/* Modified for SILC. -Pekka */ /* This is an independent implementation of the encryption algorithm: */ /* */ /* MARS by a team at IBM, */ /* */ /* 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. The MARS */ /* algorithm is covered by a pending patent application owned by IBM, */ /* who intend to offer a royalty free license under any issued patent */ /* that results from such application if MARS is selected as the AES */ /* algorithm. In the interim, you may evaluate the MARS algorithm for */ /* your personal, lawful, non-profit purposes as an end user. */ /* */ /* The header above modified on June 6th 1999. */ /* Dr Brian Gladman (gladman@seven77.demon.co.uk) 14th January 1999 */ /* Timing data for MARS (mars.c) 128 bit key: Key Setup: 4316 cycles Encrypt: 369 cycles = 69.4 mbits/sec Decrypt: 376 cycles = 68.1 mbits/sec Mean: 373 cycles = 68.7 mbits/sec 192 bit key: Key Setup: 4377 cycles Encrypt: 373 cycles = 68.6 mbits/sec Decrypt: 379 cycles = 67.5 mbits/sec Mean: 376 cycles = 68.1 mbits/sec 256 bit key: Key Setup: 4340 cycles Encrypt: 369 cycles = 69.4 mbits/sec Decrypt: 376 cycles = 68.1 mbits/sec Mean: 373 cycles = 68.7 mbits/sec */ #include "silcincludes.h" #include "mars.h" /* * SILC Crypto API for MARS */ /* Sets the key for cipher MARS. */ SILC_CIPHER_API_SET_KEY(mars) { mars_set_key((MarsContext *)context, (unsigned int *)key, keylen); return TRUE; } /* Sets the string as a new key for the cipher MARS. The string is first hashed and then used as a new key. */ SILC_CIPHER_API_SET_KEY_WITH_STRING(mars) { /* unsigned char key[md5_hash_len]; SilcMarsContext *ctx = (SilcMarsContext *)context; make_md5_hash(string, &key); memcpy(&ctx->key, mars_set_key(&key, keylen), keylen); memset(&key, 'F', sizeoof(key)); */ return TRUE; } /* Returns the size of the MARS cipher context. */ SILC_CIPHER_API_CONTEXT_LEN(mars) { return sizeof(MarsContext); } /* Encrypts with MARS cipher in CBC mode. Source and destination buffers maybe one and same. */ SILC_CIPHER_API_ENCRYPT_CBC(mars) { unsigned int *in, *out, *tiv; unsigned int tmp[4]; int i; in = (unsigned int *)src; out = (unsigned int *)dst; tiv = (unsigned int *)iv; tmp[0] = in[0] ^ tiv[0]; tmp[1] = in[1] ^ tiv[1]; tmp[2] = in[2] ^ tiv[2]; tmp[3] = in[3] ^ tiv[3]; mars_encrypt((MarsContext *)context, tmp, out); in += 4; out += 4; for (i = 16; i < len; i += 16) { tmp[0] = in[0] ^ out[0 - 4]; tmp[1] = in[1] ^ out[1 - 4]; tmp[2] = in[2] ^ out[2 - 4]; tmp[3] = in[3] ^ out[3 - 4]; mars_encrypt((MarsContext *)context, tmp, out); in += 4; out += 4; } tiv[0] = out[0 - 4]; tiv[1] = out[1 - 4]; tiv[2] = out[2 - 4]; tiv[3] = out[3 - 4]; return