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1 | /* crypto/bn/bn_mpi.c */ |
2 | /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) | |
3 | * All rights reserved. | |
4 | * | |
5 | * This package is an SSL implementation written | |
6 | * by Eric Young (eay@cryptsoft.com). | |
7 | * The implementation was written so as to conform with Netscapes SSL. | |
8 | * | |
9 | * This library is free for commercial and non-commercial use as long as | |
10 | * the following conditions are aheared to. The following conditions | |
11 | * apply to all code found in this distribution, be it the RC4, RSA, | |
12 | * lhash, DES, etc., code; not just the SSL code. The SSL documentation | |
13 | * included with this distribution is covered by the same copyright terms | |
14 | * except that the holder is Tim Hudson (tjh@cryptsoft.com). | |
15 | * | |
16 | * Copyright remains Eric Young's, and as such any Copyright notices in | |
17 | * the code are not to be removed. | |
18 | * If this package is used in a product, Eric Young should be given attribution | |
19 | * as the author of the parts of the library used. | |
20 | * This can be in the form of a textual message at program startup or | |
21 | * in documentation (online or textual) provided with the package. | |
22 | * | |
23 | * Redistribution and use in source and binary forms, with or without | |
24 | * modification, are permitted provided that the following conditions | |
25 | * are met: | |
26 | * 1. Redistributions of source code must retain the copyright | |
27 | * notice, this list of conditions and the following disclaimer. | |
28 | * 2. Redistributions in binary form must reproduce the above copyright | |
29 | * notice, this list of conditions and the following disclaimer in the | |
30 | * documentation and/or other materials provided with the distribution. | |
31 | * 3. All advertising materials mentioning features or use of this software | |
32 | * must display the following acknowledgement: | |
33 | * "This product includes cryptographic software written by | |
34 | * Eric Young (eay@cryptsoft.com)" | |
35 | * The word 'cryptographic' can be left out if the rouines from the library | |
36 | * being used are not cryptographic related :-). | |
37 | * 4. If you include any Windows specific code (or a derivative thereof) from | |
38 | * the apps directory (application code) you must include an acknowledgement: | |
39 | * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" | |
40 | * | |
41 | * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND | |
42 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
43 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
44 | * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE | |
45 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | |
46 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS | |
47 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |
48 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | |
49 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY | |
50 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | |
51 | * SUCH DAMAGE. | |
52 | * | |
53 | * The licence and distribution terms for any publically available version or | |
54 | * derivative of this code cannot be changed. i.e. this code cannot simply be | |
55 | * copied and put under another distribution licence | |
56 | * [including the GNU Public Licence.] | |
57 | */ | |
58 | ||
59 | #include <stdio.h> | |
60 | #include "cryptlib.h" | |
61 | #include "bn_lcl.h" | |
62 | ||
63 | int BN_bn2mpi(a,d) | |
64 | BIGNUM *a; | |
65 | unsigned char *d; | |
66 | { | |
67 | int bits; | |
68 | int num=0; | |
69 | int ext=0; | |
70 | long l; | |
71 | ||
72 | bits=BN_num_bits(a); | |
73 | num=(bits+7)/8; | |
74 | if (bits > 0) | |
75 | { | |
76 | ext=((bits & 0x07) == 0); | |
77 | } | |
78 | if (d == NULL) | |
79 | return(num+4+ext); | |
80 | ||
81 | l=num+ext; | |
82 | d[0]=(unsigned char)(l>>24)&0xff; | |
83 | d[1]=(unsigned char)(l>>16)&0xff; | |
84 | d[2]=(unsigned char)(l>> 8)&0xff; | |
85 | d[3]=(unsigned char)(l )&0xff; | |
86 | if (ext) d[4]=0; | |
87 | num=BN_bn2bin(a,&(d[4+ext])); | |
88 | if (a->neg) | |
89 | d[4]|=0x80; | |
90 | return(num+4+ext); | |
91 | } | |
92 | ||
93 | BIGNUM *BN_mpi2bn(d,n,a) | |
94 | unsigned char *d; | |
95 | int n; | |
96 | BIGNUM *a; | |
97 | { | |
98 | long len; | |
99 | int neg=0; | |
100 | ||
101 | if (n < 4) | |
102 | { | |
103 | BNerr(BN_F_BN_MPI2BN,BN_R_INVALID_LENGTH); | |
104 | return(NULL); | |
105 | } | |
106 | len=(d[0]<<24)|(d[1]<<16)|(d[2]<<8)|d[3]; | |
107 | if ((len+4) != n) | |
108 | { | |
109 | BNerr(BN_F_BN_MPI2BN,BN_R_ENCODING_ERROR); | |
110 | return(NULL); | |
111 | } | |
112 | ||
113 | if (a == NULL) a=BN_new(); | |
114 | if (a == NULL) return(NULL); | |
115 | ||
116 | if (len == 0) | |
117 | { | |
118 | a->neg=0; | |
119 | a->top=0; | |
120 | return(a); | |
121 | } | |
122 | d+=4; | |
123 | if ((*d) & 0x80) | |
124 | neg=1; | |
125 | if (BN_bin2bn(d,(int)len,a) == NULL) | |
126 | return(NULL); | |
127 | a->neg=neg; | |
128 | if (neg) | |
129 | { | |
130 | BN_clear_bit(a,BN_num_bits(a)-1); | |
131 | } | |
132 | return(a); | |
133 | } | |
134 |