networking/tls_aes.c - codeaurora/busybox - Gitiles

 /*
  * Copyright (C) 2017 Denys Vlasenko
  *
  * Licensed under GPLv2, see file LICENSE in this source tree.
  */

 /* This AES implementation is derived from tiny-AES128-C code,
  * which was put by its author into public domain:
  *
  * tiny-AES128-C/unlicense.txt, Dec 8, 2014
  * """
  * This is free and unencumbered software released into the public domain.
  *
  * Anyone is free to copy, modify, publish, use, compile, sell, or
  * distribute this software, either in source code form or as a compiled
  * binary, for any purpose, commercial or non-commercial, and by any
  * means.
  *
  * In jurisdictions that recognize copyright laws, the author or authors
  * of this software dedicate any and all copyright interest in the
  * software to the public domain. We make this dedication for the benefit
  * of the public at large and to the detriment of our heirs and
  * successors. We intend this dedication to be an overt act of
  * relinquishment in perpetuity of all present and future rights to this
  * software under copyright law.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
  * IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR
  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  * OTHER DEALINGS IN THE SOFTWARE.
  * """
  */
 /* Note that only original tiny-AES128-C code is public domain.
  * The derived code in this file has been expanded to also implement aes192
  * and aes256 and use more efficient word-sized operations in many places,
  * and put under GPLv2 license.
  */
 #include "tls.h"

 // The lookup-tables are marked const so they can be placed in read-only storage instead of RAM
 // The numbers below can be computed dynamically trading ROM for RAM -
 // This can be useful in (embedded) bootloader applications, where ROM is often limited.
 static const uint8_t sbox[] = {
 	0x63, 0x7c, 0x77, 0x7b, 0xf2, 0x6b, 0x6f, 0xc5,
 	0x30, 0x01, 0x67, 0x2b, 0xfe, 0xd7, 0xab, 0x76,
 	0xca, 0x82, 0xc9, 0x7d, 0xfa, 0x59, 0x47, 0xf0,
 	0xad, 0xd4, 0xa2, 0xaf, 0x9c, 0xa4, 0x72, 0xc0,
 	0xb7, 0xfd, 0x93, 0x26,	0x36, 0x3f, 0xf7, 0xcc,
 	0x34, 0xa5, 0xe5, 0xf1, 0x71, 0xd8, 0x31, 0x15,
 	0x04, 0xc7, 0x23, 0xc3, 0x18, 0x96, 0x05, 0x9a,
 	0x07, 0x12, 0x80, 0xe2,	0xeb, 0x27, 0xb2, 0x75,
 	0x09, 0x83, 0x2c, 0x1a, 0x1b, 0x6e, 0x5a, 0xa0,
 	0x52, 0x3b, 0xd6, 0xb3, 0x29, 0xe3, 0x2f, 0x84,
 	0x53, 0xd1, 0x00, 0xed,	0x20, 0xfc, 0xb1, 0x5b,
 	0x6a, 0xcb, 0xbe, 0x39, 0x4a, 0x4c, 0x58, 0xcf,
 	0xd0, 0xef, 0xaa, 0xfb, 0x43, 0x4d, 0x33, 0x85,
 	0x45, 0xf9, 0x02, 0x7f,	0x50, 0x3c, 0x9f, 0xa8,
 	0x51, 0xa3, 0x40, 0x8f, 0x92, 0x9d, 0x38, 0xf5,
 	0xbc, 0xb6, 0xda, 0x21, 0x10, 0xff, 0xf3, 0xd2,
 	0xcd, 0x0c, 0x13, 0xec,	0x5f, 0x97, 0x44, 0x17,
 	0xc4, 0xa7, 0x7e, 0x3d, 0x64, 0x5d, 0x19, 0x73,
 	0x60, 0x81, 0x4f, 0xdc, 0x22, 0x2a, 0x90, 0x88,
 	0x46, 0xee, 0xb8, 0x14,	0xde, 0x5e, 0x0b, 0xdb,
 	0xe0, 0x32, 0x3a, 0x0a, 0x49, 0x06, 0x24, 0x5c,
 	0xc2, 0xd3, 0xac, 0x62, 0x91, 0x95, 0xe4, 0x79,
 	0xe7, 0xc8, 0x37, 0x6d,	0x8d, 0xd5, 0x4e, 0xa9,
 	0x6c, 0x56, 0xf4, 0xea, 0x65, 0x7a, 0xae, 0x08,
 	0xba, 0x78, 0x25, 0x2e, 0x1c, 0xa6, 0xb4, 0xc6,
 	0xe8, 0xdd, 0x74, 0x1f,	0x4b, 0xbd, 0x8b, 0x8a,
 	0x70, 0x3e, 0xb5, 0x66, 0x48, 0x03, 0xf6, 0x0e,
 	0x61, 0x35, 0x57, 0xb9, 0x86, 0xc1, 0x1d, 0x9e,
 	0xe1, 0xf8, 0x98, 0x11,	0x69, 0xd9, 0x8e, 0x94,
 	0x9b, 0x1e, 0x87, 0xe9, 0xce, 0x55, 0x28, 0xdf,
 	0x8c, 0xa1, 0x89, 0x0d, 0xbf, 0xe6, 0x42, 0x68,
 	0x41, 0x99, 0x2d, 0x0f, 0xb0, 0x54, 0xbb, 0x16,
 };

