schedule *ks, int encrypt)
{
    static qbyte
        l0, l1,
        ll [2];
    static byte
        *in,
        *out;

    in  = (byte *)input;
    out = (byte *)output;
    c2l (in,l0);
    c2l (in,l1);
    ll [0] = l0;
    ll [1] = l1;
    des_encrypt ((qbyte *) ll, (qbyte *) ll, ks, encrypt);
    l0 = ll [0];
    l1 = ll [1];
    l2c (l0, out);
    l2c (l1, out);

    return (0);
}


/*  -------------------------------------------------------------------------
    Function: des_encrypt - internal

    Synopsis:
    -------------------------------------------------------------------------*/

static int
des_encrypt (qbyte *input, qbyte *output, des_key_schedule *ks, int encrypt)
{
    static qbyte
        l, r, *s, t, u;
#ifdef ALT_ECB
    static byte
        *des_SP = (byte *) des_SPtrans;
#endif
    static int
        i;

    l = input [0];
    r = input [1];

    /*  do IP */
    PERM_OP (r, l, t, 4 , 0x0f0f0f0fL);
    PERM_OP (l, r, t, 16, 0x0000ffffL);
    PERM_OP (r, l, t, 2 , 0x33333333L);
    PERM_OP (l, r, t, 8 , 0x00ff00ffL);
    PERM_OP (r, l, t, 1 , 0x55555555L);

    t = (r << 1)|(r >> 31);
    r = (l << 1)|(l >> 31);
    l = t;

    /*  Clear the top bits on machines with 8byte longs                      */
    l &= 0xffffffffL;
    r &= 0xffffffffL;

    s = (qbyte *) ks;

    if (encrypt)
      {
        for (i = 0; i < 32; i += 4)
          {
            D_ENCRYPT (l, r, i + 0);    /*  1                                */
            D_ENCRYPT (r, l, i + 2);    /*  2                                */
          }
      }
    else
      {
        for (i = 30; i > 0; i -= 4)
          {
            D_ENCRYPT (l, r, i - 0);    /*  16                               */
            D_ENCRYPT (r, l, i - 2);    /*  15                               */
          }
      }
    l = (l >> 1)|(l << 31);
    r = (r >> 1)|(r << 31);

    /*  Clear the top bits on machines with 8byte longs                      */
    l &= 0xffffffffL;
    r &= 0xffffffffL;

    PERM_OP (r, l, t, 1 , 0x55555555L);
    PERM_OP (l, r, t, 8 , 0x00ff00ffL);
    PERM_OP (r, l, t, 2 , 0x33333333L);
    PERM_OP (l, r, t, 16, 0x0000ffffL);
    PERM_OP (r, l, t, 4 , 0x0f0f0f0fL);

    output [0] = l;
    output [1] = r;

    return(0);
}


/*  -------------------------------------------------------------------------
    Function: des_set_key - internal

    Synopsis:
    -------------------------------------------------------------------------*/

static int
des_set_key (des_cblock *key, des_key_schedule *schedule)
{
    static qbyte
        c, d, t, s, *k;
    static byte
        *in;
    static int
        index;
    static char
        shifts2 [16] = {0, 0, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 0};

    k  = (qbyte *) schedule;
    in = (byte *) key;

    c2l (in, c);
    c2l (in, d);

    PERM_OP  (d, c, t , 4, 0x0f0f0f0fL);
    HPERM_OP (c, t, -2,    0xcccc0000L);
    HPERM_OP (d, t, -2,    0xcccc0000L);
    PERM_OP  (d, c, t , 1, 0x55555555L);
    PERM_OP  (c, d, t , 8, 0x00ff00ffL);
    PERM_OP  (d, c, t , 1, 0x55555555L);
    d =    (((d & 0x000000ffL) << 16)| (d & 0x0000ff00L)      |
            ((d & 0x00ff0000L) >> 16)|((c & 0xf0000000L) >> 4));
    c &= 0x0fffffffL;

    for (index = 0; index < ITERATIONS; index++)
      {
        if (shifts2 [index])
          {
            c = ((c >> 2) | (c << 26));
            d = ((d >> 2) | (d << 26));
          }
        else
          {
            c = ((c >> 1) | (c << 27));
            d = ((d >> 1) | (d << 27));
          }
        c &= 0x0fffffffL;
        d &= 0x0fffffffL;

        /*  Could be a few less shifts but I am to lazy at this point in     */
        /*  time to investigate                                              */
        s = des_skb [0] [(word) ((c)        & 0x3f                      )] |
            des_skb [1] [(word) (((c >>  6) & 0x03) | ((c >>  7) & 0x3c))] |
            des_skb [2] [(word) (((c >> 13) & 0x0f) | ((c >> 14) & 0x30))] |
            des_skb [3] [(word) (((c >> 20) & 0x01) | ((c >> 21) & 0x06)   |
                                                      ((c >> 22) & 0x38))];

        t = des_skb [4] [(word) (((d)       & 0x3f)                     )] |
            des_skb [5] [(word) (((d >>  7) & 0x03) | ((d >>  8) & 0x3c))] |
            des_skb [6] [(word) (((d >> 15) & 0x3f)                     )] |
            des_skb [7] [(word) (((d >> 21) & 0x0f) | ((d >> 22) & 0x30))];

