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POmacos: CCCrypt() decrypt output does not match original plaintext
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  1. POmacos: CCCrypt() decrypt output does not match original plaintext
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    copied!<p>In the code below, the decrypted text does not match the original plaintext. The first 12 bytes are messed up. Note that block cipher padding has been disabled. I have tried different values for BUF_SIZE, all multiples of 16 - every time the first 12 bytes of the decrypted data is wrong. Here's the output:</p> <pre><code> plain buf[32]: 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 11 outlen=32 outlen=32 dec buf[32]: 0C 08 01 46 6D 3D FC E9 98 0A 2D E1 AF A3 95 3A 0B 31 1B 9D 11 11 11 11 11 11 11 11 11 11 11 11 </code></pre> <p>Here's the code:</p> <pre><code>#include &lt;stdio.h&gt; #include &lt;string.h&gt; #include &lt;CommonCrypto/CommonCryptor.h&gt; static void dumpbuf(const char* label, const unsigned char* pkt, unsigned int len) { const int bytesPerLine = 16; if (label) { printf("%s[%d]:\n", label, len); } for (int i = 0; i &lt; int(len); i++) { if (i &amp;&amp; ((i % bytesPerLine) == 0)) { printf("\n"); } unsigned int c = (unsigned int)pkt[i] &amp; 0xFFu; printf("%02X ", c); } printf("\n"); } int main(int argc, char* argv[]) { unsigned char key[16]; unsigned char iv[16]; memset(key, 0x22, sizeof(key)); memset(iv, 0x33, sizeof(iv)); #define BUF_SIZE 32 unsigned char plainBuf[BUF_SIZE]; unsigned char encBuf[BUF_SIZE]; memset(plainBuf, 0x11, sizeof(plainBuf)); dumpbuf("plain buf", plainBuf, sizeof(plainBuf)); int outlen; CCCryptorStatus status; status = CCCrypt(kCCEncrypt, kCCAlgorithmAES128, 0, key, kCCKeySizeAES128, iv, plainBuf, sizeof(plainBuf), encBuf, sizeof(encBuf), (size_t*)&amp;outlen); if (kCCSuccess != status) { fprintf(stderr, "FEcipher: CCCrypt failure\n"); return -1; } printf("outlen=%d\n", outlen); status = CCCrypt(kCCDecrypt, kCCAlgorithmAES128, 0, key, kCCKeySizeAES128, iv, encBuf, sizeof(encBuf), plainBuf, sizeof(plainBuf), (size_t*)&amp;outlen); if (kCCSuccess != status) { fprintf(stderr, "FEcipher: CCCrypt failure\n"); return -1; } printf("outlen=%d\n", outlen); dumpbuf("dec buf", plainBuf, sizeof(plainBuf)); return 0; } </code></pre> <p>Thanks, Hari</p>
 

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