 static const uint8_t rsbox[] = {
 	0x52, 0x09, 0x6a, 0xd5, 0x30, 0x36, 0xa5, 0x38,
 	0xbf, 0x40, 0xa3, 0x9e,	0x81, 0xf3, 0xd7, 0xfb,
 	0x7c, 0xe3, 0x39, 0x82,	0x9b, 0x2f, 0xff, 0x87,
 	0x34, 0x8e, 0x43, 0x44, 0xc4, 0xde, 0xe9, 0xcb,
 	0x54, 0x7b, 0x94, 0x32, 0xa6, 0xc2, 0x23, 0x3d,
 	0xee, 0x4c, 0x95, 0x0b,	0x42, 0xfa, 0xc3, 0x4e,
 	0x08, 0x2e, 0xa1, 0x66,	0x28, 0xd9, 0x24, 0xb2,
 	0x76, 0x5b, 0xa2, 0x49,	0x6d, 0x8b, 0xd1, 0x25,
 	0x72, 0xf8, 0xf6, 0x64, 0x86, 0x68, 0x98, 0x16,
 	0xd4, 0xa4, 0x5c, 0xcc, 0x5d, 0x65, 0xb6, 0x92,
 	0x6c, 0x70, 0x48, 0x50,	0xfd, 0xed, 0xb9, 0xda,
 	0x5e, 0x15, 0x46, 0x57, 0xa7, 0x8d, 0x9d, 0x84,
 	0x90, 0xd8, 0xab, 0x00, 0x8c, 0xbc, 0xd3, 0x0a,
 	0xf7, 0xe4, 0x58, 0x05, 0xb8, 0xb3, 0x45, 0x06,
 	0xd0, 0x2c, 0x1e, 0x8f, 0xca, 0x3f, 0x0f, 0x02,
 	0xc1, 0xaf, 0xbd, 0x03, 0x01, 0x13, 0x8a, 0x6b,
 	0x3a, 0x91, 0x11, 0x41,	0x4f, 0x67, 0xdc, 0xea,
 	0x97, 0xf2, 0xcf, 0xce, 0xf0, 0xb4, 0xe6, 0x73,
 	0x96, 0xac, 0x74, 0x22, 0xe7, 0xad, 0x35, 0x85,
 	0xe2, 0xf9, 0x37, 0xe8,	0x1c, 0x75, 0xdf, 0x6e,
 	0x47, 0xf1, 0x1a, 0x71, 0x1d, 0x29, 0xc5, 0x89,
 	0x6f, 0xb7, 0x62, 0x0e, 0xaa, 0x18, 0xbe, 0x1b,
 	0xfc, 0x56, 0x3e, 0x4b,	0xc6, 0xd2, 0x79, 0x20,
 	0x9a, 0xdb, 0xc0, 0xfe, 0x78, 0xcd, 0x5a, 0xf4,
 	0x1f, 0xdd, 0xa8, 0x33, 0x88, 0x07, 0xc7, 0x31,
 	0xb1, 0x12, 0x10, 0x59,	0x27, 0x80, 0xec, 0x5f,
 	0x60, 0x51, 0x7f, 0xa9, 0x19, 0xb5, 0x4a, 0x0d,
 	0x2d, 0xe5, 0x7a, 0x9f, 0x93, 0xc9, 0x9c, 0xef,
 	0xa0, 0xe0, 0x3b, 0x4d,	0xae, 0x2a, 0xf5, 0xb0,
 	0xc8, 0xeb, 0xbb, 0x3c,	0x83, 0x53, 0x99, 0x61,
 	0x17, 0x2b, 0x04, 0x7e,	0xba, 0x77, 0xd6, 0x26,
 	0xe1, 0x69, 0x14, 0x63,	0x55, 0x21, 0x0c, 0x7d,
 };

