507 lines
12 KiB
Plaintext
507 lines
12 KiB
Plaintext
/* Rijndael Cipher
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Written by Mike Scott 21st April 1999
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Copyright (c) 1999 Mike Scott
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See rijndael documentation
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Permission for free direct or derivative use is granted subject
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to compliance with any conditions that the originators of the
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algorithm place on its exploitation.
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Inspiration from Brian Gladman's implementation is acknowledged.
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Written for clarity, rather than speed.
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Full implementation.
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Endian indifferent.
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*/
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/* modified in order to use the libmcrypt API by Nikos Mavroyanopoulos
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* All modifications are placed under the license of libmcrypt.
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*/
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/* $Id: rijndael-256.c,v 1.1 2007/07/19 06:11:48 pizon Exp $ */
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#include <libdefs.h>
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#include <mcrypt_modules.h>
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#include "rijndael.h"
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#define _mcrypt_set_key rijndael_256_LTX__mcrypt_set_key
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#define _mcrypt_encrypt rijndael_256_LTX__mcrypt_encrypt
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#define _mcrypt_decrypt rijndael_256_LTX__mcrypt_decrypt
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#define _mcrypt_get_size rijndael_256_LTX__mcrypt_get_size
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#define _mcrypt_get_block_size rijndael_256_LTX__mcrypt_get_block_size
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#define _is_block_algorithm rijndael_256_LTX__is_block_algorithm
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#define _mcrypt_get_key_size rijndael_256_LTX__mcrypt_get_key_size
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#define _mcrypt_get_supported_key_sizes rijndael_256_LTX__mcrypt_get_supported_key_sizes
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#define _mcrypt_get_algorithms_name rijndael_256_LTX__mcrypt_get_algorithms_name
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#define _mcrypt_self_test rijndael_256_LTX__mcrypt_self_test
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#define _mcrypt_algorithm_version rijndael_256_LTX__mcrypt_algorithm_version
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/* rotates x one bit to the left */
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#define ROTL(x) (((x)>>7)|((x)<<1))
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/* Rotates 32-bit word left by 1, 2 or 3 byte */
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#define ROTL8(x) (((x)<<8)|((x)>>24))
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#define ROTL16(x) (((x)<<16)|((x)>>16))
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#define ROTL24(x) (((x)<<24)|((x)>>8))
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/* Fixed Data */
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static byte InCo[4] = { 0xB, 0xD, 0x9, 0xE }; /* Inverse Coefficients */
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static byte fbsub[256];
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static byte rbsub[256];
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static byte ptab[256], ltab[256];
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static word32 ftable[256];
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static word32 rtable[256];
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static word32 rco[30];
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static int tables_ok = 0;
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/* Parameter-dependent data */
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/* in "rijndael.h" */
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static word32 pack(byte * b)
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{ /* pack bytes into a 32-bit Word */
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return ((word32) b[3] << 24) | ((word32) b[2] << 16) | ((word32)
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b[1] << 8)
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| (word32) b[0];
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}
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static void unpack(word32 a, byte * b)
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{ /* unpack bytes from a word */
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b[0] = (byte) a;
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b[1] = (byte) (a >> 8);
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b[2] = (byte) (a >> 16);
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b[3] = (byte) (a >> 24);
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}
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static byte xtime(byte a)
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{
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byte b;
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if (a & 0x80)
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b = 0x1B;
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else
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b = 0;
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a <<= 1;
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a ^= b;
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return a;
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}
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static byte bmul(byte x, byte y)
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{ /* x.y= AntiLog(Log(x) + Log(y)) */
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if (x && y)
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return ptab[(ltab[x] + ltab[y]) % 255];
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else
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return 0;
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}
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static word32 SubByte(word32 a)
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{
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byte b[4];
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unpack(a, b);
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b[0] = fbsub[b[0]];
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b[1] = fbsub[b[1]];
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b[2] = fbsub[b[2]];
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b[3] = fbsub[b[3]];
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return pack(b);
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}
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static byte product(word32 x, word32 y)
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{ /* dot product of two 4-byte arrays */
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byte xb[4], yb[4];
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unpack(x, xb);
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unpack(y, yb);
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return bmul(xb[0], yb[0]) ^ bmul(xb[1], yb[1]) ^ bmul(xb[2],
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yb[2]) ^
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bmul(xb[3], yb[3]);
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}
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static word32 InvMixCol(word32 x)
