Mercurial > dropbear
view libtomcrypt/src/prngs/sober128.c @ 712:bf0ac0512ef7
Fix "-m none" case and ugly typo
author | Matt Johnston <matt@ucc.asn.au> |
---|---|
date | Wed, 20 Mar 2013 23:13:45 +0800 |
parents | 0cbe8f6dbf9e |
children | f849a5ca2efc |
line wrap: on
line source
/* 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, [email protected], http://libtomcrypt.com */ #include "tomcrypt.h" /** @file sober128.c Implementation of SOBER-128 by Tom St Denis. Based on s128fast.c reference code supplied by Greg Rose of QUALCOMM. */ #ifdef SOBER128 #include "sober128tab.c" const struct ltc_prng_descriptor sober128_desc = { "sober128", 64, &sober128_start, &sober128_add_entropy, &sober128_ready, &sober128_read, &sober128_done, &sober128_export, &sober128_import, &sober128_test }; /* 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 */ #define B(x,i) ((unsigned char)(((x) >> (8*i)) & 0xFF)) static ulong32 BYTE2WORD(unsigned char *b) { ulong32 t; LOAD32L(t, b); return t; } #define WORD2BYTE(w, b) STORE32L(b, w) 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 = RORc(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(struct sober128_prng *c) { ulong32 t; NLFUNC(c, 0); return t; } /** Start the PRNG @param prng [out] The PRNG state to initialize @return CRYPT_OK if successful */ int sober128_start(prng_state *prng) { int i; struct sober128_prng *c; LTC_ARGCHK(prng != NULL); c = &(prng->sober128); /* 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 CRYPT_OK; } /* Save the current register state */ static void s128_savestate(struct 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(struct sober128_prng *c) { int i; for (i = 0; i < N; ++i) { c->R[i] = c->initR[i]; } } /* Initialise "konst" */ static void s128_genkonst(struct 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(struct 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); } /** Add entropy to the PRNG state @param in The data to add @param inlen Length of the data to add @param prng PRNG state to update @return CRYPT_OK if successful */ int sober128_add_entropy(const unsigned char *in, unsigned long inlen, prng_state *prng) { struct sober128_prng *c; ulong32 i, k; LTC_ARGCHK(in != NULL); LTC_ARGCHK(prng != NULL); c = &(prng->sober128); if (c->flag == 1) { /* this is the first call to the add_entropy so this input is the key */ /* inlen must be multiple of 4 bytes */ if ((inlen & 3) != 0) { return CRYPT_INVALID_KEYSIZE; } for (i = 0; i < inlen; i += 4) { k = BYTE2WORD((unsigned char *)&in[i]); ADDKEY(k); cycle(c->R); XORNL(nltap(c)); } /* also fold in the length of the key */ ADDKEY(inlen); /* 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); /* inlen must be multiple of 4 bytes */ if ((inlen & 3) != 0) { return CRYPT_INVALID_KEYSIZE; } for (i = 0; i < inlen; i += 4) { k = BYTE2WORD((unsigned char *)&in[i]); ADDKEY(k); cycle(c->R); XORNL(nltap(c)); } /* also fold in the length of the key */ ADDKEY(inlen); /* now diffuse */ s128_diffuse(c); c->nbuf = 0; } return CRYPT_OK; } /** Make the PRNG ready to read from @param prng The PRNG to make active @return CRYPT_OK if successful */ int sober128_ready(prng_state *prng) { return prng->sober128.set == 1 ? CRYPT_OK : CRYPT_ERROR; } /* XOR pseudo-random bytes into buffer */ #define SROUND(z) STEP(c->R,z); NLFUNC(c,(z+1)); XORWORD(t, out+(z*4)); /** Read from the PRNG @param out Destination @param outlen Length of output @param prng The active PRNG to read from @return Number of octets read */ unsigned long sober128_read(unsigned char *out, unsigned long outlen, prng_state *prng) { struct sober128_prng *c; ulong32 