 // SubWord() is a function that takes a four-byte input word and
 // applies the S-box to each of the four bytes to produce an output word.
 static uint32_t Subword(uint32_t x)
 {
 	return (sbox[(x >> 24)      ] << 24)
 	|      (sbox[(x >> 16) & 255] << 16)
 	|      (sbox[(x >> 8 ) & 255] << 8 )
 	|      (sbox[(x      ) & 255]      );
 }

 // This function produces Nb(Nr+1) round keys.
 // The round keys are used in each round to decrypt the states.
 static int KeyExpansion(uint32_t *RoundKey, const void *key, unsigned key_len)
 {
 	// The round constant word array, Rcon[i], contains the values given by
 	// x to th e power (i-1) being powers of x (x is denoted as {02}) in the field GF(2^8).
 	// Note that i starts at 2, not 0.
 	static const uint8_t Rcon[] = {
 		0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36
 	//..... 0x6c, 0xd8, 0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc, 0x63, 0xc6,...
 	// but aes256 only uses values up to 0x36
 	};
 	int rounds, words_key, words_RoundKey;
 	int i, j, k;

 	// key_len 16: aes128, rounds 10, words_key 4, words_RoundKey 44
 	// key_len 24: aes192, rounds 12, words_key 6, words_RoundKey 52
 	// key_len 32: aes256, rounds 14, words_key 8, words_RoundKey 60
 	words_key = key_len / 4;
 	rounds = 6 + (key_len / 4);
 	words_RoundKey = 28 + key_len;

 	// The first round key is the key itself.
 	for (i = 0; i < words_key; i++)
 		RoundKey[i] = get_unaligned_be32((uint32_t*)key + i);
 	// i == words_key now

 	// All other round keys are found from the previous round keys.
 	j = k = 0;
 	for (; i < words_RoundKey; i++) {
 		uint32_t tempa;

 		tempa = RoundKey[i - 1];
 		if (j == 0) {
 			// RotWord(): rotates the 4 bytes in a word to the left once.
 			tempa = (tempa << 8) | (tempa >> 24);
 			tempa = Subword(tempa);
 			tempa ^= (uint32_t)Rcon[k] << 24;
 		} else if (words_key > 6 && j == 4) {
 			tempa = Subword(tempa);
 		}
 		RoundKey[i] = RoundKey[i - words_key] ^ tempa;
 		j++;
 		if (j == words_key) {
 			j = 0;
 			k++;
 		}
 	}
 	return rounds;
 }

 // This function adds the round key to state.
 // The round key is added to the state by an XOR function.
 static void AddRoundKey(unsigned astate[16], const uint32_t *RoundKeys)
 {
 	int i;

 	for (i = 0; i < 16; i += 4) {
 		uint32_t n = *RoundKeys++;
 		astate[i + 0] ^= (n >> 24);
 		astate[i + 1] ^= (n >> 16) & 255;
 		astate[i + 2] ^= (n >> 8) & 255;
 		astate[i + 3] ^= n & 255;
 	}
 }

 // The SubBytes Function Substitutes the values in the
 // state matrix with values in an S-box.
 static void SubBytes(unsigned astate[16])
 {
 	int i;

 	for (i = 0; i < 16; i++)
 		astate[i] = sbox[astate[i]];
 }

 // Our code actually stores "columns" (in aes encryption terminology)
 // of state in rows: first 4 elements are "row 0, col 0", "row 1, col 0".
 // "row 2, col 0", "row 3, col 0". The fifth element is "row 0, col 1",
 // and so on.
 #define ASTATE(col,row) astate[(col)*4 + (row)]

 // The ShiftRows() function shifts the rows in the state to the left.
 // Each row is shifted with different offset.
 // Offset = Row number. So the first row is not shifted.
 static void ShiftRows(unsigned astate[16])
 {
 	unsigned v;

 	// Rotate first row 1 columns to left
 	v = ASTATE(0,1);
 	ASTATE(0,1) = ASTATE(1,1);
 	ASTATE(1,1) = ASTATE(2,1);
 	ASTATE(2,1) = ASTATE(3,1);
 	ASTATE(3,1) = v;