TRUE; } /* Decrypts with MARS cipher in CBC mode. Source and destination buffers maybe one and same. */ SILC_CIPHER_API_DECRYPT_CBC(mars) { unsigned int *in, *out, *tiv; unsigned int tmp[4], tmp2[4]; int i; in = (unsigned int *)src; out = (unsigned int *)dst; tiv = (unsigned int *)iv; tmp[0] = in[0]; tmp[1] = in[1]; tmp[2] = in[2]; tmp[3] = in[3]; mars_decrypt((MarsContext *)context, in, out); out[0] ^= tiv[0]; out[1] ^= tiv[1]; out[2] ^= tiv[2]; out[3] ^= tiv[3]; in += 4; out += 4; for (i = 16; i < len; i += 16) { tmp2[0] = tmp[0]; tmp2[1] = tmp[1]; tmp2[2] = tmp[2]; tmp2[3] = tmp[3]; tmp[0] = in[0]; tmp[1] = in[1]; tmp[2] = in[2]; tmp[3] = in[3]; mars_decrypt((MarsContext *)context, in, out); out[0] ^= tmp2[0]; out[1] ^= tmp2[1]; out[2] ^= tmp2[2]; out[3] ^= tmp2[3]; in += 4; out += 4; } tiv[0] = tmp[0]; tiv[1] = tmp[1]; tiv[2] = tmp[2]; tiv[3] = tmp[3]; return TRUE; } static u4byte s_box[] = { 0x09d0c479, 0x28c8ffe0, 0x84aa6c39, 0x9dad7287, /* 0x000 */ 0x7dff9be3, 0xd4268361, 0xc96da1d4, 0x7974cc93, 0x85d0582e, 0x2a4b5705, 0x1ca16a62, 0xc3bd279d, 0x0f1f25e5, 0x5160372f, 0xc695c1fb, 0x4d7ff1e4, 0xae5f6bf4, 0x0d72ee46, 0xff23de8a, 0xb1cf8e83, /* 0x010 */ 0xf14902e2, 0x3e981e42, 0x8bf53eb6, 0x7f4bf8ac, 0x83631f83, 0x25970205, 0x76afe784, 0x3a7931d4, 0x4f846450, 0x5c64c3f6, 0x210a5f18, 0xc6986a26, 0x28f4e826, 0x3a60a81c, 0xd340a664, 0x7ea820c4, /* 0x020 */ 0x526687c5, 0x7eddd12b, 0x32a11d1d, 0x9c9ef086, 0x80f6e831, 0xab6f04ad, 0x56fb9b53, 0x8b2e095c, 0xb68556ae, 0xd2250b0d, 0x294a7721, 0xe21fb253, 0xae136749, 0xe82aae86, 0x93365104, 0x99404a66, /* 0x030 */ 0x78a784dc, 0xb69ba84b, 0x04046793, 0x23db5c1e, 0x46cae1d6, 0x2fe28134, 0x5a223942, 0x1863cd5b, 0xc190c6e3, 0x07dfb846, 0x6eb88816, 0x2d0dcc4a, 0xa4ccae59, 0x3798670d, 0xcbfa9493, 0x4f481d45, /* 0x040 */ 0xeafc8ca8, 0xdb1129d6, 0xb0449e20, 0x0f5407fb, 0x6167d9a8, 0xd1f45763, 0x4daa96c3, 0x3bec5958, 0xababa014, 0xb6ccd201, 0x38d6279f, 0x02682215, 0x8f376cd5, 0x092c237e, 0xbfc56593, 0x32889d2c, /* 0x050 */ 0x854b3e95, 0x05bb9b43, 0x7dcd5dcd, 0xa02e926c, 0xfae527e5, 0x36a1c330, 0x3412e1ae, 0xf257f462, 0x3c4f1d71, 0x30a2e809, 0x68e5f551, 0x9c61ba44, 0x5ded0ab8, 0x75ce09c8, 0x9654f93e, 0x698c0cca, /* 0x060 */ 0x243cb3e4, 0x2b062b97, 0x0f3b8d9e, 0x00e050df, 0xfc5d6166, 0xe35f9288, 0xc079550d, 0x0591aee8, 0x8e531e74, 0x75fe3578, 0x2f6d829a, 0xf60b21ae, 0x95e8eb8d, 0x6699486b, 0x901d7d9b, 0xfd6d6e31, /* 0x070 */ 0x1090acef, 0xe0670dd8, 0xdab2e692, 0xcd6d4365, 0xe5393514, 0x3af345f0, 0x6241fc4d, 0x460da3a3, 0x7bcf3729, 0x8bf1d1e0, 0x14aac070, 0x1587ed55, 0x3afd7d3e, 0xd2f29e01, 0x29a9d1f6, 0xefb10c53, /* 0x080 */ 0xcf3b870f, 0xb414935c, 