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