        /*  Table contained 0213 4657                                        */
        *(k++) = ((t << 16) | (s & 0x0000ffffL)) & 0xffffffffL;
        s      = ((s >> 16) | (t & 0xffff0000L));
        s      =  (s << 4)  | (s >> 28);
        *(k++) = s & 0xffffffffL;
      }
    return(0);
}


/*  -------------------------------------------------------------------------
    Function: des_key_sched - internal

    Synopsis: You need to call this function before you use the des_ecb_encrypt
              function to operate on your data. It performs some initial
              operations on your key, presumably to make the operation of the
              cipher faster.

              Always returns zero.

        key   : pointer to a 64 bit key. a `des_cblock' is simply an 8-byte
                unsigned character array so you can just pass the address of
                an 8 bytes array as this parameter.

        sched : pointer to an address of a des_key_schedule structure that the
                function will fill in with the DES key schedule information
                that you will need to pass to the encryption/decryption
                function.

    -------------------------------------------------------------------------*/

static int
des_key_sched (des_cblock *key, des_key_schedule *schedule)
{
    return (des_set_key (key, schedule));
}


/*  -------------------------------------------------------------------------
    Function: xor_crypt - internal

    Synopsis: Encrypts / decrypts a 16-byte block using a 16-byte key.
    -------------------------------------------------------------------------*/

static void
xor_crypt (byte *buffer, const byte *key)
{
    buffer  [0] ^= key  [0];
    buffer  [1] ^= key  [1];
    buffer  [2] ^= key  [2];
    buffer  [3] ^= key  [3];
    buffer  [4] ^= key  [4];
    buffer  [5] ^= key  [5];
    buffer  [6] ^= key  [6];
    buffer  [7] ^= key  [7];
    buffer  [8] ^= key  [8];
    buffer  [9] ^= key  [9];
    buffer [10] ^= key [10];
    buffer [11] ^= key [11];
    buffer [12] ^= key [12];
    buffer [13] ^= key [13];
    buffer [14] ^= key [14];
    buffer [15] ^= key [15];
}