 	// Rotate second row 2 columns to left
 	v = ASTATE(0,2); ASTATE(0,2) = ASTATE(2,2); ASTATE(2,2) = v;
 	v = ASTATE(1,2); ASTATE(1,2) = ASTATE(3,2); ASTATE(3,2) = v;

 	// Rotate third row 3 columns to left
 	v = ASTATE(3,3);
 	ASTATE(3,3) = ASTATE(2,3);
 	ASTATE(2,3) = ASTATE(1,3);
 	ASTATE(1,3) = ASTATE(0,3);
 	ASTATE(0,3) = v;
 }

 // MixColumns function mixes the columns of the state matrix
 static void MixColumns(unsigned astate[16])
 {
 	int i;

 	for (i = 0; i < 16; i += 4) {
 		unsigned a, b, c, d;
 		unsigned x, y, z, t;

 		a = astate[i + 0];
 		b = astate[i + 1];
 		c = astate[i + 2];
 		d = astate[i + 3];
 		x = (a << 1) ^ b ^ (b << 1) ^ c ^ d;
 		y = a ^ (b << 1) ^ c ^ (c << 1) ^ d;
 		z = a ^ b ^ (c << 1) ^ d ^ (d << 1);
 		t = a ^ (a << 1) ^ b ^ c ^ (d << 1);
 		astate[i + 0] = x ^ ((-(int)(x >> 8)) & 0x11b);
 		astate[i + 1] = y ^ ((-(int)(y >> 8)) & 0x11b);
 		astate[i + 2] = z ^ ((-(int)(z >> 8)) & 0x11b);
 		astate[i + 3] = t ^ ((-(int)(t >> 8)) & 0x11b);
 	}
 }

 // The SubBytes Function Substitutes the values in the
 // state matrix with values in an S-box.
 static void InvSubBytes(unsigned astate[16])
 {
 	int i;

 	for (i = 0; i < 16; i++)
 		astate[i] = rsbox[astate[i]];
 }

 static void InvShiftRows(unsigned astate[16])
 {
 	unsigned v;

 	// Rotate first row 1 columns to right
 	v = ASTATE(3,1);
 	ASTATE(3,1) = ASTATE(2,1);
 	ASTATE(2,1) = ASTATE(1,1);
 	ASTATE(1,1) = ASTATE(0,1);
 	ASTATE(0,1) = v;

 	// Rotate second row 2 columns to right
 	v = ASTATE(0,2); ASTATE(0,2) = ASTATE(2,2); ASTATE(2,2) = v;
 	v = ASTATE(1,2); ASTATE(1,2) = ASTATE(3,2); ASTATE(3,2) = v;

 	// Rotate third row 3 columns to right
 	v = ASTATE(0,3);
 	ASTATE(0,3) = ASTATE(1,3);
 	ASTATE(1,3) = ASTATE(2,3);
 	ASTATE(2,3) = ASTATE(3,3);
 	ASTATE(3,3) = v;
 }

 static ALWAYS_INLINE unsigned Multiply(unsigned x)
 {
 	unsigned y;

 	y = x >> 8;
 	return (x ^ y ^ (y << 1) ^ (y << 3) ^ (y << 4)) & 255;
 }

 // MixColumns function mixes the columns of the state matrix.
 // The method used to multiply may be difficult to understand for the inexperienced.
 // Please use the references to gain more information.
 static void InvMixColumns(unsigned astate[16])
 {
 	int i;

 	for (i = 0; i < 16; i += 4) {
 		unsigned a, b, c, d;
 		unsigned x, y, z, t;

 		a = astate[i + 0];
 		b = astate[i + 1];
 		c = astate[i + 2];
 		d = astate[i + 3];
 		x = (a << 1) ^ (a << 2) ^ (a << 3) ^ b ^ (b << 1) ^ (b << 3)
 		/***/ ^ c ^ (c << 2) ^ (c << 3) ^ d ^ (d << 3);
 		y = a ^ (a << 3) ^ (b << 1) ^ (b << 2) ^ (b << 3)
 		/***/ ^ c ^ (c << 1) ^ (c << 3) ^ d ^ (d << 2) ^ (d << 3);
 		z = a ^ (a << 2) ^ (a << 3) ^ b ^ (b << 3)
 		/***/ ^ (c << 1) ^ (c << 2) ^ (c << 3) ^ d ^ (d << 1) ^ (d << 3);
 		t = a ^ (a << 1) ^ (a << 3) ^ b ^ (b << 2) ^ (b << 3)
 		/***/ ^ c ^ (c << 3) ^ (d << 1) ^ (d << 2) ^ (d << 3);
 		astate[i + 0] = Multiply(x);
 		astate[i + 1] = Multiply(y);
 		astate[i + 2] = Multiply(z);
 		astate[i + 3] = Multiply(t);
 	}
 }

