/* This file is derived from sober128 implementation in corosync
   cluster engine. corosync cluster engine borrows the implementation
   from LibTomCrypt.

   The latest version of the original code can be found at
   http://www.libtom.net/LibTomCrypt/ according to which this code is in the
   Public Domain
   */

/* About LibTomCrypt:
 * ---------------------------------------------------------------------
 * LibTomCrypt, modular cryptographic library -- Tom St Denis
 *
 * LibTomCrypt is a library that provides various cryptographic
 * algorithms in a highly modular and flexible manner.
 *
 * The library is free for all purposes without any express
 * guarantee it works.
 *
 * Tom St Denis, tomstdenis@iahu.ca, http://www.libtom.net/LibTomCrypt/
 */

#include "sober128.h"

typedef unsigned long ulong32;
typedef unsigned long long ulong64;

/* ---- HELPER MACROS ---- */
#define STORE32L(x, y)                                                                     \
     { (y)[3] = (unsigned char)(((x)>>24)&255); (y)[2] = (unsigned char)(((x)>>16)&255);   \
       (y)[1] = (unsigned char)(((x)>>8)&255); (y)[0] = (unsigned char)((x)&255); }

#define LOAD32L(x, y)                            \
     { x = ((unsigned long)((y)[3] & 255)<<24) | \
           ((unsigned long)((y)[2] & 255)<<16) | \
           ((unsigned long)((y)[1] & 255)<<8)  | \
           ((unsigned long)((y)[0] & 255)); }

/* rotates the hard way */
#define ROR(x, y) ( ((((unsigned long)(x)&0xFFFFFFFFUL)>>(unsigned long)((y)&31)) | ((unsigned long)(x)<<(unsigned long)(32-((y)&31)))) & 0xFFFFFFFFUL)


/* Id: s128multab.h 213 2003-12-16 04:27:12Z ggr $ */
/* @(#)TuringMultab.h   1.3 (QUALCOMM) 02/09/03 */
/* Multiplication table for Turing using 0xD02B4367 */