t, tlen; LTC_ARGCHK(out != NULL); LTC_ARGCHK(prng != NULL); #ifdef LTC_VALGRIND zeromem(out, outlen); #endif c = &(prng->sober128); t = 0; tlen = outlen; /* handle any previously buffered bytes */ while (c->nbuf != 0 && outlen != 0) { *out++ ^= c->sbuf & 0xFF; c->sbuf >>= 8; c->nbuf -= 8; --outlen; } #ifndef LTC_SMALL_CODE /* do lots at a time, if there's enough to do */ while (outlen >= 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); out += 4*N; outlen -= 4*N; } #endif /* do small or odd size buffers the slow way */ while (4 <= outlen) { cycle(c->R); t = nltap(c); XORWORD(t, out); out += 4; outlen -= 4; } /* handle any trailing bytes */ if (outlen != 0) { cycle(c->R); c->sbuf = nltap(c); c->nbuf = 32; while (c->nbuf != 0 && outlen != 0) { *out++ ^= c->sbuf & 0xFF; c->sbuf >>= 8; c->nbuf -= 8; --outlen; } } return tlen; } /** Terminate the PRNG @param prng The PRNG to terminate @return CRYPT_OK if successful */ int sober128_done(prng_state *prng) { LTC_ARGCHK(prng != NULL); return CRYPT_OK; } /** Export the PRNG state @param out [out] Destination @param outlen [in/out] Max size and resulting size of the state @param prng The PRNG to export @return CRYPT_OK if successful */ int sober128_export(unsigned char *out, unsigned long *outlen, prng_state *prng) { LTC_ARGCHK(outlen != NULL); LTC_ARGCHK(out != NULL); LTC_ARGCHK(prng != NULL); if (*outlen < 64) { *outlen = 64; return CRYPT_BUFFER_OVERFLOW; } if (sober128_read(out, 64, prng) != 64) { return CRYPT_ERROR_READPRNG; } *outlen = 64; return CRYPT_OK; } /** Import a PRNG state @param in The PRNG state @param inlen Size of the state @param prng The PRNG to import @return CRYPT_OK if successful */ int sober128_import(const unsigned char *in, unsigned long inlen, prng_state *prng) { int err; LTC_ARGCHK(in != NULL); LTC_ARGCHK(prng != NULL); if (inlen != 64) { return CRYPT_INVALID_ARG; } if ((err = sober128_start(prng)) != CRYPT_OK) { return err; } if ((err = sober128_add_entropy(in, 64, prng)) != CRYPT_OK) { return err; } return sober128_ready(prng); } /** PRNG self-test @return CRYPT_OK if successful, CRYPT_NOP if self-testing has been disabled */ int sober128_test(void) { #ifndef LTC_TEST return CRYPT_NOP; #else static const struct { int keylen, ivlen, len; unsigned char key[16], iv[4], out[20]; } tests[] = { { 16, 4, 20, /* key */ { 0x74, 0x65, 0x73, 0x74, 0x20, 0x6b, 0x65, 0x79, 0x20, 0x31, 0x32, 0x38, 0x62, 0x69, 0x74, 0x73 }, /* IV */ { 0x00, 0x00, 0x00, 0x00 }, /* expected output */ { 0x43, 0x50, 0x0c, 0xcf, 0x89, 0x91, 0x9f, 0x1d, 0xaa, 0x37, 0x74, 0x95, 0xf4, 0xb4, 0x58, 0xc2, 0x40, 0x37, 0x8b, 0xbb } } }; prng_state prng; unsigned char dst[20]; int err, x; for (x = 0; x < (int)(sizeof(tests)/sizeof(tests[0])); x++) { if ((err = sober128_start(&prng)) != CRYPT_OK) { return err; } if ((err = sober128_add_entropy(tests[x].key, tests[x].keylen, &prng)) != CRYPT_OK) { return err; } /* add IV */ if ((err = sober128_add_entropy(tests[x].iv, tests[x].ivlen, &prng)) != CRYPT_OK) { return err; } /* ready up */ if ((err = sober128_ready(&prng)) != CRYPT_OK) { return err; } XMEMSET(dst, 0, tests[x].len); if (sober128_read(dst, tests[x].len, &prng) != (unsigned long)tests[x].len) { return CRYPT_ERROR_READPRNG; } sober128_done(&prng); if (XMEMCMP(dst, tests[x].out, tests[x].len)) { #if 0 printf("\n\nSOBER128 failed, I got:\n"); for (y = 0; y < tests[x].len; y++) printf("%02x ", dst[y]); printf("\n"); #endif return CRYPT_FAIL_TESTVECTOR; } } return CRYPT_OK; #endif } #endif /* $Source: /cvs/libtom/libtomcrypt/src/prngs/sober128.c,v $ */ /* $Revision: 1.8 $ */ /* $Date: 2006/11/05 00:11:36 $ */