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      1 /*
      2  * AES (Rijndael) cipher - encrypt
      3  *
      4  * Modifications to public domain implementation:
      5  * - cleanup
      6  * - use C pre-processor to make it easier to change S table access
      7  * - added option (AES_SMALL_TABLES) for reducing code size by about 8 kB at
      8  *   cost of reduced throughput (quite small difference on Pentium 4,
      9  *   10-25% when using -O1 or -O2 optimization)
     10  *
     11  * Copyright (c) 2003-2012, Jouni Malinen <j (at) w1.fi>
     12  *
     13  * This software may be distributed under the terms of the BSD license.
     14  * See README for more details.
     15  */
     16 
     17 #include "includes.h"
     18 
     19 #include "common.h"
     20 #include "crypto.h"
     21 #include "aes_i.h"
     22 
     23 static void rijndaelEncrypt(const u32 rk[], int Nr, const u8 pt[16], u8 ct[16])
     24 {
     25 	u32 s0, s1, s2, s3, t0, t1, t2, t3;
     26 #ifndef FULL_UNROLL
     27 	int r;
     28 #endif /* ?FULL_UNROLL */
     29 
     30 	/*
     31 	 * map byte array block to cipher state
     32 	 * and add initial round key:
     33 	 */
     34 	s0 = GETU32(pt     ) ^ rk[0];
     35 	s1 = GETU32(pt +  4) ^ rk[1];
     36 	s2 = GETU32(pt +  8) ^ rk[2];
     37 	s3 = GETU32(pt + 12) ^ rk[3];
     38 
     39 #define ROUND(i,d,s) \
     40 d##0 = TE0(s##0) ^ TE1(s##1) ^ TE2(s##2) ^ TE3(s##3) ^ rk[4 * i]; \
     41 d##1 = TE0(s##1) ^ TE1(s##2) ^ TE2(s##3) ^ TE3(s##0) ^ rk[4 * i + 1]; \
     42 d##2 = TE0(s##2) ^ TE1(s##3) ^ TE2(s##0) ^ TE3(s##1) ^ rk[4 * i + 2]; \
     43 d##3 = TE0(s##3) ^ TE1(s##0) ^ TE2(s##1) ^ TE3(s##2) ^ rk[4 * i + 3]
     44 
     45 #ifdef FULL_UNROLL
     46 
     47 	ROUND(1,t,s);
     48 	ROUND(2,s,t);
     49 	ROUND(3,t,s);
     50 	ROUND(4,s,t);
     51 	ROUND(5,t,s);
     52 	ROUND(6,s,t);
     53 	ROUND(7,t,s);
     54 	ROUND(8,s,t);
     55 	ROUND(9,t,s);
     56 	if (Nr > 10) {
     57 		ROUND(10,s,t);
     58 		ROUND(11,t,s);
     59 		if (Nr > 12) {
     60 			ROUND(12,s,t);
     61 			ROUND(13,t,s);
     62 		}
     63 	}
     64 
     65 	rk += Nr << 2;
     66 
     67 #else  /* !FULL_UNROLL */
     68 
     69 	/* Nr - 1 full rounds: */
     70 	r = Nr >> 1;
     71 	for (;;) {
     72 		ROUND(1,t,s);
     73 		rk += 8;
     74 		if (--r == 0)
     75 			break;
     76 		ROUND(0,s,t);
     77 	}
     78 
     79 #endif /* ?FULL_UNROLL */
     80 
     81 #undef ROUND
     82 
     83 	/*
     84 	 * apply last round and
     85 	 * map cipher state to byte array block:
     86 	 */
     87 	s0 = TE41(t0) ^ TE42(t1) ^ TE43(t2) ^ TE44(t3) ^ rk[0];
     88 	PUTU32(ct     , s0);
     89 	s1 = TE41(t1) ^ TE42(t2) ^ TE43(t3) ^ TE44(t0) ^ rk[1];
     90 	PUTU32(ct +  4, s1);
     91 	s2 = TE41(t2) ^ TE42(t3) ^ TE43(t0) ^ TE44(t1) ^ rk[2];
     92 	PUTU32(ct +  8, s2);
     93 	s3 = TE41(t3) ^ TE42(t0) ^ TE43(t1) ^ TE44(t2) ^ rk[3];
     94 	PUTU32(ct + 12, s3);
     95 }
     96 
     97 
     98 void * aes_encrypt_init(const u8 *key, size_t len)
     99 {
    100 	u32 *rk;
    101 	int res;
    102 	rk = os_malloc(AES_PRIV_SIZE);
    103 	if (rk == NULL)
    104 		return NULL;
    105 	res = rijndaelKeySetupEnc(rk, key, len * 8);
    106 	if (res < 0) {
    107 		os_free(rk);
    108 		return NULL;
    109 	}
    110 	rk[AES_PRIV_NR_POS] = res;
    111 	return rk;
    112 }
    113 
    114 
    115 int aes_encrypt(void *ctx, const u8 *plain, u8 *crypt)
    116 {
    117 	u32 *rk = ctx;
    118 	rijndaelEncrypt(ctx, rk[AES_PRIV_NR_POS], plain, crypt);
    119 	return 0;
    120 }
    121 
    122 
    123 void aes_encrypt_deinit(void *ctx)
    124 {
    125 	os_memset(ctx, 0, AES_PRIV_SIZE);
    126 	os_free(ctx);
    127 }
    128