static const ulong32 Multab[256] = {
    0x00000000, 0xD02B4367, 0xED5686CE, 0x3D7DC5A9,
    0x97AC41D1, 0x478702B6, 0x7AFAC71F, 0xAAD18478,
    0x631582EF, 0xB33EC188, 0x8E430421, 0x5E684746,
    0xF4B9C33E, 0x24928059, 0x19EF45F0, 0xC9C40697,
    0xC62A4993, 0x16010AF4, 0x2B7CCF5D, 0xFB578C3A,
    0x51860842, 0x81AD4B25, 0xBCD08E8C, 0x6CFBCDEB,
    0xA53FCB7C, 0x7514881B, 0x48694DB2, 0x98420ED5,
    0x32938AAD, 0xE2B8C9CA, 0xDFC50C63, 0x0FEE4F04,
    0xC154926B, 0x117FD10C, 0x2C0214A5, 0xFC2957C2,
    0x56F8D3BA, 0x86D390DD, 0xBBAE5574, 0x6B851613,
    0xA2411084, 0x726A53E3, 0x4F17964A, 0x9F3CD52D,
    0x35ED5155, 0xE5C61232, 0xD8BBD79B, 0x089094FC,
    0x077EDBF8, 0xD755989F, 0xEA285D36, 0x3A031E51,
    0x90D29A29, 0x40F9D94E, 0x7D841CE7, 0xADAF5F80,
    0x646B5917, 0xB4401A70, 0x893DDFD9, 0x59169CBE,
    0xF3C718C6, 0x23EC5BA1, 0x1E919E08, 0xCEBADD6F,
    0xCFA869D6, 0x1F832AB1, 0x22FEEF18, 0xF2D5AC7F,
    0x58042807, 0x882F6B60, 0xB552AEC9, 0x6579EDAE,
    0xACBDEB39, 0x7C96A85E, 0x41EB6DF7, 0x91C02E90,
    0x3B11AAE8, 0xEB3AE98F, 0xD6472C26, 0x066C6F41,
    0x09822045, 0xD9A96322, 0xE4D4A68B, 0x34FFE5EC,
    0x9E2E6194, 0x4E0522F3, 0x7378E75A, 0xA353A43D,
    0x6A97A2AA, 0xBABCE1CD, 0x87C12464, 0x57EA6703,
    0xFD3BE37B, 0x2D10A01C, 0x106D65B5, 0xC04626D2,
    0x0EFCFBBD, 0xDED7B8DA, 0xE3AA7D73, 0x33813E14,
    0x9950BA6C, 0x497BF90B, 0x74063CA2, 0xA42D7FC5,
    0x6DE97952, 0xBDC23A35, 0x80BFFF9C, 0x5094BCFB,
    0xFA453883, 0x2A6E7BE4, 0x1713BE4D, 0xC738FD2A,
    0xC8D6B22E, 0x18FDF149, 0x258034E0, 0xF5AB7787,
    0x5F7AF3FF, 0x8F51B098, 0xB22C7531, 0x62073656,
    0xABC330C1, 0x7BE873A6, 0x4695B60F, 0x96BEF568,
    0x3C6F7110, 0xEC443277, 0xD139F7DE, 0x0112B4B9,
    0xD31DD2E1, 0x03369186, 0x3E4B542F, 0xEE601748,
    0x44B19330, 0x949AD057, 0xA9E715FE, 0x79CC5699,
    0xB008500E, 0x60231369, 0x5D5ED6C0, 0x8D7595A7,
    0x27A411DF, 0xF78F52B8, 0xCAF29711, 0x1AD9D476,
    0x15379B72, 0xC51CD815, 0xF8611DBC, 0x284A5EDB,
    0x829BDAA3, 0x52B099C4, 0x6FCD5C6D, 0xBFE61F0A,
    0x7622199D, 0xA6095AFA, 0x9B749F53, 0x4B5FDC34,
    0xE18E584C, 0x31A51B2B, 0x0CD8DE82, 0xDCF39DE5,
    0x1249408A, 0xC26203ED, 0xFF1FC644, 0x2F348523,
    0x85E5015B, 0x55CE423C, 0x68B38795, 0xB898C4F2,
    0x715CC265, 0xA1778102, 0x9C0A44AB, 0x4C2107CC,
    0xE6F083B4, 0x36DBC0D3, 0x0BA6057A, 0xDB8D461D,
    0xD4630919, 0x04484A7E, 0x39358FD7, 0xE91ECCB0,
    0x43CF48C8, 0x93E40BAF, 0xAE99CE06, 0x7EB28D61,
    0xB7768BF6, 0x675DC891, 0x5A200D38, 0x8A0B4E5F,
    0x20DACA27, 0xF0F18940, 0xCD8C4CE9, 0x1DA70F8E,
    0x1CB5BB37, 0xCC9EF850, 0xF1E33DF9, 0x21C87E9E,
    0x8B19FAE6, 0x5B32B981, 0x664F7C28, 0xB6643F4F,
    0x7FA039D8, 0xAF8B7ABF, 0x92F6BF16, 0x42DDFC71,
    0xE80C7809, 0x38273B6E, 0x055AFEC7, 0xD571BDA0,
    0xDA9FF2A4, 0x0AB4B1C3, 0x37C9746A, 0xE7E2370D,
    0x4D33B375, 0x9D18F012, 0xA06535BB, 0x704E76DC,
    0xB98A704B, 0x69A1332C, 0x54DCF685, 0x84F7B5E2,
    0x2E26319A, 0xFE0D72FD, 0xC370B754, 0x135BF433,
    0xDDE1295C, 0x0DCA6A3B, 0x30B7AF92, 0xE09CECF5,
    0x4A4D688D, 0x9A662BEA, 0xA71BEE43, 0x7730AD24,
    0xBEF4ABB3, 0x6EDFE8D4, 0x53A22D7D, 0x83896E1A,
    0x2958EA62, 0xF973A905, 0xC40E6CAC, 0x14252FCB,
    0x1BCB60CF, 0xCBE023A8, 0xF69DE601, 0x26B6A566,
    0x8C67211E, 0x5C4C6279, 0x6131A7D0, 0xB11AE4B7,
    0x78DEE220, 0xA8F5A147, 0x958864EE, 0x45A32789,
    0xEF72A3F1, 0x3F59E096, 0x0224253F, 0xD20F6658,
};