 static void aes_encrypt_1(unsigned astate[16], unsigned rounds, const uint32_t *RoundKey)
 {
 	for (;;) {
 		AddRoundKey(astate, RoundKey);
 		RoundKey += 4;
 		SubBytes(astate);
 		ShiftRows(astate);
 		if (--rounds == 0)
 			break;
 		MixColumns(astate);
 	}
 	AddRoundKey(astate, RoundKey);
 }

 #if 0 // UNUSED
 static void aes_encrypt_one_block(unsigned rounds, const uint32_t *RoundKey, const void *data, void *dst)
 {
 	unsigned astate[16];
 	unsigned i;

 	const uint8_t *pt = data;
 	uint8_t *ct = dst;

 	for (i = 0; i < 16; i++)
 		astate[i] = pt[i];
 	aes_encrypt_1(astate, rounds, RoundKey);
 	for (i = 0; i < 16; i++)
 		ct[i] = astate[i];
 }
 #endif

 void aes_cbc_encrypt(const void *key, int klen, void *iv, const void *data, size_t len, void *dst)
 {
 	uint32_t RoundKey[60];
 	uint8_t iv2[16];
 	unsigned rounds;

 	const uint8_t *pt = data;
 	uint8_t *ct = dst;

 	memcpy(iv2, iv, 16);
 	rounds = KeyExpansion(RoundKey, key, klen);
 	while (len > 0) {
 		{
 			/* almost aes_encrypt_one_block(rounds, RoundKey, pt, ct);
 			 * but xor'ing of IV with plaintext[] is combined
 			 * with plaintext[] -> astate[]
 			 */
 			int i;
 			unsigned astate[16];
 			for (i = 0; i < 16; i++)
 				astate[i] = pt[i] ^ iv2[i];
 			aes_encrypt_1(astate, rounds, RoundKey);
 			for (i = 0; i < 16; i++)
 				iv2[i] = ct[i] = astate[i];
 		}
 		ct += 16;
 		pt += 16;
 		len -= 16;
 	}
 }

 static void aes_decrypt_1(unsigned astate[16], unsigned rounds, const uint32_t *RoundKey)
 {
 	RoundKey += rounds * 4;
 	AddRoundKey(astate, RoundKey);
 	for (;;) {
 		InvShiftRows(astate);
 		InvSubBytes(astate);
 		RoundKey -= 4;
 		AddRoundKey(astate, RoundKey);
 		if (--rounds == 0)
 			break;
 		InvMixColumns(astate);
 	}
 }

 #if 0 //UNUSED
 static void aes_decrypt_one_block(unsigned rounds, const uint32_t *RoundKey, const void *data, void *dst)
 {
 	unsigned astate[16];
 	unsigned i;

 	const uint8_t *ct = data;
 	uint8_t *pt = dst;

 	for (i = 0; i < 16; i++)
 		astate[i] = ct[i];
 	aes_decrypt_1(astate, rounds, RoundKey);
 	for (i = 0; i < 16; i++)
 		pt[i] = astate[i];
 }
 #endif

 void aes_cbc_decrypt(const void *key, int klen, void *iv, const void *data, size_t len, void *dst)
 {
 	uint32_t RoundKey[60];
 	uint8_t iv2[16];
 	uint8_t iv3[16];
 	unsigned rounds;
 	uint8_t *ivbuf;
 	uint8_t *ivnext;

 	const uint8_t *ct = data;
 	uint8_t *pt = dst;

 	rounds = KeyExpansion(RoundKey, key, klen);
 	ivbuf = memcpy(iv2, iv, 16);
 	while (len) {
 		ivnext = (ivbuf==iv2) ? iv3 : iv2;
 		{
 			/* almost aes_decrypt_one_block(rounds, RoundKey, ct, pt)
 			 * but xor'ing of ivbuf is combined with astate[] -> plaintext[]
 			 */
 			int i;
 			unsigned astate[16];
 			for (i = 0; i < 16; i++)
 				ivnext[i] = astate[i] = ct[i];
 			aes_decrypt_1(astate, rounds, RoundKey);
 			for (i = 0; i < 16; i++)
 				pt[i] = astate[i] ^ ivbuf[i];
 		}
 		ivbuf = ivnext;
 		ct += 16;
 		pt += 16;
 		len -= 16;
 	}
 }
	/*
	* Copyright (C) 2017 Denys Vlasenko
	*
	* Licensed under GPLv2, see file LICENSE in this source tree.
	*/