0x664465ed, 0x024acac7, 0x59a744c1, 0x1d2936a7, 0xdc580aa6, 0xcf574ca8, 0x040a7a10, 0x6cd81807, 0x8a98be4c, 0xaccea063, 0xc33e92b5, 0xd1e0e03d, 0xb322517e, 0x2092bd13, /* 0x090 */ 0x386b2c4a, 0x52e8dd58, 0x58656dfb, 0x50820371, 0x41811896, 0xe337ef7e, 0xd39fb119, 0xc97f0df6, 0x68fea01b, 0xa150a6e5, 0x55258962, 0xeb6ff41b, 0xd7c9cd7a, 0xa619cd9e, 0xbcf09576, 0x2672c073, /* 0x0a0 */ 0xf003fb3c, 0x4ab7a50b, 0x1484126a, 0x487ba9b1, 0xa64fc9c6, 0xf6957d49, 0x38b06a75, 0xdd805fcd, 0x63d094cf, 0xf51c999e, 0x1aa4d343, 0xb8495294, 0xce9f8e99, 0xbffcd770, 0xc7c275cc, 0x378453a7, /* 0x0b0 */ 0x7b21be33, 0x397f41bd, 0x4e94d131, 0x92cc1f98, 0x5915ea51, 0x99f861b7, 0xc9980a88, 0x1d74fd5f, 0xb0a495f8, 0x614deed0, 0xb5778eea, 0x5941792d, 0xfa90c1f8, 0x33f824b4, 0xc4965372, 0x3ff6d550, /* 0x0c0 */ 0x4ca5fec0, 0x8630e964, 0x5b3fbbd6, 0x7da26a48, 0xb203231a, 0x04297514, 0x2d639306, 0x2eb13149, 0x16a45272, 0x532459a0, 0x8e5f4872, 0xf966c7d9, 0x07128dc0, 0x0d44db62, 0xafc8d52d, 0x06316131, /* 0x0d0 */ 0xd838e7ce, 0x1bc41d00, 0x3a2e8c0f, 0xea83837e, 0xb984737d, 0x13ba4891, 0xc4f8b949, 0xa6d6acb3, 0xa215cdce, 0x8359838b, 0x6bd1aa31, 0xf579dd52, 0x21b93f93, 0xf5176781, 0x187dfdde, 0xe94aeb76, /* 0x0e0 */ 0x2b38fd54, 0x431de1da, 0xab394825, 0x9ad3048f, 0xdfea32aa, 0x659473e3, 0x623f7863, 0xf3346c59, 0xab3ab685, 0x3346a90b, 0x6b56443e, 0xc6de01f8, 0x8d421fc0, 0x9b0ed10c, 0x88f1a1e9, 0x54c1f029, /* 0x0f0 */ 0x7dead57b, 0x8d7ba426, 0x4cf5178a, 0x551a7cca, 0x1a9a5f08, 0xfcd651b9, 0x25605182, 0xe11fc6c3, 0xb6fd9676, 0x337b3027, 0xb7c8eb14, 0x9e5fd030, 0x6b57e354, 0xad913cf7, 0x7e16688d, 0x58872a69, /* 0x100 */ 0x2c2fc7df, 0xe389ccc6, 0x30738df1, 0x0824a734, 0xe1797a8b, 0xa4a8d57b, 0x5b5d193b, 0xc8a8309b, 0x73f9a978, 0x73398d32, 0x0f59573e, 0xe9df2b03, 0xe8a5b6c8, 0x848d0704, 0x98df93c2, 0x720a1dc3, /* 0x110 */ 0x684f259a, 0x943ba848, 0xa6370152, 0x863b5ea3, 0xd17b978b, 0x6d9b58ef, 0x0a700dd4, 0xa73d36bf, 0x8e6a0829, 0x8695bc14, 0xe35b3447, 0x933ac568, 0x8894b022, 0x2f511c27, 0xddfbcc3c, 0x006662b6, /* 0x120 */ 0x117c83fe, 0x4e12b414, 0xc2bca766, 0x3a2fec10, 0xf4562420, 0x55792e2a, 0x46f5d857, 0xceda25ce, 0xc3601d3b, 0x6c00ab46, 0xefac9c28, 0xb3c35047, 0x611dfee3, 0x257c3207, 0xfdd58482, 0x3b14d84f, /* 0x130 */ 0x23becb64, 0xa075f3a3, 0x088f8ead, 0x07adf158, 0x7796943c, 0xfacabf3d, 0xc09730cd, 0xf7679969, 0xda44e9ed, 0x2c854c12, 0x35935fa3, 0x2f057d9f, 0x690624f8, 0x1cb0bafd, 0x7b0dbdc6, 0x810f23bb, /* 0x140 */ 0xfa929a1a, 0x6d969a17, 0x6742979b, 0x74ac7d05, 0x010e65c4, 0x86a3d963, 0xf907b5a0, 0xd0042bd3, 0x158d7d03, 0x287a8255, 0xbba8366f, 0x096edc33, 0x21916a7b, 0x77b56b86, 0x951622f9, 0xa6c5e650, /* 0x150 */ 