8b3d7f30 |
1 | /* -*-c-*- |
2 | * |
3 | * $Id: rijndael-base.c,v 1.1 2001/05/07 17:31:37 mdw Exp $ |
4 | * |
5 | * Low-level stuff for all Rijndael block sizes |
6 | * |
7 | * (c) 2001 Straylight/Edgeware |
8 | */ |
9 | |
10 | /*----- Licensing notice --------------------------------------------------* |
11 | * |
12 | * This file is part of Catacomb. |
13 | * |
14 | * Catacomb is free software; you can redistribute it and/or modify |
15 | * it under the terms of the GNU Library General Public License as |
16 | * published by the Free Software Foundation; either version 2 of the |
17 | * License, or (at your option) any later version. |
18 | * |
19 | * Catacomb is distributed in the hope that it will be useful, |
20 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
21 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
22 | * GNU Library General Public License for more details. |
23 | * |
24 | * You should have received a copy of the GNU Library General Public |
25 | * License along with Catacomb; if not, write to the Free |
26 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
27 | * MA 02111-1307, USA. |
28 | */ |
29 | |
30 | /*----- Revision history --------------------------------------------------* |
31 | * |
32 | * $Log: rijndael-base.c,v $ |
33 | * Revision 1.1 2001/05/07 17:31:37 mdw |
34 | * Centralize Rijndael tables and key scheduling. |
35 | * |
36 | */ |
37 | |
38 | /*----- Header files ------------------------------------------------------*/ |
39 | |
40 | #include <assert.h> |
41 | #include <stdio.h> |
42 | |
43 | #include <mLib/bits.h> |
44 | |
45 | #include "blkc.h" |
46 | #include "gcipher.h" |
47 | #include "rijndael.h" |
48 | #include "rijndael-base.h" |
49 | #include "rijndael-tab.h" |
50 | |
51 | /*----- Global variables --------------------------------------------------*/ |
52 | |
53 | const octet rijndael_keysz[] = { KSZ_RANGE, RIJNDAEL_KEYSZ, 4, 32, 4 }; |
54 | |
55 | /*----- Constant tables ---------------------------------------------------*/ |
56 | |
57 | const octet rijndael_s[256] = RIJNDAEL_S; |
58 | const octet rijndael_si[256] = RIJNDAEL_SI; |
59 | const uint32 rijndael_t[4][256] = RIJNDAEL_T; |
60 | const uint32 rijndael_ti[4][256] = RIJNDAEL_TI; |
61 | const uint32 rijndael_u[4][256] = RIJNDAEL_U; |
62 | const octet rijndael_rcon[] = RIJNDAEL_RCON; |
63 | |
64 | /*----- Main code ---------------------------------------------------------*/ |
65 | |
66 | /* --- @rijndael_setup@ --- * |
67 | * |
68 | * Arguments: @rijndael_ctx *k@ = pointer to context to initialize |
69 | * @unsigned nb@ = number of words in the block |
70 | * @const void *buf@ = pointer to buffer of key material |
71 | * @size_t sz@ = size of the key material |
72 | * |
73 | * Returns: --- |
74 | * |
75 | * Use: Low-level key-scheduling. |
76 | */ |
77 | |
78 | void rijndael_setup(rijndael_ctx *k, unsigned nb, const void *buf, size_t sz) |
79 | { |
80 | unsigned nk, nr, nw; |
81 | unsigned i, j, jj; |
82 | const octet *p; |
83 | uint32 ww; |
84 | |
85 | /* --- Sort out the key size --- */ |
86 | |
87 | KSZ_ASSERT(rijndael, sz); |
88 | nk = sz / 4; |
89 | |
90 | /* --- Select the number of rounds --- */ |
91 | |
92 | nr = (nk > nb ? nk : nb) + 6; |
93 | if (nr < 10) |
94 | nr = 10; |
95 | k->nr = nr; |
96 | |
97 | /* --- Fetch the first key words out --- */ |
98 | |
99 | p = buf; |
100 | for (i = 0; i < nk; i++) { |
101 | k->w[i] = LOAD32_L(p); |
102 | p += 4; |
103 | } |
104 | |
105 | /* --- Expand this material to fill the rest of the table --- */ |
106 | |
107 | nw = (nr + 1) * nb; |
108 | ww = k->w[i - 1]; |
109 | p = RCON; |
110 | for (; i < nw; i++) { |
111 | uint32 w = k->w[i - nk]; |
112 | if (i % nk == 0) { |
113 | ww = ROR32(ww, 8); |
114 | w ^= SUB(S, ww, ww, ww, ww) ^ *p++; |
115 | } else if (nk > 6 && i % nk == 4) |
116 | w ^= SUB(S, ww, ww, ww, ww); |
117 | else |
118 | w ^= ww; |
119 | k->w[i] = ww = w; |
120 | } |
121 | |
122 | /* --- Make the decryption keys --- */ |
123 | |
124 | j = nw; i = 0; |
125 | |
126 | j -= nb; jj = 0; |
127 | for (; i < nb; i++) |
128 | k->wi[i] = k->w[j + jj++]; |
129 | |
130 | for (; i < nw - nb; i += nb) { |
131 | j -= nb; |
132 | for (jj = 0; jj < nb; jj++) { |
133 | uint32 w = k->w[j + jj]; |
134 | k->wi[i + jj] = MIX(U, w, w, w, w); |
135 | } |
136 | } |
137 | |
138 | j -= nb; jj = 0; |
139 | for (; i < nw; i++) |
140 | k->wi[i] = k->w[j + jj++]; |
141 | } |
142 | |
143 | /*----- That's all, folks -------------------------------------------------*/ |