	/* This AES implementation is derived from tiny-AES128-C code,
	* which was put by its author into public domain:
	*
	* tiny-AES128-C/unlicense.txt, Dec 8, 2014
	* """
	* This is free and unencumbered software released into the public domain.
	*
	* Anyone is free to copy, modify, publish, use, compile, sell, or
	* distribute this software, either in source code form or as a compiled
	* binary, for any purpose, commercial or non-commercial, and by any
	* means.
	*
	* In jurisdictions that recognize copyright laws, the author or authors
	* of this software dedicate any and all copyright interest in the
	* software to the public domain. We make this dedication for the benefit
	* of the public at large and to the detriment of our heirs and
	* successors. We intend this dedication to be an overt act of
	* relinquishment in perpetuity of all present and future rights to this
	* software under copyright law.
	*
	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
	* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
	* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
	* IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR
	* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
	* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
	* OTHER DEALINGS IN THE SOFTWARE.
	* """
	*/
	/* Note that only original tiny-AES128-C code is public domain.
	* The derived code in this file has been expanded to also implement aes192
	* and aes256 and use more efficient word-sized operations in many places,
	* and put under GPLv2 license.
	*/
	#include "tls.h"

	// The lookup-tables are marked const so they can be placed in read-only storage instead of RAM
	// The numbers below can be computed dynamically trading ROM for RAM -
	// This can be useful in (embedded) bootloader applications, where ROM is often limited.
	static const uint8_t sbox[] = {
	0x63, 0x7c, 0x77, 0x7b, 0xf2, 0x6b, 0x6f, 0xc5,
	0x30, 0x01, 0x67, 0x2b, 0xfe, 0xd7, 0xab, 0x76,
	0xca, 0x82, 0xc9, 0x7d, 0xfa, 0x59, 0x47, 0xf0,
	0xad, 0xd4, 0xa2, 0xaf, 0x9c, 0xa4, 0x72, 0xc0,
	0xb7, 0xfd, 0x93, 0x26, 0x36, 0x3f, 0xf7, 0xcc,
	0x34, 0xa5, 0xe5, 0xf1, 0x71, 0xd8, 0x31, 0x15,
	0x04, 0xc7, 0x23, 0xc3, 0x18, 0x96, 0x05, 0x9a,
	0x07, 0x12, 0x80, 0xe2, 0xeb, 0x27, 0xb2, 0x75,
	0x09, 0x83, 0x2c, 0x1a, 0x1b, 0x6e, 0x5a, 0xa0,
	0x52, 0x3b, 0xd6, 0xb3, 0x29, 0xe3, 0x2f, 0x84,
	0x53, 0xd1, 0x00, 0xed, 0x20, 0xfc, 0xb1, 0x5b,
	0x6a, 0xcb, 0xbe, 0x39, 0x4a, 0x4c, 0x58, 0xcf,
	0xd0, 0xef, 0xaa, 0xfb, 0x43, 0x4d, 0x33, 0x85,
	0x45, 0xf9, 0x02, 0x7f, 0x50, 0x3c, 0x9f, 0xa8,
	0x51, 0xa3, 0x40, 0x8f, 0x92, 0x9d, 0x38, 0xf5,
	0xbc, 0xb6, 0xda, 0x21, 0x10, 0xff, 0xf3, 0xd2,
	0xcd, 0x0c, 0x13, 0xec, 0x5f, 0x97, 0x44, 0x17,
	0xc4, 0xa7, 0x7e, 0x3d, 0x64, 0x5d, 0x19, 0x73,
	0x60, 0x81, 0x4f, 0xdc, 0x22, 0x2a, 0x90, 0x88,
	0x46, 0xee, 0xb8, 0x14, 0xde, 0x5e, 0x0b, 0xdb,
	0xe0, 0x32, 0x3a, 0x0a, 0x49, 0x06, 0x24, 0x5c,
	0xc2, 0xd3, 0xac, 0x62, 0x91, 0x95, 0xe4, 0x79,
	0xe7, 0xc8, 0x37, 0x6d, 0x8d, 0xd5, 0x4e, 0xa9,
	0x6c, 0x56, 0xf4, 0xea, 0x65, 0x7a, 0xae, 0x08,
	0xba, 0x78, 0x25, 0x2e, 0x1c, 0xa6, 0xb4, 0xc6,
	0xe8, 0xdd, 0x74, 0x1f, 0x4b, 0xbd, 0x8b, 0x8a,
	0x70, 0x3e, 0xb5, 0x66, 0x48, 0x03, 0xf6, 0x0e,
	0x61, 0x35, 0x57, 0xb9, 0x86, 0xc1, 0x1d, 0x9e,
	0xe1, 0xf8, 0x98, 0x11, 0x69, 0xd9, 0x8e, 0x94,
	0x9b, 0x1e, 0x87, 0xe9, 0xce, 0x55, 0x28, 0xdf,
	0x8c, 0xa1, 0x89, 0x0d, 0xbf, 0xe6, 0x42, 0x68,
	0x41, 0x99, 0x2d, 0x0f, 0xb0, 0x54, 0xbb, 0x16,
	};

