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      1 /*
      2  * AES (Rijndael) cipher - encrypt
      3  *
      4  * Modifications to public domain implementation:
      5  * - support only 128-bit keys
      6  * - cleanup
      7  * - use C pre-processor to make it easier to change S table access
      8  * - added option (AES_SMALL_TABLES) for reducing code size by about 8 kB at
      9  *   cost of reduced throughput (quite small difference on Pentium 4,
     10  *   10-25% when using -O1 or -O2 optimization)
     11  *
     12  * Copyright (c) 2003-2005, Jouni Malinen <j (at) w1.fi>
     13  *
     14  * This software may be distributed under the terms of the BSD license.
     15  * See README for more details.
     16  */
     17 
     18 #include "includes.h"
     19 
     20 #include "common.h"
     21 #include "crypto.h"
     22 #include "aes_i.h"
     23 
     24 static void rijndaelEncrypt(const u32 rk[/*44*/], const u8 pt[16], u8 ct[16])
     25 {
     26 	u32 s0, s1, s2, s3, t0, t1, t2, t3;
     27 	const int Nr = 10;
     28 #ifndef FULL_UNROLL
     29 	int r;
     30 #endif /* ?FULL_UNROLL */
     31 
     32 	/*
     33 	 * map byte array block to cipher state
     34 	 * and add initial round key:
     35 	 */
     36 	s0 = GETU32(pt     ) ^ rk[0];
     37 	s1 = GETU32(pt +  4) ^ rk[1];
     38 	s2 = GETU32(pt +  8) ^ rk[2];
     39 	s3 = GETU32(pt + 12) ^ rk[3];
     40 
     41 #define ROUND(i,d,s) \
     42 d##0 = TE0(s##0) ^ TE1(s##1) ^ TE2(s##2) ^ TE3(s##3) ^ rk[4 * i]; \
     43 d##1 = TE0(s##1) ^ TE1(s##2) ^ TE2(s##3) ^ TE3(s##0) ^ rk[4 * i + 1]; \
     44 d##2 = TE0(s##2) ^ TE1(s##3) ^ TE2(s##0) ^ TE3(s##1) ^ rk[4 * i + 2]; \
     45 d##3 = TE0(s##3) ^ TE1(s##0) ^ TE2(s##1) ^ TE3(s##2) ^ rk[4 * i + 3]
     46 
     47 #ifdef FULL_UNROLL
     48 
     49 	ROUND(1,t,s);
     50 	ROUND(2,s,t);
     51 	ROUND(3,t,s);
     52 	ROUND(4,s,t);
     53 	ROUND(5,t,s);
     54 	ROUND(6,s,t);
     55 	ROUND(7,t,s);
     56 	ROUND(8,s,t);
     57 	ROUND(9,t,s);
     58 
     59 	rk += Nr << 2;
     60 
     61 #else  /* !FULL_UNROLL */
     62 
     63 	/* Nr - 1 full rounds: */
     64 	r = Nr >> 1;
     65 	for (;;) {
     66 		ROUND(1,t,s);
     67 		rk += 8;
     68 		if (--r == 0)
     69 			break;
     70 		ROUND(0,s,t);
     71 	}
     72 
     73 #endif /* ?FULL_UNROLL */
     74 
     75 #undef ROUND
     76 
     77 	/*
     78 	 * apply last round and
     79 	 * map cipher state to byte array block:
     80 	 */
     81 	s0 = TE41(t0) ^ TE42(t1) ^ TE43(t2) ^ TE44(t3) ^ rk[0];
     82 	PUTU32(ct     , s0);
     83 	s1 = TE41(t1) ^ TE42(t2) ^ TE43(t3) ^ TE44(t0) ^ rk[1];
     84 	PUTU32(ct +  4, s1);
     85 	s2 = TE41(t2) ^ TE42(t3) ^ TE43(t0) ^ TE44(t1) ^ rk[2];
     86 	PUTU32(ct +  8, s2);
     87 	s3 = TE41(t3) ^ TE42(t0) ^ TE43(t1) ^ TE44(t2) ^ rk[3];
     88 	PUTU32(ct + 12, s3);
     89 }
     90 
     91 
     92 void * aes_encrypt_init(const u8 *key, size_t len)
     93 {
     94 	u32 *rk;
     95 	if (len != 16)
     96 		return NULL;
     97 	rk = os_malloc(AES_PRIV_SIZE);
     98 	if (rk == NULL)
     99 		return NULL;
    100 	rijndaelKeySetupEnc(rk, key);
    101 	return rk;
    102 }
    103 
    104 
    105 void aes_encrypt(void *ctx, const u8 *plain, u8 *crypt)
    106 {
    107 	rijndaelEncrypt(ctx, plain, crypt);
    108 }
    109 
    110 
    111 void aes_encrypt_deinit(void *ctx)
    112 {
    113 	os_memset(ctx, 0, AES_PRIV_SIZE);
    114 	os_free(ctx);
    115 }
    116