+++ /dev/null
-/* Modified for SILC. -Pekka */
-
-/* This is an independent implementation of the encryption algorithm: */
-/* */
-/* Twofish by Bruce Schneier and colleagues */
-/* */
-/* which is a candidate algorithm in the Advanced Encryption Standard */
-/* programme of the US National Institute of Standards and Technology. */
-/* */
-/* Copyright in this implementation is held by Dr B R Gladman but I */
-/* hereby give permission for its free direct or derivative use subject */
-/* to acknowledgment of its origin and compliance with any conditions */
-/* that the originators of t he algorithm place on its exploitation. */
-/* */
-/* My thanks to Doug Whiting and Niels Ferguson for comments that led */
-/* to improvements in this implementation. */
-/* */
-/* Dr Brian Gladman (gladman@seven77.demon.co.uk) 14th January 1999 */
-
-/* Timing data for Twofish (twofish.c)
-
-128 bit key:
-Key Setup: 8414 cycles
-Encrypt: 376 cycles = 68.1 mbits/sec
-Decrypt: 374 cycles = 68.4 mbits/sec
-Mean: 375 cycles = 68.3 mbits/sec
-
-192 bit key:
-Key Setup: 11628 cycles
-Encrypt: 376 cycles = 68.1 mbits/sec
-Decrypt: 374 cycles = 68.4 mbits/sec
-Mean: 375 cycles = 68.3 mbits/sec
-
-256 bit key:
-Key Setup: 15457 cycles
-Encrypt: 381 cycles = 67.2 mbits/sec
-Decrypt: 374 cycles = 68.4 mbits/sec
-Mean: 378 cycles = 67.8 mbits/sec
-
-*/
-
-#include "silc.h"
-#include "twofish_internal.h"
-#include "twofish.h"
-
-/*
- * SILC Crypto API for Twofish
- */
-
-/* Sets the key for the cipher. */
-
-SILC_CIPHER_API_SET_KEY(twofish)
-{
- SilcUInt32 k[8];
-
- SILC_GET_WORD_KEY(key, k, keylen);
- twofish_set_key((TwofishContext *)context, k, keylen);
-
- return TRUE;
-}
-
-/* Sets IV for the cipher. */
-
-SILC_CIPHER_API_SET_IV(twofish)
-{
- TwofishContext *twofish = context;
-
- switch (cipher->mode) {
-
- case SILC_CIPHER_MODE_CTR:
- /* Starts new block. */
- twofish->padlen = 0;
- break;
-
- case SILC_CIPHER_MODE_CFB:
- /* Starts new block. */
- twofish->padlen = 16;
- break;
-
- default:
- break;
- }
-}
-
-/* Returns the size of the cipher context. */
-
-SILC_CIPHER_API_CONTEXT_LEN(twofish)
-{
- return sizeof(TwofishContext);
-}
-
-/* Encrypts with the cipher. Source and destination buffers maybe one
- and same. */
-
-SILC_CIPHER_API_ENCRYPT(twofish)
-{
- TwofishContext *twofish = context;
- SilcUInt32 tmp[4], ctr[4];
- int i;
-
- switch (cipher->mode) {
-
- case SILC_CIPHER_MODE_CBC:
- SILC_CBC_ENC_LSB_128_32(len, iv, tmp, src, dst, i,
- twofish_encrypt(twofish, tmp, tmp));
- break;
-
- case SILC_CIPHER_MODE_CTR:
