2 * Copyright (c) 1999 Kungliga Tekniska Högskolan
3 * (Royal Institute of Technology, Stockholm, Sweden).
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
10 * 1. Redistributions of source code must retain the above copyright
11 * 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.
17 * 3. Neither the name of KTH nor the names of its contributors may be
18 * used to endorse or promote products derived from this software without
19 * specific prior written permission.
21 * THIS SOFTWARE IS PROVIDED BY KTH AND ITS CONTRIBUTORS ``AS IS'' AND ANY
22 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
24 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL KTH OR ITS CONTRIBUTORS BE
25 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
26 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
27 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
28 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
29 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
30 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
31 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */
33 #include "krb5_locl.h"
35 RCSID("$Id: n-fold.c,v 1.6 1999/08/27 09:03:41 joda Exp $");
38 rr13(unsigned char *buf, size_t len)
41 int bytes = (len + 7) / 8;
46 const int bits = 13 % len;
47 const int lbit = len % 8;
50 memcpy(tmp, buf, bytes);
52 /* pad final byte with inital bits */
53 tmp[bytes - 1] &= 0xff << (8 - lbit);
54 for(i = lbit; i < 8; i += len)
55 tmp[bytes - 1] |= buf[0] >> i;
57 for(i = 0; i < bytes; i++) {
60 /* calculate first bit position of this byte */
64 /* byte offset and shift count */
68 if(bb + 8 > bytes * 8)
69 /* watch for wraparound */
70 s2 = (len + 8 - s1) % 8;
73 b2 = (b1 + 1) % bytes;
74 buf[i] = (tmp[b1] << s1) | (tmp[b2] >> s2);
80 /* Add `b' to `a', both beeing one's complement numbers. */
82 add1(unsigned char *a, unsigned char *b, size_t len)
86 for(i = len - 1; i >= 0; i--){
87 int x = a[i] + b[i] + carry;
91 for(i = len - 1; carry && i >= 0; i--){
99 _krb5_n_fold(const void *str, size_t len, void *key, size_t size)
101 /* if len < size we need at most N * len bytes, ie < 2 * size;
102 if len > size we need at most 2 * len */
103 size_t maxlen = 2 * max(size, len);
105 unsigned char *tmp = malloc(maxlen);
106 unsigned char *buf = malloc(len);
108 memcpy(buf, str, len);
109 memset(key, 0, size);
111 memcpy(tmp + l, buf, len);
115 add1(key, tmp, size);
119 memmove(tmp, tmp + size, l);
124 memset(tmp, 0, maxlen);