2 * Copyright 1985, 1986, 1987, 1988 by the Massachusetts Institute
5 * For copying and distribution information, please see the file
8 * These routines perform encryption and decryption using the DES
9 * private key algorithm, or else a subset of it-- fewer inner loops.
10 * (AUTH_DES_ITER defaults to 16, may be less.)
12 * Under U.S. law, this software may not be exported outside the US
13 * without license from the U.S. Commerce department.
15 * These routines form the library interface to the DES facilities.
17 * spm 8/85 MIT project athena
20 #include <afsconfig.h>
21 #include <afs/param.h>
25 #include <mit-cpyright.h>
38 #include "des_internal.h"
39 #include "des_prototypes.h"
44 * This routine performs DES cipher-block-chaining checksum operation,
45 * a.k.a. Message Authentication Code. It ALWAYS encrypts from input
46 * to a single 64 bit output MAC checksum.
48 * The key schedule is passed as an arg, as well as the cleartext or
49 * ciphertext. The cleartext and ciphertext should be in host order.
51 * NOTE-- the output is ALWAYS 8 bytes long. If not enough space was
52 * provided, your program will get trashed.
54 * The input is null padded, at the end (highest addr), to an integral
55 * multiple of eight bytes.
58 des_cblock *in; * >= length bytes of inputtext *
59 des_cblock *out; * >= length bytes of outputtext *
60 register afs_int32 length; * in bytes *
61 des_key_schedule key; * precomputed key schedule *
62 des_cblock *iv; * 8 bytes of ivec *
65 afs_uint32 des_cbc_cksum(des_cblock *in, des_cblock *out,
66 register afs_int32 length, des_key_schedule key, des_cblock *iv)
68 register afs_uint32 *input = (afs_uint32 *) in;
69 register afs_uint32 *output = (afs_uint32 *) out;
70 afs_uint32 *ivec = (afs_uint32 *) iv;
73 afs_uint32 t_input[2];
74 afs_uint32 t_output[8];
75 unsigned char *t_in_p = (unsigned char *) t_input;
78 if ((afs_int32) ivec & 3) {
79 memcpy((char *)&t_output[0], (char *)ivec++, sizeof(t_output[0]));
80 memcpy((char *)&t_output[1], (char *)ivec, sizeof(t_output[1]));
85 t_output[0] = *ivec++;
89 for (i = 0; length > 0; i++, length -= 8) {
92 if ((afs_int32) input & 3) {
93 memcpy((char *)&t_input[0], (char *)input++, sizeof(t_input[0]));
94 memcpy((char *)&t_input[1], (char *)input++, sizeof(t_input[1]));
99 t_input[0] = *input++;
100 t_input[1] = *input++;
105 for (j = length; j <= 7; j++)
110 des_debug_print("clear",length,t_input[0],t_input[1]);
112 /* do the xor for cbc into the temp */
113 t_input[0] ^= t_output[0] ;
114 t_input[1] ^= t_output[1] ;
116 (void) des_ecb_encrypt(t_input,t_output,key,1);
119 des_debug_print("xor'ed",i,t_input[0],t_input[1]);
120 des_debug_print("cipher",i,t_output[0],t_output[1]);
128 /* copy temp output and save it for checksum */
130 if ((afs_int32) output & 3) {
131 memcpy((char *)output++, (char *)&t_output[0], sizeof(t_output[0]));
132 memcpy((char *)output, (char *)&t_output[1], sizeof(t_output[1]));
137 *output++ = t_output[0];
138 *output = t_output[1];
141 return (afs_uint32) t_output[1];