Commit | Line | Data |
---|---|---|
fdf53e02 GW |
1 | /* |
2 | * $Source: /afs/athena.mit.edu/astaff/project/kerberos/src/lib/des/RCS/cksum.c,v $ | |
3 | * $Author: jtkohl $ | |
4 | * | |
5 | * Copyright 1985, 1986, 1987, 1988 by the Massachusetts Institute | |
6 | * of Technology. | |
7 | * | |
8 | * For copying and distribution information, please see the file | |
9 | * <mit-copyright.h>. | |
10 | * | |
11 | * These routines perform encryption and decryption using the DES | |
12 | * private key algorithm, or else a subset of it-- fewer inner loops. | |
13 | * (AUTH_DES_ITER defaults to 16, may be less.) | |
14 | * | |
15 | * Under U.S. law, this software may not be exported outside the US | |
16 | * without license from the U.S. Commerce department. | |
17 | * | |
18 | * These routines form the library interface to the DES facilities. | |
19 | * | |
20 | * spm 8/85 MIT project athena | |
21 | */ | |
22 | ||
23 | #ifndef lint | |
24 | static char rcsid_cksum_c[] = | |
25 | "$Id: cksum.c,v 4.10 90/01/02 13:46:25 jtkohl Exp $"; | |
26 | #endif lint | |
27 | ||
28 | #include <mit-copyright.h> | |
29 | #include <stdio.h> | |
30 | #include <strings.h> | |
31 | ||
32 | #include <des.h> | |
33 | #include "des_internal.h" | |
34 | ||
35 | extern int des_debug; | |
36 | extern int des_debug_print(); | |
37 | ||
38 | /* | |
39 | * This routine performs DES cipher-block-chaining checksum operation, | |
40 | * a.k.a. Message Authentication Code. It ALWAYS encrypts from input | |
41 | * to a single 64 bit output MAC checksum. | |
42 | * | |
43 | * The key schedule is passed as an arg, as well as the cleartext or | |
44 | * ciphertext. The cleartext and ciphertext should be in host order. | |
45 | * | |
46 | * NOTE-- the output is ALWAYS 8 bytes long. If not enough space was | |
47 | * provided, your program will get trashed. | |
48 | * | |
49 | * The input is null padded, at the end (highest addr), to an integral | |
50 | * multiple of eight bytes. | |
51 | */ | |
52 | ||
53 | unsigned long | |
54 | des_cbc_cksum(in,out,length,key,iv) | |
55 | des_cblock *in; /* >= length bytes of inputtext */ | |
56 | des_cblock *out; /* >= length bytes of outputtext */ | |
57 | register long length; /* in bytes */ | |
58 | des_key_schedule key; /* precomputed key schedule */ | |
59 | des_cblock *iv; /* 8 bytes of ivec */ | |
60 | { | |
61 | register unsigned long *input = (unsigned long *) in; | |
62 | register unsigned long *output = (unsigned long *) out; | |
63 | unsigned long *ivec = (unsigned long *) iv; | |
64 | ||
65 | unsigned long i,j; | |
66 | static unsigned long t_input[2]; | |
67 | static unsigned long t_output[8]; | |
68 | static unsigned char *t_in_p; | |
69 | ||
70 | t_in_p = (unsigned char *) t_input; | |
71 | #ifdef MUSTALIGN | |
72 | if ((long) ivec & 3) { | |
73 | bcopy((char *)ivec++,(char *)&t_output[0],sizeof(t_output[0])); | |
74 | bcopy((char *)ivec,(char *)&t_output[1],sizeof(t_output[1])); | |
75 | } | |
76 | else | |
77 | #endif | |
78 | { | |
79 | t_output[0] = *ivec++; | |
80 | t_output[1] = *ivec; | |
81 | } | |
82 | ||
83 | for (i = 0; length > 0; i++, length -= 8) { | |
84 | /* get input */ | |
85 | #ifdef MUSTALIGN | |
86 | if ((long) input & 3) { | |
87 | bcopy((char *)input++,(char *)&t_input[0],sizeof(t_input[0])); | |
88 | bcopy((char *)input++,(char *)&t_input[1],sizeof(t_input[1])); | |
89 | } | |
90 | else | |
91 | #endif | |
92 | { | |
93 | t_input[0] = *input++; | |
94 | t_input[1] = *input++; | |
95 | } | |
96 | ||
97 | /* zero pad */ | |
98 | if (length < 8) | |
99 | for (j = length; j <= 7; j++) | |
100 | *(t_in_p+j)= 0; | |
101 | ||
102 | #ifdef DEBUG | |
103 | if (des_debug) | |
104 | des_debug_print("clear",length,t_input[0],t_input[1]); | |
105 | #endif | |
106 | /* do the xor for cbc into the temp */ | |
107 | t_input[0] ^= t_output[0] ; | |
108 | t_input[1] ^= t_output[1] ; | |
109 | /* encrypt */ | |
110 | (void) des_ecb_encrypt(t_input,t_output,key,1); | |
111 | #ifdef DEBUG | |
112 | if (des_debug) { | |
113 | des_debug_print("xor'ed",i,t_input[0],t_input[1]); | |
114 | des_debug_print("cipher",i,t_output[0],t_output[1]); | |
115 | } | |
116 | #else | |
117 | #ifdef lint | |
118 | i = i; | |
119 | #endif | |
120 | #endif | |
121 | } | |
122 | /* copy temp output and save it for checksum */ | |
123 | #ifdef MUSTALIGN | |
124 | if ((long) output & 3) { | |
125 | bcopy((char *)&t_output[0],(char *)output++,sizeof(t_output[0])); | |
126 | bcopy((char *)&t_output[1],(char *)output,sizeof(t_output[1])); | |
127 | } | |
128 | else | |
129 | #endif | |
130 | { | |
131 | *output++ = t_output[0]; | |
132 | *output = t_output[1]; | |
133 | } | |
134 | ||
135 | return (unsigned long) t_output[1]; | |
136 | } |