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crypt.h
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1 /*
2 * Copyright (c) 1989, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * Tom Truscott.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of the University nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33 #ifndef CRYPT_H
34 #define CRYPT_H 1
35
36 /* ===== Configuration ==================== */
37
38 #ifdef CHAR_BITS
39 #if CHAR_BITS != 8
40 #error C_block structure assumes 8 bit characters
41 #endif
42 #endif
43
44 #ifndef LONG_LONG
45 # if SIZEOF_LONG_LONG > 0
46 # define LONG_LONG long long
47 # elif SIZEOF___INT64 > 0
48 # define HAVE_LONG_LONG 1
49 # define LONG_LONG __int64
50 # undef SIZEOF_LONG_LONG
51 # define SIZEOF_LONG_LONG SIZEOF___INT64
52 # endif
53 #endif
54
55 /*
56 * define "LONG_IS_32_BITS" only if sizeof(long)==4.
57 * This avoids use of bit fields (your compiler may be sloppy with them).
58 */
59 #if SIZEOF_LONG == 4
60 #define LONG_IS_32_BITS
61 #endif
62
63 /*
64 * define "B64" to be the declaration for a 64 bit integer.
65 * XXX this feature is currently unused, see "endian" comment below.
66 */
67 #if SIZEOF_LONG == 8
68 #define B64 long
69 #elif SIZEOF_LONG_LONG == 8
70 #define B64 LONG_LONG
71 #endif
72
73 /*
74 * define "LARGEDATA" to get faster permutations, by using about 72 kilobytes
75 * of lookup tables. This speeds up des_setkey() and des_cipher(), but has
76 * little effect on crypt().
77 */
78 #if defined(notdef)
79 #define LARGEDATA
80 #endif
81
82 /* compile with "-DSTATIC=int" when profiling */
83 #ifndef STATIC
84 #define STATIC static
85 #endif
86
87 /* ==================================== */
88
89 /*
90 * Cipher-block representation (Bob Baldwin):
91 *
92 * DES operates on groups of 64 bits, numbered 1..64 (sigh). One
93 * representation is to store one bit per byte in an array of bytes. Bit N of
94 * the NBS spec is stored as the LSB of the Nth byte (index N-1) in the array.
95 * Another representation stores the 64 bits in 8 bytes, with bits 1..8 in the
96 * first byte, 9..16 in the second, and so on. The DES spec apparently has
97 * bit 1 in the MSB of the first byte, but that is particularly noxious so we
98 * bit-reverse each byte so that bit 1 is the LSB of the first byte, bit 8 is
99 * the MSB of the first byte. Specifically, the 64-bit input data and key are
100 * converted to LSB format, and the output 64-bit block is converted back into
101 * MSB format.
102 *
103 * DES operates internally on groups of 32 bits which are expanded to 48 bits
104 * by permutation E and shrunk back to 32 bits by the S boxes. To speed up
105 * the computation, the expansion is applied only once, the expanded
106 * representation is maintained during the encryption, and a compression
107 * permutation is applied only at the end. To speed up the S-box lookups,
108 * the 48 bits are maintained as eight 6 bit groups, one per byte, which
109 * directly feed the eight S-boxes. Within each byte, the 6 bits are the
110 * most significant ones. The low two bits of each byte are zero. (Thus,
111 * bit 1 of the 48 bit E expansion is stored as the "4"-valued bit of the
112 * first byte in the eight byte representation, bit 2 of the 48 bit value is
113 * the "8"-valued bit, and so on.) In fact, a combined "SPE"-box lookup is
114 * used, in which the output is the 64 bit result of an S-box lookup which
115 * has been permuted by P and expanded by E, and is ready for use in the next
116 * iteration. Two 32-bit wide tables, SPE[0] and SPE[1], are used for this
117 * lookup. Since each byte in the 48 bit path is a multiple of four, indexed
118 * lookup of SPE[0] and SPE[1] is simple and fast. The key schedule and
119 * "salt" are also converted to this 8*(6+2) format. The SPE table size is
120 * 8*64*8 = 4K bytes.
121 *
122 * To speed up bit-parallel operations (such as XOR), the 8 byte
123 * representation is "union"ed with 32 bit values "i0" and "i1", and, on
124 * machines which support it, a 64 bit value "b64". This data structure,
125 * "C_block", has two problems. First, alignment restrictions must be
126 * honored. Second, the byte-order (e.g. little-endian or big-endian) of
127 * the architecture becomes visible.
128 *
129 * The byte-order problem is unfortunate, since on the one hand it is good
130 * to have a machine-independent C_block representation (bits 1..8 in the
131 * first byte, etc.), and on the other hand it is good for the LSB of the
132 * first byte to be the LSB of i0. We cannot have both these things, so we
133 * currently use the "little-endian" representation and avoid any multi-byte
134 * operations that depend on byte order. This largely precludes use of the
135 * 64-bit datatype since the relative order of i0 and i1 are unknown. It
136 * also inhibits grouping the SPE table to look up 12 bits at a time. (The
137 * 12 bits can be stored in a 16-bit field with 3 low-order zeroes and 1
138 * high-order zero, providing fast indexing into a 64-bit wide SPE.) On the
139 * other hand, 64-bit datatypes are currently rare, and a 12-bit SPE lookup
140 * requires a 128 kilobyte table, so perhaps this is not a big loss.
141 *
142 * Permutation representation (Jim Gillogly):
143 *
144 * A transformation is defined by its effect on each of the 8 bytes of the
145 * 64-bit input. For each byte we give a 64-bit output that has the bits in
146 * the input distributed appropriately. The transformation is then the OR
147 * of the 8 sets of 64-bits. This uses 8*256*8 = 16K bytes of storage for
148 * each transformation. Unless LARGEDATA is defined, however, a more compact
149 * table is used which looks up 16 4-bit "chunks" rather than 8 8-bit chunks.