- SILC_CTR_LSB_128_32(iv, ctr, tmp, twofish->padlen, src, dst,
- twofish_encrypt(twofish, tmp, tmp));
- break;
-
- case SILC_CIPHER_MODE_CFB:
- SILC_CFB_ENC_LSB_128_32(iv, tmp, twofish->padlen, src, dst,
- twofish_encrypt(twofish, tmp, tmp));
- break;
-
- default:
- return FALSE;
- }
-
- return TRUE;
-}
-
-/* Decrypts with the cipher. Source and destination buffers maybe one
- and same. */
-
-SILC_CIPHER_API_DECRYPT(twofish)
-{
- TwofishContext *twofish = context;
- SilcUInt32 tmp[4], tmp2[4], tiv[4];
- int i;
-
- switch (cipher->mode) {
-
- case SILC_CIPHER_MODE_CBC:
- SILC_CBC_DEC_LSB_128_32(len, iv, tiv, tmp, tmp2, src, dst, i,
- twofish_decrypt(twofish, tmp, tmp2));
-
- case SILC_CIPHER_MODE_CTR:
- return silc_twofish_encrypt(cipher, context, src, dst, len, iv);
- break;
-
- case SILC_CIPHER_MODE_CFB:
- SILC_CFB_DEC_LSB_128_32(iv, tmp, twofish->padlen, src, dst,
- twofish_encrypt(twofish, tmp, tmp));
- break;
-
- default:
- return FALSE;
- }
-
- return TRUE;
-}
-
-#if 0
-#define Q_TABLES
-#define M_TABLE
-#define MK_TABLE
-#define ONE_STEP
-#endif
-
-/* finite field arithmetic for GF(2**8) with the modular */
-/* polynomial x^8 + x^6 + x^5 + x^3 + 1 (0x169) */
-
-#define G_M 0x0169
-
-u1byte tab_5b[4] = { 0, G_M >> 2, G_M >> 1, (G_M >> 1) ^ (G_M >> 2) };
-u1byte tab_ef[4] = { 0, (G_M >> 1) ^ (G_M >> 2), G_M >> 1, G_M >> 2 };
-
-#define ffm_01(x) (x)
-#define ffm_5b(x) ((x) ^ ((x) >> 2) ^ tab_5b[(x) & 3])
-#define ffm_ef(x) ((x) ^ ((x) >> 1) ^ ((x) >> 2) ^ tab_ef[(x) & 3])
-
-u1byte ror4[16] = { 0, 8, 1, 9, 2, 10, 3, 11, 4, 12, 5, 13, 6, 14, 7, 15 };
-u1byte ashx[16] = { 0, 9, 2, 11, 4, 13, 6, 15, 8, 1, 10, 3, 12, 5, 14, 7 };
-
-u1byte qt0[2][16] =
-{ { 8, 1, 7, 13, 6, 15, 3, 2, 0, 11, 5, 9, 14, 12, 10, 4 },
- { 2, 8, 11, 13, 15, 7, 6, 14, 3, 1, 9, 4, 0, 10, 12, 5 }
-};
-
-u1byte qt1[2][16] =
-{ { 14, 12, 11, 8, 1, 2, 3, 5, 15, 4, 10, 6, 7, 0, 9, 13 },
- { 1, 14, 2, 11, 4, 12, 3, 7, 6, 13, 10, 5, 15, 9, 0, 8 }
-};
-
-u1byte qt2[2][16] =
-{ { 11, 10, 5, 14, 6, 13, 9, 0, 12, 8, 15, 3, 2, 4, 7, 1 },
- { 4, 12, 7, 5, 1, 6, 9, 10, 0, 14, 13, 8, 2, 11, 3, 15 }
-};
-
-u1byte qt3[2][16] =
-{ { 13, 7, 15, 4, 1, 2, 6, 14, 9, 11, 3, 0, 8, 5, 12, 10 },
- { 11, 9, 5, 1, 12, 3, 13, 14, 6, 4, 7, 15, 2, 0, 8, 10 }
-};
-
-u1byte qp(const u4byte n, const u1byte x)
-{ u1byte a0, a1, a2, a3, a4, b0, b1, b2, b3, b4;
-
- a0 = x >> 4; b0 = x & 15;
- a1 = a0 ^ b0; b1 = ror4[b0] ^ ashx[a0];
- a2 = qt0[n][a1]; b2 = qt1[n][b1];
- a3 = a2 ^ b2; b3 = ror4[b2] ^ ashx[a2];
- a4 = qt2[n][a3]; b4 = qt3[n][b3];
- return (b4 << 4) | a4;
-}
-
-#ifdef Q_TABLES
-
-u4byte qt_gen = 0;
