crypto/heimdal/doc/doxyout/hcrypto/html/example__evp__cipher_8c-example.html

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  22 <h1>example_evp_cipher.c</h1>This is an example how to use <a class="el" href="group__hcrypto__evp.html#g98da5a5c1aa25d9cb2e4717fa11314bd">EVP_CipherInit_ex()</a>, <a class="el" href="group__hcrypto__evp.html#g863349e1001b36cfd6c4afedddd12862">EVP_CipherUpdate()</a> and <a class="el" href="group__hcrypto__evp.html#g714eef7d737fd68171d852043a4995de">EVP_CipherFinal_ex()</a>.<p>
  23 <div class="fragment"><pre class="fragment"><span class="comment">/*</span>
  24 <span class="comment"> * Copyright (c) 2008 Kungliga Tekniska Högskolan</span>
  25 <span class="comment"> * (Royal Institute of Technology, Stockholm, Sweden).</span>
  26 <span class="comment"> * All rights reserved.</span>
  27 <span class="comment"> *</span>
  28 <span class="comment"> * Redistribution and use in source and binary forms, with or without</span>
  29 <span class="comment"> * modification, are permitted provided that the following conditions</span>
  30 <span class="comment"> * are met:</span>
  31 <span class="comment"> *</span>
  32 <span class="comment"> * 1. Redistributions of source code must retain the above copyright</span>
  33 <span class="comment"> *    notice, this list of conditions and the following disclaimer.</span>
  34 <span class="comment"> *</span>
  35 <span class="comment"> * 2. Redistributions in binary form must reproduce the above copyright</span>
  36 <span class="comment"> *    notice, this list of conditions and the following disclaimer in the</span>
  37 <span class="comment"> *    documentation and/or other materials provided with the distribution.</span>
  38 <span class="comment"> *</span>
  39 <span class="comment"> * 3. Neither the name of the Institute nor the names of its contributors</span>
  40 <span class="comment"> *    may be used to endorse or promote products derived from this software</span>
  41 <span class="comment"> *    without specific prior written permission.</span>
  42 <span class="comment"> *</span>
  43 <span class="comment"> * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND</span>
  44 <span class="comment"> * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE</span>
  45 <span class="comment"> * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE</span>
  46 <span class="comment"> * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE</span>
  47 <span class="comment"> * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL</span>
  48 <span class="comment"> * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS</span>
  49 <span class="comment"> * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)</span>
  50 <span class="comment"> * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT</span>
  51 <span class="comment"> * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY</span>
  52 <span class="comment"> * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF</span>
  53 <span class="comment"> * SUCH DAMAGE.</span>
  54 <span class="comment"> */</span>
  55
  56 <span class="preprocessor">#include &lt;krb5-types.h&gt;</span> <span class="comment">/* should really be stdint.h */</span>
  57 <span class="preprocessor">#include &lt;hcrypto/evp.h&gt;</span>
  58
  59 <span class="preprocessor">#include &lt;stdio.h&gt;</span>
  60 <span class="preprocessor">#include &lt;stdlib.h&gt;</span>
  61 <span class="preprocessor">#include &lt;string.h&gt;</span>
  62 <span class="preprocessor">#include &lt;err.h&gt;</span>
  63 <span class="preprocessor">#include &lt;assert.h&gt;</span>
  64
  65 <span class="preprocessor">#include "roken.h"</span>
  66
  67 <span class="comment">/* key and initial vector */</span>
  68 <span class="keyword">static</span> <span class="keywordtype">char</span> key[16] =
  69     <span class="stringliteral">"\xaa\xbb\x45\xd4\xaa\xbb\x45\xd4"</span>
  70     <span class="stringliteral">"\xaa\xbb\x45\xd4\xaa\xbb\x45\xd4"</span>;
  71 <span class="keyword">static</span> <span class="keywordtype">char</span> ivec[16] =
  72     <span class="stringliteral">"\xaa\xbb\x45\xd4\xaa\xbb\x45\xd4"</span>
  73     <span class="stringliteral">"\xaa\xbb\x45\xd4\xaa\xbb\x45\xd4"</span>;
  74
  75 <span class="keyword">static</span> <span class="keywordtype">void</span>
  76 usage(<span class="keywordtype">int</span> exit_code) __attribute__((noreturn));
  77
  78 <span class="keyword">static</span> <span class="keywordtype">void</span>
  79 usage(<span class="keywordtype">int</span> exit_code)
  80 {
  81     printf(<span class="stringliteral">"usage: %s in out\n"</span>, getprogname());
  82     exit(exit_code);
  83 }
  84
  85
  86 <span class="keywordtype">int</span>
  87 main(<span class="keywordtype">int</span> argc, <span class="keywordtype">char</span> **argv)
  88 {
  89     <span class="keywordtype">int</span> encryptp = 1;
  90     <span class="keyword">const</span> <span class="keywordtype">char</span> *ifn = NULL, *ofn = NULL;
  91     FILE *in, *out;