/* Id: s128sbox.h 213 2003-12-16 04:27:12Z ggr $ */
/* Sbox for SOBER-128 */
/*
 * This is really the combination of two SBoxes; the least significant
 * 24 bits comes from:
 * 8->32 Sbox generated by Millan et. al. at Queensland University of
 * Technology. See: E. Dawson, W. Millan, L. Burnett, G. Carter,
 * "On the Design of 8*32 S-boxes". Unpublished report, by the
 * Information Systems Research Centre,
 * Queensland University of Technology, 1999.
 *
 * The most significant 8 bits are the Skipjack "F table", which can be
 * found at http://csrc.nist.gov/CryptoToolkit/skipjack/skipjack.pdf .
 * In this optimised table, though, the intent is to XOR the word from
 * the table selected by the high byte with the input word. Thus, the
 * high byte is actually the Skipjack F-table entry XORED with its
 * table index.
 */
static const ulong32 Sbox[256] = {
    0xa3aa1887, 0xd65e435c, 0x0b65c042, 0x800e6ef4,
    0xfc57ee20, 0x4d84fed3, 0xf066c502, 0xf354e8ae,
    0xbb2ee9d9, 0x281f38d4, 0x1f829b5d, 0x735cdf3c,
    0x95864249, 0xbc2e3963, 0xa1f4429f, 0xf6432c35,
    0xf7f40325, 0x3cc0dd70, 0x5f973ded, 0x9902dc5e,
    0xda175b42, 0x590012bf, 0xdc94d78c, 0x39aab26b,
    0x4ac11b9a, 0x8c168146, 0xc3ea8ec5, 0x058ac28f,
    0x52ed5c0f, 0x25b4101c, 0x5a2db082, 0x370929e1,
    0x2a1843de, 0xfe8299fc, 0x202fbc4b, 0x833915dd,
    0x33a803fa, 0xd446b2de, 0x46233342, 0x4fcee7c3,
    0x3ad607ef, 0x9e97ebab, 0x507f859b, 0xe81f2e2f,
    0xc55b71da, 0xd7e2269a, 0x1339c3d1, 0x7ca56b36,
    0xa6c9def2, 0xb5c9fc5f, 0x5927b3a3, 0x89a56ddf,
    0xc625b510, 0x560f85a7, 0xace82e71, 0x2ecb8816,
    0x44951e2a, 0x97f5f6af, 0xdfcbc2b3, 0xce4ff55d,
    0xcb6b6214, 0x2b0b83e3, 0x549ea6f5, 0x9de041af,
    0x792f1f17, 0xf73b99ee, 0x39a65ec0, 0x4c7016c6,
    0x857709a4, 0xd6326e01, 0xc7b280d9, 0x5cfb1418,
    0xa6aff227, 0xfd548203, 0x506b9d96, 0xa117a8c0,
    0x9cd5bf6e, 0xdcee7888, 0x61fcfe64, 0xf7a193cd,
    0x050d0184, 0xe8ae4930, 0x88014f36, 0xd6a87088,
    0x6bad6c2a, 0x1422c678, 0xe9204de7, 0xb7c2e759,
    0x0200248e, 0x013b446b, 0xda0d9fc2, 0x0414a895,
    0x3a6cc3a1, 0x56fef170, 0x86c19155, 0xcf7b8a66,