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{ /* matrix Multiplication */
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word32 y, m;
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byte b[4];
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m = pack(InCo);
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b[3] = product(m, x);
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m = ROTL24(m);
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b[2] = product(m, x);
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m = ROTL24(m);
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b[1] = product(m, x);
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m = ROTL24(m);
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b[0] = product(m, x);
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y = pack(b);
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return y;
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}
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static byte ByteSub(byte x)
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{
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byte y = ptab[255 - ltab[x]]; /* multiplicative inverse */
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x = y;
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x = ROTL(x);
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y ^= x;
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x = ROTL(x);
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y ^= x;
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x = ROTL(x);
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y ^= x;
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x = ROTL(x);
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y ^= x;
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y ^= 0x63;
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return y;
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}
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static void _mcrypt_rijndael_gentables(void)
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{ /* generate tables */
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int i;
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byte y, b[4];
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/* use 3 as primitive root to generate power and log tables */
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ltab[0] = 0;
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ptab[0] = 1;
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ltab[1] = 0;
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ptab[1] = 3;
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ltab[3] = 1;
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for (i = 2; i < 256; i++) {
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ptab[i] = ptab[i - 1] ^ xtime(ptab[i - 1]);
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ltab[ptab[i]] = i;
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}
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/* affine transformation:- each bit is xored with itself shifted one bit */
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fbsub[0] = 0x63;
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rbsub[0x63] = 0;
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for (i = 1; i < 256; i++) {
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y = ByteSub((byte) i);
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fbsub[i] = y;
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rbsub[y] = i;
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}
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for (i = 0, y = 1; i < 30; i++) {
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rco[i] = y;
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y = xtime(y);
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}
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/* calculate forward and reverse tables */
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for (i = 0; i < 256; i++) {
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y = fbsub[i];
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b[3] = y ^ xtime(y);
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b[2] = y;
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b[1] = y;
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b[0] = xtime(y);
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ftable[i] = pack(b);
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y = rbsub[i];
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b[3] = bmul(InCo[0], y);
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b[2] = bmul(InCo[1], y);
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b[1] = bmul(InCo[2], y);
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b[0] = bmul(InCo[3], y);
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rtable[i] = pack(b);
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}
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}
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WIN32DLL_DEFINE int _mcrypt_set_key(RI * rinst, byte * key, int nk)
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{ /* blocksize=32*nb bits. Key=32*nk bits */
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/* currently nb,bk = 4, 6 or 8 */
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/* key comes as 4*rinst->Nk bytes */
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/* Key Scheduler. Create expanded encryption key */
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int nb = 8; /* 256 block size */
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int i, j, k, m, N;
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int C1, C2, C3;
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word32 CipherKey[8];
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nk /= 4;
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if (tables_ok == 0) {
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_mcrypt_rijndael_gentables();
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tables_ok = 1;
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}
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rinst->Nb = nb;
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rinst->Nk = nk;
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/* rinst->Nr is number of rounds */
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if (rinst->Nb >= rinst->Nk)
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rinst->Nr = 6 + rinst->Nb;
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else
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rinst->Nr = 6 + rinst->Nk;
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C1 = 1;
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if (rinst->Nb < 8) {
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C2 = 2;
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C3 = 3;
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} else {
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C2 = 3;
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C3 = 4;
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}
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/* pre-calculate forward and reverse increments */
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for (m = j = 0; j < nb; j++, m += 3) {
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rinst->fi[m] = (j + C1) % nb;
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rinst->fi[m + 1] = (j + C2) % nb;
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rinst->fi[m + 2] = (j + C3) % nb;
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rinst->ri[m] = (nb + j - C1) % nb;
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rinst->ri[m + 1] = (nb + j - C2) % nb;
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rinst->ri[m + 2] = (nb + j - C3) % nb;
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}
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N = rinst->Nb * (rinst->Nr + 1);