-u1byte q_tab[2][256];
-
-#define q(n,x) q_tab[n][x]
-
-void gen_qtab(void)
-{ u4byte i;
-
- for(i = 0; i < 256; ++i)
- {
- q(0,i) = qp(0, (u1byte)i);
- q(1,i) = qp(1, (u1byte)i);
- }
-}
-
-#else
-
-#define q(n,x) qp(n, x)
-
-#endif
-
-#ifdef M_TABLE
-
-u4byte mt_gen = 0;
-u4byte m_tab[4][256];
-
-void gen_mtab(void)
-{ u4byte i, f01, f5b, fef;
-
- for(i = 0; i < 256; ++i)
- {
- f01 = q(1,i); f5b = ffm_5b(f01); fef = ffm_ef(f01);
- m_tab[0][i] = f01 + (f5b << 8) + (fef << 16) + (fef << 24);
- m_tab[2][i] = f5b + (fef << 8) + (f01 << 16) + (fef << 24);
-
- f01 = q(0,i); f5b = ffm_5b(f01); fef = ffm_ef(f01);
- m_tab[1][i] = fef + (fef << 8) + (f5b << 16) + (f01 << 24);
- m_tab[3][i] = f5b + (f01 << 8) + (fef << 16) + (f5b << 24);
- }
-}
-
-#define mds(n,x) m_tab[n][x]
-
-#else
-
-#define fm_00 ffm_01
-#define fm_10 ffm_5b
-#define fm_20 ffm_ef
-#define fm_30 ffm_ef
-#define q_0(x) q(1,x)
-
-#define fm_01 ffm_ef
-#define fm_11 ffm_ef
-#define fm_21 ffm_5b
-#define fm_31 ffm_01
-#define q_1(x) q(0,x)
-
-#define fm_02 ffm_5b
-#define fm_12 ffm_ef
-#define fm_22 ffm_01
-#define fm_32 ffm_ef
-#define q_2(x) q(1,x)
-
-#define fm_03 ffm_5b
-#define fm_13 ffm_01
-#define fm_23 ffm_ef
-#define fm_33 ffm_5b
-#define q_3(x) q(0,x)
-
-#define f_0(n,x) ((u4byte)fm_0##n(x))
-#define f_1(n,x) ((u4byte)fm_1##n(x) << 8)
-#define f_2(n,x) ((u4byte)fm_2##n(x) << 16)
-#define f_3(n,x) ((u4byte)fm_3##n(x) << 24)
-
-#define mds(n,x) f_0(n,q_##n(x)) ^ f_1(n,q_##n(x)) ^ f_2(n,q_##n(x)) ^ f_3(n,q_##n(x))
-
-#endif
-
-u4byte h_fun(TwofishContext *ctx, const u4byte x, const u4byte key[])
-{ u4byte b0, b1, b2, b3;
-
-#ifndef M_TABLE
- u4byte m5b_b0, m5b_b1, m5b_b2, m5b_b3;
- u4byte mef_b0, mef_b1, mef_b2, mef_b3;
-#endif
-
- b0 = byte(x, 0); b1 = byte(x, 1); b2 = byte(x, 2); b3 = byte(x, 3);
-
- switch(ctx->k_len)
- {
- case 4: b0 = q(1, b0) ^ byte(key[3],0);
- b1 = q(0, b1) ^ byte(key[3],1);
- b2 = q(0, b2) ^ byte(key[3],2);
- b3 = q(1, b3) ^ byte(key[3],3);
- case 3: b0 = q(1, b0) ^ byte(key[2],0);
- b1 = q(1, b1) ^ byte(key[2],1);
- b2 = q(0, b2) ^ byte(key[2],2);
- b3 = q(0, b3) ^ byte(key[2],3);
- case 2: b0 = q(0,q(0,b0) ^ byte(key[1],0)) ^ byte(key[0],0);
- b1 = q(0,q(1,b1) ^ byte(key[1],1)) ^ byte(key[0],1);
- b2 = q(1,q(0,b2) ^ byte(key[1],2)) ^ byte(key[0],2);
- b3 = q(1,q(1,b3) ^ byte(key[1],3)) ^ byte(key[0],3);
- }
-#ifdef M_TABLE
-
- return mds(0, b0) ^ mds(1, b1) ^ mds(2, b2) ^ mds(3, b3);
-
-#else
-
- b0 = q(1, b0); b1 = q(0, b1); b2 = q(1, b2); b3 = q(0, b3);
- m5b_b0 = ffm_5b(b0); m5b_b1 = ffm_5b(b1); m5b_b2 = ffm_5b(b2); m5b_b3 = ffm_5b(b3);