0x8cea17d1, 0xcd8c62bc, 0xa3d63433, 0x358a68fd, 0x0f9b9d3c, 0xd6aa295b, 0xfe33384a, 0xc000738e, 0xcd67eb2f, 0xe2eb6dc2, 0x97338b02, 0x06c9f246, 0x419cf1ad, 0x2b83c045, 0x3723f18a, 0xcb5b3089, /* 0x160 */ 0x160bead7, 0x5d494656, 0x35f8a74b, 0x1e4e6c9e, 0x000399bd, 0x67466880, 0xb4174831, 0xacf423b2, 0xca815ab3, 0x5a6395e7, 0x302a67c5, 0x8bdb446b, 0x108f8fa4, 0x10223eda, 0x92b8b48b, 0x7f38d0ee, /* 0x170 */ 0xab2701d4, 0x0262d415, 0xaf224a30, 0xb3d88aba, 0xf8b2c3af, 0xdaf7ef70, 0xcc97d3b7, 0xe9614b6c, 0x2baebff4, 0x70f687cf, 0x386c9156, 0xce092ee5, 0x01e87da6, 0x6ce91e6a, 0xbb7bcc84, 0xc7922c20, /* 0x180 */ 0x9d3b71fd, 0x060e41c6, 0xd7590f15, 0x4e03bb47, 0x183c198e, 0x63eeb240, 0x2ddbf49a, 0x6d5cba54, 0x923750af, 0xf9e14236, 0x7838162b, 0x59726c72, 0x81b66760, 0xbb2926c1, 0x48a0ce0d, 0xa6c0496d, /* 0x190 */ 0xad43507b, 0x718d496a, 0x9df057af, 0x44b1bde6, 0x054356dc, 0xde7ced35, 0xd51a138b, 0x62088cc9, 0x35830311, 0xc96efca2, 0x686f86ec, 0x8e77cb68, 0x63e1d6b8, 0xc80f9778, 0x79c491fd, 0x1b4c67f2, /* 0x1a0 */ 0x72698d7d, 0x5e368c31, 0xf7d95e2e, 0xa1d3493f, 0xdcd9433e, 0x896f1552, 0x4bc4ca7a, 0xa6d1baf4, 0xa5a96dcc, 0x0bef8b46, 0xa169fda7, 0x74df40b7, 0x4e208804, 0x9a756607, 0x038e87c8, 0x20211e44, /* 0x1b0 */ 0x8b7ad4bf, 0xc6403f35, 0x1848e36d, 0x80bdb038, 0x1e62891c, 0x643d2107, 0xbf04d6f8, 0x21092c8c, 0xf644f389, 0x0778404e, 0x7b78adb8, 0xa2c52d53, 0x42157abe, 0xa2253e2e, 0x7bf3f4ae, 0x80f594f9, /* 0x1c0 */ 0x953194e7, 0x77eb92ed, 0xb3816930, 0xda8d9336, 0xbf447469, 0xf26d9483, 0xee6faed5, 0x71371235, 0xde425f73, 0xb4e59f43, 0x7dbe2d4e, 0x2d37b185, 0x49dc9a63, 0x98c39d98, 0x1301c9a2, 0x389b1bbf, /* 0x1d0 */ 0x0c18588d, 0xa421c1ba, 0x7aa3865c, 0x71e08558, 0x3c5cfcaa, 0x7d239ca4, 0x0297d9dd, 0xd7dc2830, 0x4b37802b, 0x7428ab54, 0xaeee0347, 0x4b3fbb85, 0x692f2f08, 0x134e578e, 0x36d9e0bf, 0xae8b5fcf, /* 0x1e0 */ 0xedb93ecf, 0x2b27248e, 0x170eb1ef, 0x7dc57fd6, 0x1e760f16, 0xb1136601, 0x864e1b9b, 0xd7ea7319, 0x3ab871bd, 0xcfa4d76f, 0xe31bd782, 0x0dbeb469, 0xabb96061, 0x5370f85d, 0xffb07e37, 0xda30d0fb, /* 0x1f0 */ 0xebc977b6, 0x0b98b40f, 0x3a4d0fe6, 0xdf4fc26b, 0x159cf22a, 0xc298d6e2, 0x2b78ef6a, 0x61a94ac0, 0xab561187, 0x14eea0f0, 0xdf0d4164, 0x19af70ee }; static u4byte vk[47] = { 0x09d0c479, 0x28c8ffe0, 0x84aa6c39, 0x9dad7287, 0x7dff9be3, 0xd4268361, 0xc96da1d4 }; #define f_mix(a,b,c,d) \ r = rotr(a, 8); \ b ^= s_box[a & 255]; \ b += s_box[(r & 255) + 256]; \ r = rotr(a, 16); \ a = rotr(a, 24); \ c += s_box[r & 255]; \ d ^= s_box[(a & 255) + 256] #define b_mix(a,b,c,d) \ r = rotl(a, 8); \ b ^= s_box[(a & 255) + 256]; \ c -= s_box[r & 255]; \ r = rotl(a, 16); \ a = rotl(a, 24); \ d -= s_box[(r & 