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>
36 #include "des_internal.h"
41 extern int des_debug_print();
42 extern int des_ecb_encrypt();
45 * This routine performs DES cipher-block-chaining checksum operation,
46 * a.k.a. Message Authentication Code. It ALWAYS encrypts from input
47 * to a single 64 bit output MAC checksum.
49 * The key schedule is passed as an arg, as well as the cleartext or
50 * ciphertext. The cleartext and ciphertext should be in host order.
52 * NOTE-- the output is ALWAYS 8 bytes long. If not enough space was
53 * provided, your program will get trashed.
55 * The input is null padded, at the end (highest addr), to an integral
56 * multiple of eight bytes.
60 des_cbc_cksum(in,out,length,key,iv)
61 des_cblock *in; /* >= length bytes of inputtext */
62 des_cblock *out; /* >= length bytes of outputtext */
63 register afs_int32 length; /* in bytes */
64 des_key_schedule key; /* precomputed key schedule */
65 des_cblock *iv; /* 8 bytes of ivec */
67 register afs_uint32 *input = (afs_uint32 *) in;
68 register afs_uint32 *output = (afs_uint32 *) out;
69 afs_uint32 *ivec = (afs_uint32 *) iv;
72 afs_uint32 t_input[2];
73 afs_uint32 t_output[8];
74 unsigned char *t_in_p = (unsigned char *) t_input;
77 if ((afs_int32) ivec & 3) {
78 bcopy((char *)ivec++,(char *)&t_output[0],sizeof(t_output[0]));
79 bcopy((char *)ivec,(char *)&t_output[1],sizeof(t_output[1]));
84 t_output[0] = *ivec++;
88 for (i = 0; length > 0; i++, length -= 8) {
91 if ((afs_int32) input & 3) {
92 bcopy((char *)input++,(char *)&t_input[0],sizeof(t_input[0]));
93 bcopy((char *)input++,(char *)&t_input[1],sizeof(t_input[1]));
98 t_input[0] = *input++;
99 t_input[1] = *input++;
104 for (j = length; j <= 7; j++)
109 des_debug_print("clear",length,t_input[0],t_input[1]);
111 /* do the xor for cbc into the temp */
112 t_input[0] ^= t_output[0] ;
113 t_input[1] ^= t_output[1] ;
115 (void) des_ecb_encrypt(t_input,t_output,key,1);
118 des_debug_print("xor'ed",i,t_input[0],t_input[1]);
119 des_debug_print("cipher",i,t_output[0],t_output[1]);
127 /* copy temp output and save it for checksum */
129 if ((afs_int32) output & 3) {
130 bcopy((char *)&t_output[0],(char *)output++,sizeof(t_output[0]));
131 bcopy((char *)&t_output[1],(char *)output,sizeof(t_output[1]));
136 *output++ = t_output[0];
137 *output = t_output[1];
140 return (afs_uint32) t_output[1];