  92     <span class="keywordtype">void</span> *ibuf, *obuf;
  93     <span class="keywordtype">int</span> ilen, olen;
  94     <span class="keywordtype">size_t</span> block_size = 0;
  95     <span class="keyword">const</span> EVP_CIPHER *c = <a name="a0"></a><a class="code" href="group__hcrypto__evp.html#g2747bac943db15c97167ac37fdc2af43">EVP_aes_128_cbc</a>();
  96     EVP_CIPHER_CTX ctx;
  97     <span class="keywordtype">int</span> ret;
  98
  99     setprogname(argv[0]);
 100
 101     <span class="keywordflow">if</span> (argc == 2) {
 102         <span class="keywordflow">if</span> (strcmp(argv[1], <span class="stringliteral">"--version"</span>) == 0) {
 103             printf(<span class="stringliteral">"version"</span>);
 104             exit(0);
 105         }
 106         <span class="keywordflow">if</span> (strcmp(argv[1], <span class="stringliteral">"--help"</span>) == 0)
 107             usage(0);
 108         usage(1);
 109     } <span class="keywordflow">else</span> <span class="keywordflow">if</span> (argc == 4) {
 110         block_size = atoi(argv[1]);
 111         <span class="keywordflow">if</span> (block_size == 0)
 112             errx(1, <span class="stringliteral">"invalid blocksize %s"</span>, argv[1]);
 113         ifn = argv[2];
 114         ofn = argv[3];
 115     } <span class="keywordflow">else</span>
 116         usage(1);
 117
 118     in = fopen(ifn, <span class="stringliteral">"r"</span>);
 119     <span class="keywordflow">if</span> (in == NULL)
 120         errx(1, <span class="stringliteral">"failed to open input file"</span>);
 121     out = fopen(ofn, <span class="stringliteral">"w+"</span>);
 122     <span class="keywordflow">if</span> (out == NULL)
 123         errx(1, <span class="stringliteral">"failed to open output file"</span>);
 124
 125     <span class="comment">/* Check that key and ivec are long enough */</span>
 126     assert(<a name="a1"></a><a class="code" href="group__hcrypto__evp.html#g4793a9e130da86ac42c497b19395b748">EVP_CIPHER_key_length</a>(c) &lt;= <span class="keyword">sizeof</span>(key));
 127     assert(<a name="a2"></a><a class="code" href="group__hcrypto__evp.html#g7edebe76d19dee11686a6698d24f19f5">EVP_CIPHER_iv_length</a>(c) &lt;= <span class="keyword">sizeof</span>(ivec));
 128
 129     <span class="comment">/*</span>
 130 <span class="comment">     * Allocate buffer, the output buffer is at least</span>
 131 <span class="comment">     * EVP_CIPHER_block_size() longer</span>
 132 <span class="comment">     */</span>
 133     ibuf = malloc(block_size);
 134     obuf = malloc(block_size + <a name="a3"></a><a class="code" href="group__hcrypto__evp.html#g3123ff4b426783dd972538249b9e9d4d">EVP_CIPHER_block_size</a>(c));
 135
 136     <span class="comment">/*</span>
 137 <span class="comment">     * Init the memory used for EVP_CIPHER_CTX and set the key and</span>
 138 <span class="comment">     * ivec.</span>
 139 <span class="comment">     */</span>
 140     <a name="a4"></a><a class="code" href="group__hcrypto__evp.html#g13d0ff0e87312566cb6b3591157f9754">EVP_CIPHER_CTX_init</a>(&amp;ctx);
 141     <a name="a5"></a><a class="code" href="group__hcrypto__evp.html#g98da5a5c1aa25d9cb2e4717fa11314bd">EVP_CipherInit_ex</a>(&amp;ctx, c, NULL, key, ivec, encryptp);
 142
 143     <span class="comment">/* read in buffer */</span>
 144     <span class="keywordflow">while</span> ((ilen = fread(ibuf, 1, block_size, in)) &gt; 0) {
 145         <span class="comment">/* encrypto/decrypt */</span>
 146         ret = <a name="a6"></a><a class="code" href="group__hcrypto__evp.html#g863349e1001b36cfd6c4afedddd12862">EVP_CipherUpdate</a>(&amp;ctx, obuf, &amp;olen, ibuf, ilen);
 147         <span class="keywordflow">if</span> (ret != 1) {
 148             <a name="a7"></a><a class="code" href="group__hcrypto__evp.html#gc16dd3987cd90c8bcdbad5290c558359">EVP_CIPHER_CTX_cleanup</a>(&amp;ctx);
 149             errx(1, <span class="stringliteral">"EVP_CipherUpdate failed"</span>);
 150         }
 151         <span class="comment">/* write out to output file */</span>
 152         fwrite(obuf, 1, olen, out);
 153     }
 154     <span class="comment">/* done reading */</span>
 155     fclose(in);
 156
 157     <span class="comment">/* clear up any last bytes left in the output buffer */</span>
 158     ret = <a name="a8"></a><a class="code" href="group__hcrypto__evp.html#g714eef7d737fd68171d852043a4995de">EVP_CipherFinal_ex</a>(&amp;ctx, obuf, &amp;olen);
 159     <a class="code" href="group__hcrypto__evp.html#gc16dd3987cd90c8bcdbad5290c558359">EVP_CIPHER_CTX_cleanup</a>(&amp;ctx);
 160     <span class="keywordflow">if</span> (ret != 1)
 161         errx(1, <span class="stringliteral">"EVP_CipherFinal_ex failed"</span>);
 162
 163     <span class="comment">/* write the last bytes out and close */</span>
 164     fwrite(obuf, 1, olen, out);
 165     fclose(out);
 166
 167     <span class="keywordflow">return</span> 0;
 168 }
 169 </pre></div> </div>
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