255) + 256]; \ d ^= s_box[a & 255] #define f_ktr(a,b,c,d,i) \ m = a + l_key[i]; \ a = rotl(a, 13); \ r = a * l_key[i + 1]; \ l = s_box[m & 511]; \ r = rotl(r, 5); \ c += rotl(m, r); \ l ^= r; \ r = rotl(r, 5); \ l ^= r; \ d ^= r; \ b += rotl(l, r) #define r_ktr(a,b,c,d,i) \ r = a * l_key[i + 1]; \ a = rotr(a, 13); \ m = a + l_key[i]; \ l = s_box[m & 511]; \ r = rotl(r, 5); \ l ^= r; \ c -= rotl(m, r); \ r = rotl(r, 5); \ l ^= r; \ d ^= r; \ b -= rotl(l, r) /* For a 32 bit word (x) generate a mask (m) such that a bit in */ /* m is set to 1 if and only if the corresponding bit in x is: */ /* */ /* 1. in a sequence of 10 or more adjacent '0' bits */ /* 2. in a sequence of 10 or more adjacent '1' bits */ /* 3. but is not either endpoint of such a sequence unless such */ /* an endpoint is at the top bit (bit 31) of a word and is */ /* in a sequence of '0' bits. */ /* */ /* The only situation in which a sequence endpoint is included */ /* in the mask is hence when the endpoint is at bit 31 and is */ /* the endpoint of a sequence of '0' bits. My thanks go to Shai */ /* Halevi of IBM for the neat trick (which I missed) of finding */ /* the '0' and '1' sequences at the same time. */ u4byte gen_mask(u4byte x) { u4byte m; /* if m{bn} stands for bit number bn of m, set m{bn} = 1 if */ /* x{bn} == x{bn+1} for 0 <= bn <= 30. That is, set a bit */ /* in m if the corresponding bit and the next higher bit in */ /* x are equal in value (set m{31} = 0). */ m = (~x ^ (x >> 1)) & 0x7fffffff; /* Sequences of 9 '1' bits in m now correspond to sequences */ /* of 10 '0's or 10 '1' bits in x. Shift and 'and' bits in */ /* m to find sequences of 9 or more '1' bits. As a result */ /* bits in m are set if they are at the bottom of sequences */ /* of 10 adjacent '0's or 10 adjacent '1's in x. */ m &= (m >> 1) & (m >> 2); m &= (m >> 3) & (m >> 6); if(!m) /* return if mask is empty - no key fixing needed */ /* is this early return worthwhile? */ return 0; /* We need the internal bits in each continuous sequence of */ /* matching bits (that is the bits less the two endpoints). */ /* We thus propagate each set bit into the 8 internal bits */ /* that it represents, starting 1 left and finsihing 8 left */ /* of its position. */ m <<= 1; m |= (m << 1); m |= (m << 2); m |= (m << 4); /* m is now correct except for the odd behaviour of bit 31, */ /* that is, it will be set if it is in a sequence of 10 or */ /* more '0's and clear otherwise. */ m |= (m << 1) & ~x & 0x80000000; return m & 0xfffffffc; }; /* My thanks to Louis Granboulan for spotting an error in the */ /* previous version of set_key. */ u4byte *mars_set_key(MarsContext *ctx, const u4byte in_key[], const u4byte key_len) { u4byte i, j, m, w; u4byte *l_key = ctx->l_key; m = key_len / 32 - 1; for(i = j = 0; i < 39; ++i) { vk[i + 7] = rotl(vk[i] ^ vk[i + 5], 3) ^ in_key[j] ^ i; j = (j == m ? 