150 * The smaller table uses 16*16*8 = 2K bytes for each transformation. This
151 * is slower but tolerable, particularly for password encryption in which
152 * the SPE transformation is iterated many times. The small tables total 9K
153 * bytes, the large tables total 72K bytes.
154 *
155 * The transformations used are:
156 * IE3264: MSB->LSB conversion, initial permutation, and expansion.
157 * This is done by collecting the 32 even-numbered bits and applying
158 * a 32->64 bit transformation, and then collecting the 32 odd-numbered
159 * bits and applying the same transformation. Since there are only
160 * 32 input bits, the IE3264 transformation table is half the size of
161 * the usual table.
162 * CF6464: Compression, final permutation, and LSB->MSB conversion.
163 * This is done by two trivial 48->32 bit compressions to obtain
164 * a 64-bit block (the bit numbering is given in the "CIFP" table)
165 * followed by a 64->64 bit "cleanup" transformation. (It would
166 * be possible to group the bits in the 64-bit block so that 2
167 * identical 32->32 bit transformations could be used instead,
168 * saving a factor of 4 in space and possibly 2 in time, but
169 * byte-ordering and other complications rear their ugly head.
170 * Similar opportunities/problems arise in the key schedule
171 * transforms.)
172 * PC1ROT: MSB->LSB, PC1 permutation, rotate, and PC2 permutation.
173 * This admittedly baroque 64->64 bit transformation is used to
174 * produce the first code (in 8*(6+2) format) of the key schedule.
175 * PC2ROT[0]: Inverse PC2 permutation, rotate, and PC2 permutation.
176 * It would be possible to define 15 more transformations, each
177 * with a different rotation, to generate the entire key schedule.
178 * To save space, however, we instead permute each code into the
179 * next by using a transformation that "undoes" the PC2 permutation,
180 * rotates the code, and then applies PC2. Unfortunately, PC2
181 * transforms 56 bits into 48 bits, dropping 8 bits, so PC2 is not
182 * invertible. We get around that problem by using a modified PC2
183 * which retains the 8 otherwise-lost bits in the unused low-order
184 * bits of each byte. The low-order bits are cleared when the
185 * codes are stored into the key schedule.
186 * PC2ROT[1]: Same as PC2ROT[0], but with two rotations.
187 * This is faster than applying PC2ROT[0] twice,
188 *
189 * The Bell Labs "salt" (Bob Baldwin):
190 *
191 * The salting is a simple permutation applied to the 48-bit result of E.
192 * Specifically, if bit i (1 <= i <= 24) of the salt is set then bits i and
193 * i+24 of the result are swapped. The salt is thus a 24 bit number, with
194 * 16777216 possible values. (The original salt was 12 bits and could not
195 * swap bits 13..24 with 36..48.)
196 *
197 * It is possible, but ugly, to warp the SPE table to account for the salt
198 * permutation. Fortunately, the conditional bit swapping requires only
199 * about four machine instructions and can be done on-the-fly with about an
200 * 8% performance penalty.
201 */
202
203 typedef union {
204 unsigned char b[8];
205 struct {
206 #if defined(LONG_IS_32_BITS)
207 /* long is often faster than a 32-bit bit field */
208 long i0;
209 long i1;
210 #else
211 long i0: 32;
212 long i1: 32;
213 #endif
214 } b32;
215 #if defined(B64)
216 B64 b64;
217 #endif
218 } C_block;
219
220 #if defined(LARGEDATA)
221 /* Waste memory like crazy. Also, do permutations in line */
222 #define LGCHUNKBITS 3
223 #define CHUNKBITS (1<<LGCHUNKBITS)
224 #else
225 /* "small data" */
226 #define LGCHUNKBITS 2
227 #define CHUNKBITS (1<<LGCHUNKBITS)
228 #endif
229
230 struct crypt_data {
231 /* The Key Schedule, filled in by des_setkey() or setkey(). */
232 #define KS_SIZE 16
233 C_block KS[KS_SIZE];
234
235 /* ==================================== */
236
237 char cryptresult[1+4+4+11+1]; /* encrypted result */
238 };
239
240 char *crypt(const char *key, const char *setting);
241 void setkey(const char *key);
242 void encrypt(char *block, int flag);
243
244 char *crypt_r(const char *key, const char *setting, struct crypt_data *data);
245 void setkey_r(const char *key, struct crypt_data *data);
246 void encrypt_r(char *block, int flag, struct crypt_data *data);
247
248 #endif /* CRYPT_H */
crypt_data::cryptresult
char cryptresult[1+4+4+11+1]
Definition: crypt.h:237
crypt_r
char * crypt_r(const char *key, const char *setting, struct crypt_data *data)
Definition: crypt.c:396
crypt_data
Definition: crypt.h:230
KS_SIZE
#define KS_SIZE
Definition: crypt.h:232
crypt_data::KS
C_block KS[KS_SIZE]
Definition: crypt.h:233
key
key
Definition: openssl_missing.h:181
C_block::i0
long i0
Definition: crypt.h:211
C_block::i1
long i1
Definition: crypt.h:212
crypt
char * crypt(const char *key, const char *setting)
setkey
void setkey(const char *key)
setkey_r
void setkey_r(const char *key, struct crypt_data *data)
Definition: crypt.c:807
encrypt
void encrypt(char *block, int flag)
C_block
Definition: crypt.h:203
encrypt_r
void encrypt_r(char *block, int flag, struct crypt_data *data)
Definition: crypt.c:835