- mef_b0 = ffm_ef(b0); mef_b1 = ffm_ef(b1); mef_b2 = ffm_ef(b2); mef_b3 = ffm_ef(b3);
- b0 ^= mef_b1 ^ m5b_b2 ^ m5b_b3; b3 ^= m5b_b0 ^ mef_b1 ^ mef_b2;
- b2 ^= mef_b0 ^ m5b_b1 ^ mef_b3; b1 ^= mef_b0 ^ mef_b2 ^ m5b_b3;
-
- return b0 | (b3 << 8) | (b2 << 16) | (b1 << 24);
-
-#endif
-}
-
-#ifdef MK_TABLE
-
-#ifdef ONE_STEP
-u4byte mk_tab[4][256];
-#else
-u1byte sb[4][256];
-#endif
-
-#define q20(x) q(0,q(0,x) ^ byte(key[1],0)) ^ byte(key[0],0)
-#define q21(x) q(0,q(1,x) ^ byte(key[1],1)) ^ byte(key[0],1)
-#define q22(x) q(1,q(0,x) ^ byte(key[1],2)) ^ byte(key[0],2)
-#define q23(x) q(1,q(1,x) ^ byte(key[1],3)) ^ byte(key[0],3)
-
-#define q30(x) q(0,q(0,q(1, x) ^ byte(key[2],0)) ^ byte(key[1],0)) ^ byte(key[0],0)
-#define q31(x) q(0,q(1,q(1, x) ^ byte(key[2],1)) ^ byte(key[1],1)) ^ byte(key[0],1)
-#define q32(x) q(1,q(0,q(0, x) ^ byte(key[2],2)) ^ byte(key[1],2)) ^ byte(key[0],2)
-#define q33(x) q(1,q(1,q(0, x) ^ byte(key[2],3)) ^ byte(key[1],3)) ^ byte(key[0],3)
-
-#define q40(x) q(0,q(0,q(1, q(1, x) ^ byte(key[3],0)) ^ byte(key[2],0)) ^ byte(key[1],0)) ^ byte(key[0],0)
-#define q41(x) q(0,q(1,q(1, q(0, x) ^ byte(key[3],1)) ^ byte(key[2],1)) ^ byte(key[1],1)) ^ byte(key[0],1)
-#define q42(x) q(1,q(0,q(0, q(0, x) ^ byte(key[3],2)) ^ byte(key[2],2)) ^ byte(key[1],2)) ^ byte(key[0],2)
-#define q43(x) q(1,q(1,q(0, q(1, x) ^ byte(key[3],3)) ^ byte(key[2],3)) ^ byte(key[1],3)) ^ byte(key[0],3)
-
-void gen_mk_tab(TwofishContext *ctx, u4byte key[])
-{ u4byte i;
- u1byte by;
-
- switch(ctx->k_len)
- {
- case 2: for(i = 0; i < 256; ++i)
- {
- by = (u1byte)i;
-#ifdef ONE_STEP
- mk_tab[0][i] = mds(0, q20(by)); mk_tab[1][i] = mds(1, q21(by));
- mk_tab[2][i] = mds(2, q22(by)); mk_tab[3][i] = mds(3, q23(by));
-#else
- sb[0][i] = q20(by); sb[1][i] = q21(by);
- sb[2][i] = q22(by); sb[3][i] = q23(by);
-#endif
- }
- break;
-
- case 3: for(i = 0; i < 256; ++i)
- {
- by = (u1byte)i;
-#ifdef ONE_STEP
- mk_tab[0][i] = mds(0, q30(by)); mk_tab[1][i] = mds(1, q31(by));
- mk_tab[2][i] = mds(2, q32(by)); mk_tab[3][i] = mds(3, q33(by));
-#else
- sb[0][i] = q30(by); sb[1][i] = q31(by);
- sb[2][i] = q32(by); sb[3][i] = q33(by);
-#endif
- }
- break;
-
- case 4: for(i = 0; i < 256; ++i)
- {
- by = (u1byte)i;
-#ifdef ONE_STEP
- mk_tab[0][i] = mds(0, q40(by)); mk_tab[1][i] = mds(1, q41(by));
- mk_tab[2][i] = mds(2, q42(by)); mk_tab[3][i] = mds(3, q43(by));
-#else
- sb[0][i] = q40(by); sb[1][i] = q41(by);
- sb[2][i] = q42(by); sb[3][i] = q43(by);
-#endif
- }
- }
-}
-
-# ifdef ONE_STEP
-# define g0_fun(x) ( mk_tab[0][byte(x,0)] ^ mk_tab[1][byte(x,1)] \
