3 * The Tiny Encryption Algorithm
5 * (c) 2000 Straylight/Edgeware
8 /*----- Licensing notice --------------------------------------------------*
10 * This file is part of Catacomb.
12 * Catacomb is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU Library General Public License as
14 * published by the Free Software Foundation; either version 2 of the
15 * License, or (at your option) any later version.
17 * Catacomb is distributed in the hope that it will be useful,
18 * but WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 * GNU Library General Public License for more details.
22 * You should have received a copy of the GNU Library General Public
23 * License along with Catacomb; if not, write to the Free
24 * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
28 /*----- Header files ------------------------------------------------------*/
30 #include <mLib/bits.h>
37 /*----- Global variables --------------------------------------------------*/
39 const octet tea_keysz[] = { KSZ_RANGE, TEA_KEYSZ, 0, 16, 1 };
41 /*----- Main code ---------------------------------------------------------*/
43 /* --- @tea_init@ --- *
45 * Arguments: @tea_ctx *k@ = pointer to key block
46 * @const void *buf@ = pointer to key buffer
47 * @size_t sz@ = size of key material
51 * Use: Initializes a TEA key buffer. The key buffer must be 16
55 void tea_init(tea_ctx *k, const void *buf, size_t sz)
65 memset(kb + sz, 0, sizeof(kb) - sz);
69 k->ka = LOAD32(p + 0); k->kb = LOAD32(p + 4);
70 k->kc = LOAD32(p + 8); k->kd = LOAD32(p + 12);
77 /* --- @tea_eblk@, @tea_dblk@ --- *
79 * Arguments: @const tea_ctx *k@ = pointer to key block
80 * @const uint32 s[2]@ = pointer to source block
81 * @uint32 d[2]@ = pointer to teatination block
85 * Use: Low-level block encryption and decryption.
88 #define DELTA 0x9e3779b9
90 void tea_eblk(const tea_ctx *k, const uint32 *s, uint32 *d)
92 uint32 y = s[0], z = s[1];
93 uint32 ka = k->ka, kb = k->kb, kc = k->kc, kd = k->kd;
97 for (i = 0; i < k->r; i++) {
99 y = U32(y + (((z << 4) + ka) ^ (z + n) ^ ((z >> 5) + kb)));
100 z = U32(z + (((y << 4) + kc) ^ (y + n) ^ ((y >> 5) + kd)));
105 void tea_dblk(const tea_ctx *k, const uint32 *s, uint32 *d)
107 uint32 y = s[0], z = s[1];
108 uint32 ka = k->ka, kb = k->kb, kc = k->kc, kd = k->kd;
109 uint32 n = DELTA * k->r;
112 for (i = 0; i < k->r; i++) {
113 z = U32(z - (((y << 4) + kc) ^ (y + n) ^ ((y >> 5) + kd)));
114 y = U32(y - (((z << 4) + ka) ^ (z + n) ^ ((z >> 5) + kb)));
122 /*----- That's all, folks -------------------------------------------------*/