    0x551b5e69, 0xb4a8623e, 0xa2bdfa35, 0xc4f068cc,
    0x573a6acd, 0x6355e936, 0x03602db9, 0x0edf13c1,
    0x2d0bb16d, 0x6980b83c, 0xfeb23763, 0x3dd8a911,
    0x01b6bc13, 0xf55579d7, 0xf55c2fa8, 0x19f4196e,
    0xe7db5476, 0x8d64a866, 0xc06e16ad, 0xb17fc515,
    0xc46feb3c, 0x8bc8a306, 0xad6799d9, 0x571a9133,
    0x992466dd, 0x92eb5dcd, 0xac118f50, 0x9fafb226,
    0xa1b9cef3, 0x3ab36189, 0x347a19b1, 0x62c73084,
    0xc27ded5c, 0x6c8bc58f, 0x1cdde421, 0xed1e47fb,
    0xcdcc715e, 0xb9c0ff99, 0x4b122f0f, 0xc4d25184,
    0xaf7a5e6c, 0x5bbf18bc, 0x8dd7c6e0, 0x5fb7e420,
    0x521f523f, 0x4ad9b8a2, 0xe9da1a6b, 0x97888c02,
    0x19d1e354, 0x5aba7d79, 0xa2cc7753, 0x8c2d9655,
    0x19829da1, 0x531590a7, 0x19c1c149, 0x3d537f1c,
    0x50779b69, 0xed71f2b7, 0x463c58fa, 0x52dc4418,
    0xc18c8c76, 0xc120d9f0, 0xafa80d4d, 0x3b74c473,
    0xd09410e9, 0x290e4211, 0xc3c8082b, 0x8f6b334a,
    0x3bf68ed2, 0xa843cc1b, 0x8d3c0ff3, 0x20e564a0,
    0xf8f55a4f, 0x2b40f8e7, 0xfea7f15f, 0xcf00fe21,
    0x8a6d37d6, 0xd0d506f1, 0xade00973, 0xefbbde36,
    0x84670fa8, 0xfa31ab9e, 0xaedab618, 0xc01f52f5,
    0x6558eb4f, 0x71b9e343, 0x4b8d77dd, 0x8cb93da6,
    0x740fd52d, 0x425412f8, 0xc5a63360, 0x10e53ad0,
    0x5a700f1c, 0x8324ed0b, 0xe53dc1ec, 0x1a366795,
    0x6d549d15, 0xc5ce46d7, 0xe17abe76, 0x5f48e0a0,
    0xd0f07c02, 0x941249b7, 0xe49ed6ba, 0x37a47f78,
    0xe1cfffbd, 0xb007ca84, 0xbb65f4da, 0xb59f35da,
    0x33d2aa44, 0x417452ac, 0xc0d674a7, 0x2d61a46a,
    0xdc63152a, 0x3e12b7aa, 0x6e615927, 0xa14fb118,
    0xa151758d, 0xba81687b, 0xe152f0b3, 0x764254ed,
    0x34c77271, 0x0a31acab, 0x54f94aec, 0xb9e994cd,
    0x574d9e81, 0x5b623730, 0xce8a21e8, 0x37917f0b,
    0xe8a9b5d6, 0x9697adf8, 0xf3d30431, 0x5dcac921,
    0x76b35d46, 0xaa430a36, 0xc2194022, 0x22bca65e,
    0xdaec70ba, 0xdfaea8cc, 0x777bae8b, 0x242924d5,
    0x1f098a5a, 0x4b396b81, 0x55de2522, 0x435c1cb8,
    0xaeb8fe1d, 0x9db3c697, 0x5b164f83, 0xe0c16376,
    0xa319224c, 0xd0203b35, 0x433ac0fe, 0x1466a19a,
    0x45f0b24f, 0x51fda998, 0xc0d52d71, 0xfa0896a8,
    0xf9e6053f, 0xa4b0d300, 0xd499cbcc, 0xb95e3d40,
};