- ^ mk_tab[2][byte(x,2)] ^ mk_tab[3][byte(x,3)] )
-# define g1_fun(x) ( mk_tab[0][byte(x,3)] ^ mk_tab[1][byte(x,0)] \
- ^ mk_tab[2][byte(x,1)] ^ mk_tab[3][byte(x,2)] )
-# else
-# define g0_fun(x) ( mds(0, sb[0][byte(x,0)]) ^ mds(1, sb[1][byte(x,1)]) \
- ^ mds(2, sb[2][byte(x,2)]) ^ mds(3, sb[3][byte(x,3)]) )
-# define g1_fun(x) ( mds(0, sb[0][byte(x,3)]) ^ mds(1, sb[1][byte(x,0)]) \
- ^ mds(2, sb[2][byte(x,1)]) ^ mds(3, sb[3][byte(x,2)]) )
-# endif
-
-#else
-
-#define g0_fun(x) h_fun(ctx,x,s_key)
-#define g1_fun(x) h_fun(ctx,rotl(x,8),s_key)
-
-#endif
-
-/* The (12,8) Reed Soloman code has the generator polynomial
-
- g(x) = x^4 + (a + 1/a) * x^3 + a * x^2 + (a + 1/a) * x + 1
-
-where the coefficients are in the finite field GF(2^8) with a
-modular polynomial a^8 + a^6 + a^3 + a^2 + 1. To generate the
-remainder we have to start with a 12th order polynomial with our
-eight input bytes as the coefficients of the 4th to 11th terms.
-That is:
-
- m[7] * x^11 + m[6] * x^10 ... + m[0] * x^4 + 0 * x^3 +... + 0
-
-We then multiply the generator polynomial by m[7] * x^7 and subtract
-it - xor in GF(2^8) - from the above to eliminate the x^7 term (the
-artihmetic on the coefficients is done in GF(2^8). We then multiply
-the generator polynomial by x^6 * coeff(x^10) and use this to remove
-the x^10 term. We carry on in this way until the x^4 term is removed
-so that we are left with:
-
- r[3] * x^3 + r[2] * x^2 + r[1] 8 x^1 + r[0]
-
-which give the resulting 4 bytes of the remainder. This is equivalent
-to the matrix multiplication in the Twofish description but much faster
-to implement.
-
-*/
-
-#define G_MOD 0x0000014d
-
-u4byte mds_rem(u4byte p0, u4byte p1)
-{ u4byte i, t, u;
-
- for(i = 0; i < 8; ++i)
- {
- t = p1 >> 24; /* get most significant coefficient */
-
- p1 = (p1 << 8) | (p0 >> 24); p0 <<= 8; /* shift others up */
-
- /* multiply t by a (the primitive element - i.e. left shift) */
-
- u = (t << 1);
-
- if(t & 0x80) /* subtract modular polynomial on overflow */
-
- u ^= G_MOD;
-
- p1 ^= t ^ (u << 16); /* remove t * (a * x^2 + 1) */
-
- u ^= (t >> 1); /* form u = a * t + t / a = t * (a + 1 / a); */
-
- if(t & 0x01) /* add the modular polynomial on underflow */
-
- u ^= G_MOD >> 1;
-
- p1 ^= (u << 24) | (u << 8); /* remove t * (a + 1/a) * (x^3 + x) */
- }
-
- return p1;
-}
-
-/* initialise the key schedule from the user supplied key */
-
-u4byte *twofish_set_key(TwofishContext *ctx,
- const u4byte in_key[], const u4byte key_len)
-{
- u4byte i, a, b, me_key[4], mo_key[4];
- u4byte *l_key = ctx->l_key;
- u4byte *s_key = ctx->s_key;
