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1 /* crypto/des/cfb_enc.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 "e_os.h" |
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60 #include "des_locl.h" |
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61 #include <assert.h> |
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62 |
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63 /* The input and output are loaded in multiples of 8 bits. |
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64 * What this means is that if you hame numbits=12 and length=2 |
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65 * the first 12 bits will be retrieved from the first byte and half |
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66 * the second. The second 12 bits will come from the 3rd and half the 4th |
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67 * byte. |
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68 */ |
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69 /* Until Aug 1 2003 this function did not correctly implement CFB-r, so it |
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70 * will not be compatible with any encryption prior to that date. Ben. */ |
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71 EXPORT_C void DES_cfb_encrypt(const unsigned char *in, unsigned char *out, int numbits, |
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72 long length, DES_key_schedule *schedule, DES_cblock *ivec, |
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73 int enc) |
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74 { |
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75 register DES_LONG d0,d1,v0,v1; |
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76 register unsigned long l=length; |
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77 register int num=numbits/8,n=(numbits+7)/8,i,rem=numbits%8; |
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78 DES_LONG ti[2]; |
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79 unsigned char *iv; |
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80 #ifndef L_ENDIAN |
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81 unsigned char ovec[16]; |
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82 #else |
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83 unsigned int sh[4]; |
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84 unsigned char *ovec=(unsigned char *)sh; |
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85 |
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86 /* I kind of count that compiler optimizes away this assertioni,*/ |
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87 assert (sizeof(sh[0])==4); /* as this holds true for all, */ |
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88 /* but 16-bit platforms... */ |
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89 |
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90 #endif |
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91 |
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92 if (numbits<=0 || numbits > 64) return; |
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93 iv = &(*ivec)[0]; |
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94 c2l(iv,v0); |
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95 c2l(iv,v1); |
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96 if (enc) |
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97 { |
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98 while (l >= (unsigned long)n) |
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99 { |
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100 l-=n; |
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101 ti[0]=v0; |
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102 ti[1]=v1; |
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103 DES_encrypt1((DES_LONG *)ti,schedule,DES_ENCRYPT); |
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104 c2ln(in,d0,d1,n); |
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105 in+=n; |
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106 d0^=ti[0]; |
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107 d1^=ti[1]; |
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108 l2cn(d0,d1,out,n); |
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109 out+=n; |
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110 /* 30-08-94 - eay - changed because l>>32 and |
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111 * l<<32 are bad under gcc :-( */ |
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112 if (numbits == 32) |
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113 { v0=v1; v1=d0; } |
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114 else if (numbits == 64) |
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115 { v0=d0; v1=d1; } |
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116 else |
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117 { |
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118 #ifndef L_ENDIAN |
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119 iv=&ovec[0]; |
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120 l2c(v0,iv); |
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121 l2c(v1,iv); |
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122 l2c(d0,iv); |
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123 l2c(d1,iv); |
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124 #else |
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125 sh[0]=v0, sh[1]=v1, sh[2]=d0, sh[3]=d1; |
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126 #endif |
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127 if (rem==0) |
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128 memmove(ovec,ovec+num,8); |
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129 else |
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130 for(i=0 ; i < 8 ; ++i) |
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131 ovec[i]=ovec[i+num]<<rem | |
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132 ovec[i+num+1]>>(8-rem); |
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133 #ifdef L_ENDIAN |
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134 v0=sh[0], v1=sh[1]; |
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135 #else |
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136 iv=&ovec[0]; |
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137 c2l(iv,v0); |
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138 c2l(iv,v1); |
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139 #endif |
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140 } |
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141 } |
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142 } |
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143 else |
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144 { |
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145 while (l >= (unsigned long)n) |
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146 { |
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147 l-=n; |
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148 ti[0]=v0; |
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149 ti[1]=v1; |
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150 DES_encrypt1((DES_LONG *)ti,schedule,DES_ENCRYPT); |
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151 c2ln(in,d0,d1,n); |
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152 in+=n; |
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153 /* 30-08-94 - eay - changed because l>>32 and |
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154 * l<<32 are bad under gcc :-( */ |
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155 if (numbits == 32) |
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156 { v0=v1; v1=d0; } |
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157 else if (numbits == 64) |
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158 { v0=d0; v1=d1; } |
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159 else |
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160 { |
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161 #ifndef L_ENDIAN |
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162 iv=&ovec[0]; |
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163 l2c(v0,iv); |
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164 l2c(v1,iv); |
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165 l2c(d0,iv); |
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166 l2c(d1,iv); |
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167 #else |
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168 sh[0]=v0, sh[1]=v1, sh[2]=d0, sh[3]=d1; |
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169 #endif |
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170 if (rem==0) |
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171 memmove(ovec,ovec+num,8); |
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172 else |
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173 for(i=0 ; i < 8 ; ++i) |
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174 ovec[i]=ovec[i+num]<<rem | |
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175 ovec[i+num+1]>>(8-rem); |
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176 #ifdef L_ENDIAN |
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177 v0=sh[0], v1=sh[1]; |
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178 #else |
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179 iv=&ovec[0]; |
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180 c2l(iv,v0); |
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181 c2l(iv,v1); |
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182 #endif |
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183 } |
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184 d0^=ti[0]; |
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185 d1^=ti[1]; |
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186 l2cn(d0,d1,out,n); |
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187 out+=n; |
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188 } |
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189 } |
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190 iv = &(*ivec)[0]; |
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191 l2c(v0,iv); |
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192 l2c(v1,iv); |
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193 v0=v1=d0=d1=ti[0]=ti[1]=0; |
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194 } |
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195 |