/* Implementation of SOBER-128 by Tom St Denis.
 * Based on s128fast.c reference code supplied by Greg Rose of QUALCOMM.
 */

/* don't change these... */
#define N                        17
#define FOLD                      N /* how many iterations of folding to do */
#define INITKONST        0x6996c53a /* value of KONST to use during key loading */
#define KEYP                     15 /* where to insert key words */
#define FOLDP                     4 /* where to insert non-linear feedback */

static ulong32 BYTE2WORD(const unsigned char *b)
{
   ulong32 t;
   LOAD32L(t, b);
   return t;
}

static void XORWORD(ulong32 w, unsigned char *b)
{
   ulong32 t;
   LOAD32L(t, b);
   t ^= w;
   STORE32L(t, b);
}

/* give correct offset for the current position of the register,
 * where logically R[0] is at position "zero".
 */
#define OFF(zero, i) (((zero)+(i)) % N)

/* step the LFSR */
/* After stepping, "zero" moves right one place */
#define STEP(R,z) \
    R[OFF(z,0)] = R[OFF(z,15)] ^ R[OFF(z,4)] ^ (R[OFF(z,0)] << 8) ^ Multab[(R[OFF(z,0)] >> 24) & 0xFF];

static void cycle(ulong32 *R)
{
    ulong32 t;
    int     i;

    STEP(R,0);
    t = R[0];
    for (i = 1; i < N; ++i) {
        R[i-1] = R[i];
    }
    R[N-1] = t;
}

/* Return a non-linear function of some parts of the register.
 */
#define NLFUNC(c,z) \
{ \
    t = c->R[OFF(z,0)] + c->R[OFF(z,16)]; \
    t ^= Sbox[(t >> 24) & 0xFF]; \
    t = ROR(t, 8); \
    t = ((t + c->R[OFF(z,1)]) ^ c->konst) + c->R[OFF(z,6)]; \
    t ^= Sbox[(t >> 24) & 0xFF]; \
    t = t + c->R[OFF(z,13)]; \
}

static ulong32 nltap(sober128_prng *c)
{
    ulong32 t;
    NLFUNC(c, 0);
    return t;
}

/* initialise to known state
 */
int sober128_start(sober128_prng *c)
{
    int                   i;

    /* Register initialised to Fibonacci numbers */
    c->R[0] = 1;
    c->R[1] = 1;
    for (i = 2; i < N; ++i) {
       c->R[i] = c->R[i-1] + c->R[i-2];
    }
    c->konst = INITKONST;

    /* next add_entropy will be the key */
    c->flag  = 1;
    c->set   = 0;

    return 0;
}

/* Save the current register state
 */
static void s128_savestate(sober128_prng *c)
{
    int i;
    for (i = 0; i < N; ++i) {
        c->initR[i] = c->R[i];
    }
}

/* initialise to previously saved register state
 */
static void s128_reloadstate(sober128_prng *c)
{
    int i;

    for (i = 0; i < N; ++i) {
        c->R[i] = c->initR[i];
    }
}

/* Initialise "konst"
 */
static void s128_genkonst(sober128_prng *c)
{
    ulong32 newkonst;

    do {
       cycle(c->R);
       newkonst = nltap(c);
    } while ((newkonst & 0xFF000000) == 0);
    c->konst = newkonst;
}

/* Load key material into the register
 */
#define ADDKEY(k) \
   c->R[KEYP] += (k);

#define XORNL(nl) \
   c->R[FOLDP] ^= (nl);