static qbyte crc_table [] = {
    0x00000000L, 0x77073096L, 0xEE0E612CL, 0x990951BAL,
    0x076DC419L, 0x706AF48FL, 0xE963A535L, 0x9E6495A3L,
    0x0EDB8832L, 0x79DCB8A4L, 0xE0D5E91EL, 0x97D2D988L,
    0x09B64C2BL, 0x7EB17CBDL, 0xE7B82D07L, 0x90BF1D91L,
    0x1DB71064L, 0x6AB020F2L, 0xF3B97148L, 0x84BE41DEL,
    0x1ADAD47DL, 0x6DDDE4EBL, 0xF4D4B551L, 0x83D385C7L,
    0x136C9856L, 0x646BA8C0L, 0xFD62F97AL, 0x8A65C9ECL,
    0x14015C4FL, 0x63066CD9L, 0xFA0F3D63L, 0x8D080DF5L,
    0x3B6E20C8L, 0x4C69105EL, 0xD56041E4L, 0xA2677172L,
    0x3C03E4D1L, 0x4B04D447L, 0xD20D85FDL, 0xA50AB56BL,
    0x35B5A8FAL, 0x42B2986CL, 0xDBBBC9D6L, 0xACBCF940L,
    0x32D86CE3L, 0x45DF5C75L, 0xDCD60DCFL, 0xABD13D59L,
    0x26D930ACL, 0x51DE003AL, 0xC8D75180L, 0xBFD06116L,
    0x21B4F4B5L, 0x56B3C423L, 0xCFBA9599L, 0xB8BDA50FL,
    0x2802B89EL, 0x5F058808L, 0xC60CD9B2L, 0xB10BE924L,
    0x2F6F7C87L, 0x58684C11L, 0xC1611DABL, 0xB6662D3DL,
    0x76DC4190L, 0x01DB7106L, 0x98D220BCL, 0xEFD5102AL,
    0x71B18589L, 0x06B6B51FL, 0x9FBFE4A5L, 0xE8B8D433L,
    0x7807C9A2L, 0x0F00F934L, 0x9609A88EL, 0xE10E9818L,
    0x7F6A0DBBL, 0x086D3D2DL, 0x91646C97L, 0xE6635C01L,
    0x6B6B51F4L, 0x1C6C6162L, 0x856530D8L, 0xF262004EL,
    0x6C0695EDL, 0x1B01A57BL, 0x8208F4C1L, 0xF50FC457L,
    0x65B0D9C6L, 0x12B7E950L, 0x8BBEB8EAL, 0xFCB9887CL,
    0x62DD1DDFL, 0x15DA2D49L, 0x8CD37CF3L, 0xFBD44C65L,
    0x4DB26158L, 0x3AB551CEL, 0xA3BC0074L, 0xD4BB30E2L,
    0x4ADFA541L, 0x3DD895D7L, 0xA4D1C46DL, 0xD3D6F4FBL,
    0x4369E96AL, 0x346ED9FCL, 0xAD678846L, 0xDA60B8D0L,
    0x44042D73L, 0x33031DE5L, 0xAA0A4C5FL, 0xDD0D7CC9L,
    0x5005713CL, 0x270241AAL, 0xBE0B1010L, 0xC90C2086L,
    0x5768B525L, 0x206F85B3L, 0xB966D409L, 0xCE61E49FL,
    0x5EDEF90EL, 0x29D9C998L, 0xB0D09822L, 0xC7D7A8B4L,
    0x59B33D17L, 0x2EB40D81L, 0xB7BD5C3BL, 0xC0BA6CADL,
    0xEDB88320L, 0x9ABFB3B6L, 0x03B6E20CL, 0x74B1D29AL,
    0xEAD54739L, 0x9DD277AFL, 0x04DB2615L, 0x73DC1683L,
    0xE3630B12L, 0x94643B84L, 0x0D6D6A3EL, 0x7A6A5AA8L,
    0xE40ECF0BL, 0x9309FF9DL, 0x0A00AE27L, 0x7D079EB1L,
    0xF00F9344L, 0x8708A3D2L, 0x1E01F268L, 0x6906C2FEL,
    0xF762575DL, 0x806567CBL, 0x196C3671L, 0x6E6B06E7L,
    0xFED41B76L, 0x89D32BE0L, 0x10DA7A5AL, 0x67DD4ACCL,
    0xF9B9DF6FL, 0x8EBEEFF9L, 0x17B7BE43L, 0x60B08ED5L,
    0xD6D6A3E8L, 0xA1D1937EL, 0x38D8C2C4L, 0x4FDFF252L,
    0xD1BB67F1L, 0xA6BC5767L, 0x3FB506DDL, 0x48B2364BL,
    0xD80D2BDAL, 0xAF0A1B4CL, 0x36034AF6L, 0x41047A60L,
    0xDF60EFC3L, 0xA867DF55L, 0x316E8EEFL, 0x4669BE79L,
    0xCB61B38CL, 0xBC66831AL, 0x256FD2A0L, 0x5268E236L,
    0xCC0C7795L, 0xBB0B4703L, 0x220216B9L, 0x5505262FL,
    0xC5BA3BBEL, 0xB2BD0B28L, 0x2BB45A92L, 0x5CB36A04L,
    0xC2D7FFA7L, 0xB5D0CF31L, 0x2CD99E8BL, 0x5BDEAE1DL,
    0x9B64C2B0L, 0xEC63F226L, 0x756AA39CL, 0x026D930AL,
    0x9C0906A9L, 0xEB0E363FL, 0x72076785L, 0x05005713L,
    0x95BF4A82L, 0xE2B87A14L, 0x7BB12BAEL, 0x0CB61B38L,
    0x92D28E9BL, 0xE5D5BE0DL, 0x7CDCEFB7L, 0x0BDBDF21L,
    0x86D3D2D4L, 0xF1D4E242L, 0x68DDB3F8L, 0x1FDA836EL,
    0x81BE16CDL, 0xF6B9265BL, 0x6FB077E1L, 0x18B74777L,
    0x88085AE6L, 0xFF0F6A70L, 0x66063BCAL, 0x11010B5CL,
    0x8F659EFFL, 0xF862AE69L, 0x616BFFD3L, 0x166CCF45L,
    0xA00AE278L, 0xD70DD2EEL, 0x4E048354L, 0x3903B3C2L,
    0xA7672661L, 0xD06016F7L, 0x4969474DL, 0x3E6E77DBL,
    0xAED16A4AL, 0xD9D65ADCL, 0x40DF0B66L, 0x37D83BF0L,
    0xA9BCAE53L, 0xDEBB9EC5L, 0x47B2CF7FL, 0x30B5FFE9L,
    0xBDBDF21CL, 0xCABAC28AL, 0x53B39330L, 0x24B4A3A6L,
    0xBAD03605L, 0xCDD70693L, 0x54DE5729L, 0x23D967BFL,
    0xB3667A2EL, 0xC4614AB8L, 0x5D681B02L, 0x2A6F2B94L,
    0xB40BBE37L, 0xC30C8EA1L, 0x5A05DF1BL, 0x2D02EF8DL
};


/*  ---------------------------------------------------------------------[<]-
    Function: calculate_crc

    Synopsis: Calculates the 32-bit CCITT CRC for a memory block.  The CRC
    calculation is rapid, since the function uses a pre-calculated table.
    Returns the 32-bit CRC.
    ---------------------------------------------------------------------[>]-*/

qbyte
calculate_crc (byte *block, size_t length)
{
    size_t
        offset;
    word
        this_word;
    qbyte
        crc_value;                      /*  Running CRC value                */

    crc_value = 0xFFFFFFFFL;
    for (offset = 0; offset < length; offset++)
    {
        this_word = block [offset];
        this_word = this_word ^ (dbyte) (crc_value & 255);
        crc_value = (crc_value >> 8) ^ crc_table [this_word];
    }
    return (crc_value ^ 0xFFFFFFFFL);
}