X-Git-Url: https://pd.if.org/git/?a=blobdiff_plain;f=libtomcrypt%2Fsrc%2Fstream%2Fsober128%2Fsober128_stream.c;fp=libtomcrypt%2Fsrc%2Fstream%2Fsober128%2Fsober128_stream.c;h=5c35edac5f5f3a2ea7cad506edc4e53f7692db25;hb=66bc25938679f1d6a1d1200f329093d82a5e99b4;hp=0000000000000000000000000000000000000000;hpb=a52ee0733f420ca20224049260d6fc5cf7d8f621;p=zpackage diff --git a/libtomcrypt/src/stream/sober128/sober128_stream.c b/libtomcrypt/src/stream/sober128/sober128_stream.c new file mode 100644 index 0000000..5c35eda --- /dev/null +++ b/libtomcrypt/src/stream/sober128/sober128_stream.c @@ -0,0 +1,346 @@ +/* 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. + */ +#include "tomcrypt.h" + +/** + @file sober128_stream.c + Implementation of SOBER-128 by Tom St Denis. + Based on s128fast.c reference code supplied by Greg Rose of QUALCOMM. +*/ + +#ifdef LTC_SOBER128 + +#define __LTC_SOBER128TAB_C__ +#include "sober128tab.c" + +/* 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; +} + +static void XORWORD(ulong32 w, const unsigned char *in, unsigned char *out) +{ + ulong32 t; + LOAD32L(t, in); + t ^= w; + STORE32L(t, out); +} + +/* 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(sober128_state *c) +{ + ulong32 t; + NLFUNC(c, 0); + return t; +} + +/* Save the current register state + */ +static void s128_savestate(sober128_state *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_state *c) +{ + int i; + + for (i = 0; i < N; ++i) { + c->R[i] = c->initR[i]; + } +} + +/* Initialise "konst" + */ +static void s128_genkonst(sober128_state *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_state *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); +} + +/** + Initialize an Sober128 context (only the key) + @param c [out] The destination of the Sober128 state + @param key The secret key + @param keylen The length of the secret key (octets) + @return CRYPT_OK if successful +*/ +int sober128_stream_setup(sober128_state *c, const unsigned char *key, unsigned long keylen) +{ + ulong32 i, k; + + LTC_ARGCHK(c != NULL); + LTC_ARGCHK(key != NULL); + LTC_ARGCHK(keylen > 0); + + /* keylen must be multiple of 4 bytes */ + if ((keylen & 3) != 0) { + return CRYPT_INVALID_KEYSIZE; + } + + /* 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; + + for (i = 0; i < keylen; i += 4) { + k = BYTE2WORD((unsigned char *)&key[i]); + ADDKEY(k); + cycle(c->R); + XORNL(nltap(c)); + } + + /* also fold in the length of the key */ + ADDKEY(keylen); + + /* now diffuse */ + s128_diffuse(c); + s128_genkonst(c); + s128_savestate(c); + c->nbuf = 0; + + return CRYPT_OK; +} + +/** + Set IV to the Sober128 state + @param c The Sober12820 state + @param iv The IV data to add + @param ivlen The length of the IV (must be 12) + @return CRYPT_OK on success + */ +int sober128_stream_setiv(sober128_state *c, const unsigned char *iv, unsigned long ivlen) +{ + ulong32 i, k; + + LTC_ARGCHK(c != NULL); + LTC_ARGCHK(iv != NULL); + LTC_ARGCHK(ivlen > 0); + + /* ok we are adding an IV then... */ + s128_reloadstate(c); + + /* ivlen must be multiple of 4 bytes */ + if ((ivlen & 3) != 0) { + return CRYPT_INVALID_KEYSIZE; + } + + for (i = 0; i < ivlen; i += 4) { + k = BYTE2WORD((unsigned char *)&iv[i]); + ADDKEY(k); + cycle(c->R); + XORNL(nltap(c)); + } + + /* also fold in the length of the key */ + ADDKEY(ivlen); + + /* now diffuse */ + s128_diffuse(c); + c->nbuf = 0; + + return CRYPT_OK; +} + +/* XOR pseudo-random bytes into buffer + */ +#define SROUND(z) STEP(c->R,z); NLFUNC(c,(z+1)); XORWORD(t, in+(z*4), out+(z*4)); + +/** + Encrypt (or decrypt) bytes of ciphertext (or plaintext) with Sober128 + @param c The Sober128 state + @param in The plaintext (or ciphertext) + @param inlen The length of the input (octets) + @param out [out] The ciphertext (or plaintext), length inlen + @return CRYPT_OK if successful +*/ +int sober128_stream_crypt(sober128_state *c, const unsigned char *in, unsigned long inlen, unsigned char *out) +{ + ulong32 t; + + if (inlen == 0) return CRYPT_OK; /* nothing to do */ + LTC_ARGCHK(out != NULL); + LTC_ARGCHK(c != NULL); + + /* handle any previously buffered bytes */ + while (c->nbuf != 0 && inlen != 0) { + *out++ = *in++ ^ (unsigned char)(c->sbuf & 0xFF); + c->sbuf >>= 8; + c->nbuf -= 8; + --inlen; + } + +#ifndef LTC_SMALL_CODE + /* do lots at a time, if there's enough to do */ + while (inlen >= 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; + in += 4*N; + inlen -= 4*N; + } +#endif + + /* do small or odd size buffers the slow way */ + while (4 <= inlen) { + cycle(c->R); + t = nltap(c); + XORWORD(t, in, out); + out += 4; + in += 4; + inlen -= 4; + } + + /* handle any trailing bytes */ + if (inlen != 0) { + cycle(c->R); + c->sbuf = nltap(c); + c->nbuf = 32; + while (c->nbuf != 0 && inlen != 0) { + *out++ = *in++ ^ (unsigned char)(c->sbuf & 0xFF); + c->sbuf >>= 8; + c->nbuf -= 8; + --inlen; + } + } + + return CRYPT_OK; +} + +int sober128_stream_keystream(sober128_state *c, unsigned char *out, unsigned long outlen) +{ + if (outlen == 0) return CRYPT_OK; /* nothing to do */ + LTC_ARGCHK(out != NULL); + XMEMSET(out, 0, outlen); + return sober128_stream_crypt(c, out, outlen, out); +} + +/** + Terminate and clear Sober128 state + @param c The Sober128 state + @return CRYPT_OK on success +*/ +int sober128_stream_done(sober128_state *c) +{ + LTC_ARGCHK(c != NULL); + XMEMSET(c, 0, sizeof(sober128_state)); + return CRYPT_OK; +} + +#endif + +/* ref: $Format:%D$ */ +/* git commit: $Format:%H$ */ +/* commit time: $Format:%ai$ */