	static const uint8_t rsbox[] = {
	0x52, 0x09, 0x6a, 0xd5, 0x30, 0x36, 0xa5, 0x38,
	0xbf, 0x40, 0xa3, 0x9e, 0x81, 0xf3, 0xd7, 0xfb,
	0x7c, 0xe3, 0x39, 0x82, 0x9b, 0x2f, 0xff, 0x87,
	0x34, 0x8e, 0x43, 0x44, 0xc4, 0xde, 0xe9, 0xcb,
	0x54, 0x7b, 0x94, 0x32, 0xa6, 0xc2, 0x23, 0x3d,
	0xee, 0x4c, 0x95, 0x0b, 0x42, 0xfa, 0xc3, 0x4e,
	0x08, 0x2e, 0xa1, 0x66, 0x28, 0xd9, 0x24, 0xb2,
	0x76, 0x5b, 0xa2, 0x49, 0x6d, 0x8b, 0xd1, 0x25,
	0x72, 0xf8, 0xf6, 0x64, 0x86, 0x68, 0x98, 0x16,
	0xd4, 0xa4, 0x5c, 0xcc, 0x5d, 0x65, 0xb6, 0x92,
	0x6c, 0x70, 0x48, 0x50, 0xfd, 0xed, 0xb9, 0xda,
	0x5e, 0x15, 0x46, 0x57, 0xa7, 0x8d, 0x9d, 0x84,
	0x90, 0xd8, 0xab, 0x00, 0x8c, 0xbc, 0xd3, 0x0a,
	0xf7, 0xe4, 0x58, 0x05, 0xb8, 0xb3, 0x45, 0x06,
	0xd0, 0x2c, 0x1e, 0x8f, 0xca, 0x3f, 0x0f, 0x02,
	0xc1, 0xaf, 0xbd, 0x03, 0x01, 0x13, 0x8a, 0x6b,
	0x3a, 0x91, 0x11, 0x41, 0x4f, 0x67, 0xdc, 0xea,
	0x97, 0xf2, 0xcf, 0xce, 0xf0, 0xb4, 0xe6, 0x73,
	0x96, 0xac, 0x74, 0x22, 0xe7, 0xad, 0x35, 0x85,
	0xe2, 0xf9, 0x37, 0xe8, 0x1c, 0x75, 0xdf, 0x6e,
	0x47, 0xf1, 0x1a, 0x71, 0x1d, 0x29, 0xc5, 0x89,
	0x6f, 0xb7, 0x62, 0x0e, 0xaa, 0x18, 0xbe, 0x1b,
	0xfc, 0x56, 0x3e, 0x4b, 0xc6, 0xd2, 0x79, 0x20,
	0x9a, 0xdb, 0xc0, 0xfe, 0x78, 0xcd, 0x5a, 0xf4,
	0x1f, 0xdd, 0xa8, 0x33, 0x88, 0x07, 0xc7, 0x31,
	0xb1, 0x12, 0x10, 0x59, 0x27, 0x80, 0xec, 0x5f,
	0x60, 0x51, 0x7f, 0xa9, 0x19, 0xb5, 0x4a, 0x0d,
	0x2d, 0xe5, 0x7a, 0x9f, 0x93, 0xc9, 0x9c, 0xef,
	0xa0, 0xe0, 0x3b, 0x4d, 0xae, 0x2a, 0xf5, 0xb0,
	0xc8, 0xeb, 0xbb, 0x3c, 0x83, 0x53, 0x99, 0x61,
	0x17, 0x2b, 0x04, 0x7e, 0xba, 0x77, 0xd6, 0x26,
	0xe1, 0x69, 0x14, 0x63, 0x55, 0x21, 0x0c, 0x7d,
	};

