1 /* crypto/bn/bn_mpi.c */ 2 /* Copyright (C) 1995-1998 Eric Young (eay (at) cryptsoft.com) 3 * All rights reserved. 4 * 5 * This package is an SSL implementation written 6 * by Eric Young (eay (at) 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 (at) 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 (at) 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 (at) 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(const BIGNUM *a, unsigned char *d) 64 { 65 int bits; 66 int num=0; 67 int ext=0; 68 long l; 69 70 bits=BN_num_bits(a); 71 num=(bits+7)/8; 72 if (bits > 0) 73 { 74 ext=((bits & 0x07) == 0); 75 } 76 if (d == NULL) 77 return(num+4+ext); 78 79 l=num+ext; 80 d[0]=(unsigned char)(l>>24)&0xff; 81 d[1]=(unsigned char)(l>>16)&0xff; 82 d[2]=(unsigned char)(l>> 8)&0xff; 83 d[3]=(unsigned char)(l )&0xff; 84 if (ext) d[4]=0; 85 num=BN_bn2bin(a,&(d[4+ext])); 86 if (a->neg) 87 d[4]|=0x80; 88 return(num+4+ext); 89 } 90 91 BIGNUM *BN_mpi2bn(const unsigned char *d, int n, BIGNUM *a) 92 { 93 long len; 94 int neg=0; 95 96 if (n < 4) 97 { 98 BNerr(BN_F_BN_MPI2BN,BN_R_INVALID_LENGTH); 99 return(NULL); 100 } 101 len=((long)d[0]<<24)|((long)d[1]<<16)|((int)d[2]<<8)|(int)d[3]; 102 if ((len+4) != n) 103 { 104 BNerr(BN_F_BN_MPI2BN,BN_R_ENCODING_ERROR); 105 return(NULL); 106 } 107 108 if (a == NULL) a=BN_new(); 109 if (a == NULL) return(NULL); 110 111 if (len == 0) 112 { 113 a->neg=0; 114 a->top=0; 115 return(a); 116 } 117 d+=4; 118 if ((*d) & 0x80) 119 neg=1; 120 if (BN_bin2bn(d,(int)len,a) == NULL) 121 return(NULL); 122 a->neg=neg; 123 if (neg) 124 { 125 BN_clear_bit(a,BN_num_bits(a)-1); 126 } 127 bn_check_top(a); 128 return(a); 129 } 130 131