-
-#ifdef Q_TABLES
- if(!qt_gen)
- {
- gen_qtab(); qt_gen = 1;
- }
-#endif
-
-#ifdef M_TABLE
- if(!mt_gen)
- {
- gen_mtab(); mt_gen = 1;
- }
-#endif
-
- ctx->k_len = ctx->k_len = key_len / 64; /* 2, 3 or 4 */
-
- for(i = 0; i < ctx->k_len; ++i)
- {
- a = in_key[i + i]; me_key[i] = a;
- b = in_key[i + i + 1]; mo_key[i] = b;
- s_key[ctx->k_len - i - 1] = mds_rem(a, b);
- }
-
- for(i = 0; i < 40; i += 2)
- {
- a = 0x01010101 * i; b = a + 0x01010101;
- a = h_fun(ctx,a, me_key);
- b = rotl(h_fun(ctx,b, mo_key), 8);
- l_key[i] = a + b;
- l_key[i + 1] = rotl(a + 2 * b, 9);
- }
-
-#ifdef MK_TABLE
- gen_mk_tab(ctx,s_key);
-#endif
-
- return l_key;
-}
-
-/* encrypt a block of text */
-
-#define f_rnd(i) \
- t1 = g1_fun(blk[1]); t0 = g0_fun(blk[0]); \
- blk[2] = rotr(blk[2] ^ (t0 + t1 + l_key[4 * (i) + 8]), 1); \
- blk[3] = rotl(blk[3], 1) ^ (t0 + 2 * t1 + l_key[4 * (i) + 9]); \
- t1 = g1_fun(blk[3]); t0 = g0_fun(blk[2]); \
- blk[0] = rotr(blk[0] ^ (t0 + t1 + l_key[4 * (i) + 10]), 1); \
- blk[1] = rotl(blk[1], 1) ^ (t0 + 2 * t1 + l_key[4 * (i) + 11])
-
-void twofish_encrypt(TwofishContext *ctx,
- const u4byte in_blk[4], u4byte out_blk[])
-{
- u4byte t0, t1, blk[4];
- u4byte *l_key = ctx->l_key;
- u4byte *s_key = ctx->s_key;
-
- blk[0] = in_blk[0] ^ l_key[0];
- blk[1] = in_blk[1] ^ l_key[1];
- blk[2] = in_blk[2] ^ l_key[2];
- blk[3] = in_blk[3] ^ l_key[3];
-
- f_rnd(0); f_rnd(1); f_rnd(2); f_rnd(3);
- f_rnd(4); f_rnd(5); f_rnd(6); f_rnd(7);
-
- out_blk[0] = blk[2] ^ l_key[4];
- out_blk[1] = blk[3] ^ l_key[5];
- out_blk[2] = blk[0] ^ l_key[6];
- out_blk[3] = blk[1] ^ l_key[7];
-}
-
-/* decrypt a block of text */
-
-#define i_rnd(i) \
- t1 = g1_fun(blk[1]); t0 = g0_fun(blk[0]); \
- blk[2] = rotl(blk[2], 1) ^ (t0 + t1 + l_key[4 * (i) + 10]); \
- blk[3] = rotr(blk[3] ^ (t0 + 2 * t1 + l_key[4 * (i) + 11]), 1); \
- t1 = g1_fun(blk[3]); t0 = g0_fun(blk[2]); \
- blk[0] = rotl(blk[0], 1) ^ (t0 + t1 + l_key[4 * (i) + 8]); \
- blk[1] = rotr(blk[1] ^ (t0 + 2 * t1 + l_key[4 * (i) + 9]), 1)
-
-void twofish_decrypt(TwofishContext *ctx,
- const u4byte in_blk[4], u4byte out_blk[4])
-{
- u4byte t0, t1, blk[4];
- u4byte *l_key = ctx->l_key;
- u4byte *s_key = ctx->s_key;
-
- blk[0] = in_blk[0] ^ l_key[4];
- blk[1] = in_blk[1] ^ l_key[5];
- blk[2] = in_blk[2] ^ l_key[6];
- blk[3] = in_blk[3] ^ l_key[7];
-
- i_rnd(7); i_rnd(6); i_rnd(5); i_rnd(4);
- i_rnd(3); i_rnd(2); i_rnd(1); i_rnd(0);
-
- out_blk[0] = blk[2] ^ l_key[0];
- out_blk[1] = blk[3] ^ l_key[1];
- out_blk[2] = blk[0] ^ l_key[2];
- out_blk[3] = blk[1] ^ l_key[3];
-}
projects / silc.git / blobdiff