/* nonlinear diffusion of register for key */
#define DROUND(z) STEP(c->R,z); NLFUNC(c,(z+1)); c->R[OFF((z+1),FOLDP)] ^= t;
static void s128_diffuse(sober128_prng *c)
{
    ulong32 t;
    /* relies on FOLD == N == 17! */
    DROUND(0);
    DROUND(1);
    DROUND(2);
    DROUND(3);
    DROUND(4);
    DROUND(5);
    DROUND(6);
    DROUND(7);
    DROUND(8);
    DROUND(9);
    DROUND(10);
    DROUND(11);
    DROUND(12);
    DROUND(13);
    DROUND(14);
    DROUND(15);
    DROUND(16);
}

int sober128_add_entropy(const unsigned char *buf, unsigned long len, sober128_prng *c)
{
    ulong32               i, k;


    if (c->flag == 1) {
       /* this is the first call to the add_entropy so this input is the key */
       /* len must be multiple of 4 bytes */
       /* assert ((len & 3) == 0); */

       for (i = 0; i < len/4; i++) {
           k = BYTE2WORD(&buf[i*4]);
          ADDKEY(k);
          cycle(c->R);
          XORNL(nltap(c));
       }

       /* also fold in the length of the key */
       ADDKEY(len);

       /* now diffuse */
       s128_diffuse(c);

       s128_genkonst(c);
       s128_savestate(c);
       c->nbuf = 0;
       c->flag = 0;
       c->set  = 1;
    } else {
       /* ok we are adding an IV then... */
       s128_reloadstate(c);

       /* len must be multiple of 4 bytes */
       /* assert ((len & 3) == 0); */

       for (i = 0; i < len/4; i++) {
           k = BYTE2WORD(&buf[i*4]);
          ADDKEY(k);
          cycle(c->R);
          XORNL(nltap(c));
       }

       /* also fold in the length of the key */
       ADDKEY(len);

       /* now diffuse */
       s128_diffuse(c);
       c->nbuf = 0;
    }

    return 0;
}

/* XOR pseudo-random bytes into buffer
 */
#define SROUND(z) STEP(c->R,z); NLFUNC(c,(z+1)); XORWORD(t, buf+(z*4));

unsigned long sober128_read(unsigned char *buf, unsigned long nbytes, sober128_prng *c)
{
   ulong32               t, tlen;

   tlen = nbytes;

   /* handle any previously buffered bytes */
   while (c->nbuf != 0 && nbytes != 0) {
      *buf++ ^= c->sbuf & 0xFF;
       c->sbuf >>= 8;
       c->nbuf -= 8;
       --nbytes;
   }

#ifndef SMALL_CODE
    /* do lots at a time, if there's enough to do */
    while (nbytes >= N*4) {
      SROUND(0);
      SROUND(1);
      SROUND(2);
      SROUND(3);
      SROUND(4);
      SROUND(5);
      SROUND(6);
      SROUND(7);
      SROUND(8);
      SROUND(9);
      SROUND(10);
      SROUND(11);
      SROUND(12);
      SROUND(13);
      SROUND(14);
      SROUND(15);
      SROUND(16);
      buf    += 4*N;
      nbytes -= 4*N;
    }
#endif

    /* do small or odd size buffers the slow way */
    while (4 <= nbytes) {
      cycle(c->R);
      t = nltap(c);
      XORWORD(t, buf);
      buf    += 4;
      nbytes -= 4;
    }

    /* handle any trailing bytes */
    if (nbytes != 0) {
      cycle(c->R);
      c->sbuf = nltap(c);
      c->nbuf = 32;
      while (c->nbuf != 0 && nbytes != 0) {
        *buf++ ^= c->sbuf & 0xFF;
        c->sbuf >>= 8;
        c->nbuf -= 8;
        --nbytes;
      }
    }

    return tlen;
}

/*
 * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
 *
 * Local variables:
 * c-basic-offset: 4
 * tab-width: 8
 * indent-tabs-mode: nil
 * End:
 *
 * vi: set shiftwidth=4 tabstop=8 expandtab:
 * :indentSize=4:tabSize=8:noTabs=true:
 */