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for (i = j = 0; i < rinst->Nk; i++, j += 4) {
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CipherKey[i] = pack(&key[j]);
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}
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for (i = 0; i < rinst->Nk; i++)
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rinst->fkey[i] = CipherKey[i];
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for (j = rinst->Nk, k = 0; j < N; j += rinst->Nk, k++) {
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rinst->fkey[j] =
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rinst->fkey[j -
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rinst->Nk] ^ SubByte(ROTL24(rinst->
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fkey[j -
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1])) ^
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rco[k];
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if (rinst->Nk <= 6) {
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for (i = 1; i < rinst->Nk && (i + j) < N; i++)
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rinst->fkey[i + j] =
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rinst->fkey[i + j -
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rinst->Nk] ^ rinst->
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fkey[i + j - 1];
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} else {
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for (i = 1; i < 4 && (i + j) < N; i++)
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rinst->fkey[i + j] =
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rinst->fkey[i + j -
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rinst->Nk] ^ rinst->
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fkey[i + j - 1];
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if ((j + 4) < N)
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rinst->fkey[j + 4] =
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rinst->fkey[j + 4 -
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rinst->
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Nk] ^ SubByte(rinst->
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fkey[j + 3]);
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for (i = 5; i < rinst->Nk && (i + j) < N; i++)
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rinst->fkey[i + j] =
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rinst->fkey[i + j -
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rinst->Nk] ^ rinst->
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fkey[i + j - 1];
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}
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}
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/* now for the expanded decrypt key in reverse order */
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for (j = 0; j < rinst->Nb; j++)
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rinst->rkey[j + N - rinst->Nb] = rinst->fkey[j];
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for (i = rinst->Nb; i < N - rinst->Nb; i += rinst->Nb) {
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k = N - rinst->Nb - i;
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for (j = 0; j < rinst->Nb; j++)
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rinst->rkey[k + j] = InvMixCol(rinst->fkey[i + j]);
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}
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for (j = N - rinst->Nb; j < N; j++)
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rinst->rkey[j - N + rinst->Nb] = rinst->fkey[j];
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return 0;
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}
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/* There is an obvious time/space trade-off possible here. *
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* Instead of just one ftable[], I could have 4, the other *
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* 3 pre-rotated to save the ROTL8, ROTL16 and ROTL24 overhead */
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WIN32DLL_DEFINE void _mcrypt_encrypt(RI * rinst, byte * buff)
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{
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int i, j, k, m;
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word32 a[8], b[8], *x, *y, *t;
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for (i = j = 0; i < rinst->Nb; i++, j += 4) {
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a[i] = pack(&buff[j]);
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a[i] ^= rinst->fkey[i];
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}
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k = rinst->Nb;
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x = a;
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y = b;
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/* State alternates between a and b */
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for (i = 1; i < rinst->Nr; i++) { /* rinst->Nr is number of rounds. May be odd. */
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/* if rinst->Nb is fixed - unroll this next
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loop and hard-code in the values of fi[] */
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for (m = j = 0; j < rinst->Nb; j++, m += 3) { /* deal with each 32-bit element of the State */
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/* This is the time-critical bit */
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y[j] = rinst->fkey[k++] ^ ftable[(byte) x[j]] ^
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ROTL8(ftable[(byte) (x[rinst->fi[m]] >> 8)]) ^
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ROTL16(ftable
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[(byte) (x[rinst->fi[m + 1]] >> 16)]) ^
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ROTL24(ftable[x[rinst->fi[m + 2]] >> 24]);
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}
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t = x;
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x = y;
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y = t; /* swap pointers */
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}
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/* Last Round - unroll if possible */
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for (m = j = 0; j < rinst->Nb; j++, m += 3) {
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y[j] = rinst->fkey[k++] ^ (word32) fbsub[(byte) x[j]] ^
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ROTL8((word32) fbsub[(byte) (x[rinst->fi[m]] >> 8)]) ^
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ROTL16((word32)
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fbsub[(byte) (x[rinst->fi[m + 1]] >> 16)]) ^
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ROTL24((word32) fbsub[x[rinst->fi[m + 2]] >> 24]);
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}
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for (i = j = 0; i < rinst->Nb; i++, j += 4) {
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unpack(y[i], &buff[j]);
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x[i] = y[i] = 0; /* clean up stack */
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}
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return;
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}
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WIN32DLL_DEFINE void _mcrypt_decrypt(RI * rinst, byte * buff)
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{
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int i, j, k, m;
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word32 a[8], b[8], *x, *y, *t;
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for (i = j = 0; i < rinst->Nb; i++, j += 4) {
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a[i] = pack(&buff[j]);
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a[i] ^= rinst->rkey[i];
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}