0 : j + 1); } vk[46] = key_len / 32; for(j = 0; j < 7; ++j) { for(i = 1; i < 40; ++i) vk[i + 7] = rotl(vk[i + 7] + s_box[vk[i + 6] & 511], 9); vk[7] = rotl(vk[7] + s_box[vk[46] & 511], 9); } for(i = j = 0; i < 40; ++i) { l_key[j] = vk[i + 7]; j = (j < 33 ? j + 7 : j - 33); } for(i = 5; i < 37; i += 2) { w = l_key[i] | 3; if((m = gen_mask(w))) w ^= (rotl(s_box[265 + (l_key[i] & 3)], l_key[i + 3] & 31) & m); l_key[i] = w; } return l_key; }; void mars_encrypt(MarsContext *ctx, const u4byte in_blk[4], u4byte out_blk[4]) { u4byte a, b, c, d, l, m, r; u4byte *l_key = ctx->l_key; a = in_blk[0] + l_key[0]; b = in_blk[1] + l_key[1]; c = in_blk[2] + l_key[2]; d = in_blk[3] + l_key[3]; f_mix(a,b,c,d); a += d; f_mix(b,c,d,a); b += c; f_mix(c,d,a,b); f_mix(d,a,b,c); f_mix(a,b,c,d); a += d; f_mix(b,c,d,a); b += c; f_mix(c,d,a,b); f_mix(d,a,b,c); f_ktr(a,b,c,d, 4); f_ktr(b,c,d,a, 6); f_ktr(c,d,a,b, 8); f_ktr(d,a,b,c,10); f_ktr(a,b,c,d,12); f_ktr(b,c,d,a,14); f_ktr(c,d,a,b,16); f_ktr(d,a,b,c,18); f_ktr(a,d,c,b,20); f_ktr(b,a,d,c,22); f_ktr(c,b,a,d,24); f_ktr(d,c,b,a,26); f_ktr(a,d,c,b,28); f_ktr(b,a,d,c,30); f_ktr(c,b,a,d,32); f_ktr(d,c,b,a,34); b_mix(a,b,c,d); b_mix(b,c,d,a); c -= b; b_mix(c,d,a,b); d -= a; b_mix(d,a,b,c); b_mix(a,b,c,d); b_mix(b,c,d,a); c -= b; b_mix(c,d,a,b); d -= a; b_mix(d,a,b,c); out_blk[0] = a - l_key[36]; out_blk[1] = b - l_key[37]; out_blk[2] = c - l_key[38]; out_blk[3] = d - l_key[39]; }; void mars_decrypt(MarsContext *ctx, const u4byte in_blk[4], u4byte out_blk[4]) { u4byte a, b, c, d, l, m, r; u4byte *l_key = ctx->l_key; d = in_blk[0] + l_key[36]; c = in_blk[1] + l_key[37]; b = in_blk[2] + l_key[38]; a = in_blk[3] + l_key[39]; f_mix(a,b,c,d); a += d; f_mix(b,c,d,a); b += c; f_mix(c,d,a,b); f_mix(d,a,b,c); f_mix(a,b,c,d); a += d; f_mix(b,c,d,a); b += c; f_mix(c,d,a,b); f_mix(d,a,b,c); r_ktr(a,b,c,d,34); r_ktr(b,c,d,a,32); r_ktr(c,d,a,b,30); r_ktr(d,a,b,c,28); r_ktr(a,b,c,d,26); r_ktr(b,c,d,a,24); r_ktr(c,d,a,b,22); r_ktr(d,a,b,c,20); r_ktr(a,d,c,b,18); r_ktr(b,a,d,c,16); r_ktr(c,b,a,d,14); r_ktr(d,c,b,a,12); r_ktr(a,d,c,b,10); r_ktr(b,a,d,c, 8); r_ktr(c,b,a,d, 6); r_ktr(d,c,b,a, 4); b_mix(a,b,c,d); b_mix(b,c,d,a); c -= b; b_mix(c,d,a,b); d -= a; b_mix(d,a,b,c); b_mix(a,b,c,d); b_mix(b,c,d,a); c -= b; b_mix(c,d,a,b); d -= a; b_mix(d,a,b,c); out_blk[0] = d - l_key[0]; out_blk[1] = c - l_key[1]; out_blk[2] = b - l_key[2]; out_blk[3] = a - l_key[3]; }