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k = rinst->Nb;
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x = a;
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y = b;
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/* State alternates between a and b */
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for (i = 1; i < rinst->Nr; i++) { /* rinst->Nr is number of rounds. May be odd. */
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/* if rinst->Nb is fixed - unroll this next
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loop and hard-code in the values of ri[] */
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for (m = j = 0; j < rinst->Nb; j++, m += 3) { /* This is the time-critical bit */
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y[j] = rinst->rkey[k++] ^ rtable[(byte) x[j]] ^
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ROTL8(rtable[(byte) (x[rinst->ri[m]] >> 8)]) ^
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ROTL16(rtable
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[(byte) (x[rinst->ri[m + 1]] >> 16)]) ^
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ROTL24(rtable[x[rinst->ri[m + 2]] >> 24]);
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}
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t = x;
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x = y;
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y = t; /* swap pointers */
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}
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/* Last Round - unroll if possible */
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for (m = j = 0; j < rinst->Nb; j++, m += 3) {
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y[j] = rinst->rkey[k++] ^ (word32) rbsub[(byte) x[j]] ^
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ROTL8((word32) rbsub[(byte) (x[rinst->ri[m]] >> 8)]) ^
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ROTL16((word32)
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rbsub[(byte) (x[rinst->ri[m + 1]] >> 16)]) ^
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ROTL24((word32) rbsub[x[rinst->ri[m + 2]] >> 24]);
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}
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for (i = j = 0; i < rinst->Nb; i++, j += 4) {
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unpack(y[i], &buff[j]);
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x[i] = y[i] = 0; /* clean up stack */
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}
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return;
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}
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WIN32DLL_DEFINE int _mcrypt_get_size()
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{
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return sizeof(RI);
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}
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WIN32DLL_DEFINE int _mcrypt_get_block_size()
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{
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return 32;
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}
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WIN32DLL_DEFINE int _is_block_algorithm()
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{
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return 1;
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}
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WIN32DLL_DEFINE int _mcrypt_get_key_size()
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{
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return 32;
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}
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static const int key_sizes[] = { 16, 24, 32 };
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WIN32DLL_DEFINE const int *_mcrypt_get_supported_key_sizes(int *len)
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{
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*len = sizeof(key_sizes)/sizeof(int);
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return key_sizes;
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}
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WIN32DLL_DEFINE char *_mcrypt_get_algorithms_name()
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{
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return "Rijndael-256";
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}
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#define CIPHER "45af6c269326fd935edd24733cff74fc1aa358841a6cd80b79f242d983f8ff2e"
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WIN32DLL_DEFINE int _mcrypt_self_test()
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{
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char *keyword;
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unsigned char plaintext[32];
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unsigned char ciphertext[32];
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int blocksize = _mcrypt_get_block_size(), j;
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void *key;
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unsigned char cipher_tmp[200];
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keyword = calloc(1, _mcrypt_get_key_size());
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if (keyword == NULL)
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return -1;
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for (j = 0; j < _mcrypt_get_key_size(); j++) {
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keyword[j] = ((j * 2 + 10) % 256);
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}
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for (j = 0; j < blocksize; j++) {
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plaintext[j] = j % 256;
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}
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key = malloc(_mcrypt_get_size());
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if (key == NULL) {
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free(keyword);
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return -1;
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}
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memcpy(ciphertext, plaintext, blocksize);
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_mcrypt_set_key(key, (void *) keyword, _mcrypt_get_key_size());
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free(keyword);
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_mcrypt_encrypt(key, (void *) ciphertext);
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for (j = 0; j < blocksize; j++) {
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sprintf(&((char *) cipher_tmp)[2 * j], "%.2x",
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ciphertext[j]);
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}
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if (strcmp((char *) cipher_tmp, CIPHER) != 0) {
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printf("failed compatibility\n");
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printf("Expected: %s\nGot: %s\n", CIPHER,
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(char *) cipher_tmp);
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free(key);
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return -1;
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}
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_mcrypt_decrypt(key, (void *) ciphertext);
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free(key);
|
|
|
|
if (strcmp(ciphertext, plaintext) != 0) {
|
|
printf("failed internally\n");
|
|
return -1;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
WIN32DLL_DEFINE word32 _mcrypt_algorithm_version()
|
|
{
|
|
return 20010801;
|
|
}
|
|
|
|
#ifdef WIN32
|
|
# ifdef USE_LTDL
|
|
WIN32DLL_DEFINE int main (void)
|
|
{
|
|
/* empty main function to avoid linker error (see cygwin FAQ) */
|
|
}
|
|
# endif
|
|
#endif
|