	// SubWord() is a function that takes a four-byte input word and
	// applies the S-box to each of the four bytes to produce an output word.
	static uint32_t Subword(uint32_t x)
	{
	return (sbox[(x >> 24) ] << 24)
	\| (sbox[(x >> 16) & 255] << 16)
	\| (sbox[(x >> 8 ) & 255] << 8 )
	\| (sbox[(x ) & 255] );
	}

	// This function produces Nb(Nr+1) round keys.
	// The round keys are used in each round to decrypt the states.
	static int KeyExpansion(uint32_t RoundKey, const void key, unsigned key_len)
	{
	// The round constant word array, Rcon[i], contains the values given by
	// x to th e power (i-1) being powers of x (x is denoted as {02}) in the field GF(2^8).
	// Note that i starts at 2, not 0.
	static const uint8_t Rcon[] = {
	0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36
	//..... 0x6c, 0xd8, 0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc, 0x63, 0xc6,...
	// but aes256 only uses values up to 0x36
	};
	int rounds, words_key, words_RoundKey;
	int i, j, k;

	// key_len 16: aes128, rounds 10, words_key 4, words_RoundKey 44
	// key_len 24: aes192, rounds 12, words_key 6, words_RoundKey 52
	// key_len 32: aes256, rounds 14, words_key 8, words_RoundKey 60
	words_key = key_len / 4;
	rounds = 6 + (key_len / 4);
	words_RoundKey = 28 + key_len;

	// The first round key is the key itself.
	for (i = 0; i < words_key; i++)
	RoundKey[i] = get_unaligned_be32((uint32_t*)key + i);
	// i == words_key now

	// All other round keys are found from the previous round keys.
	j = k = 0;
	for (; i < words_RoundKey; i++) {
	uint32_t tempa;

	tempa = RoundKey[i - 1];
	if (j == 0) {
	// RotWord(): rotates the 4 bytes in a word to the left once.
	tempa = (tempa << 8) \| (tempa >> 24);
	tempa = Subword(tempa);
	tempa ^= (uint32_t)Rcon[k] << 24;
	} else if (words_key > 6 && j == 4) {
	tempa = Subword(tempa);
	}
	RoundKey[i] = RoundKey[i - words_key] ^ tempa;
	j++;
	if (j == words_key) {
	j = 0;
	k++;
	}
	}
	return rounds;
	}

	// This function adds the round key to state.
	// The round key is added to the state by an XOR function.
	static void AddRoundKey(unsigned astate[16], const uint32_t *RoundKeys)
	{
	int i;

	for (i = 0; i < 16; i += 4) {
	uint32_t n = *RoundKeys++;
	astate[i + 0] ^= (n >> 24);
	astate[i + 1] ^= (n >> 16) & 255;
	astate[i + 2] ^= (n >> 8) & 255;
	astate[i + 3] ^= n & 255;
	}
	}

	// The SubBytes Function Substitutes the values in the
	// state matrix with values in an S-box.
	static void SubBytes(unsigned astate[16])
	{
	int i;

	for (i = 0; i < 16; i++)
	astate[i] = sbox[astate[i]];
	}

	// Our code actually stores "columns" (in aes encryption terminology)
	// of state in rows: first 4 elements are "row 0, col 0", "row 1, col 0".
	// "row 2, col 0", "row 3, col 0". The fifth element is "row 0, col 1",
	// and so on.
	#define ASTATE(col,row) astate[(col)*4 + (row)]

	// The ShiftRows() function shifts the rows in the state to the left.
	// Each row is shifted with different offset.
	// Offset = Row number. So the first row is not shifted.
	static void ShiftRows(unsigned astate[16])
	{
	unsigned v;

	// Rotate first row 1 columns to left
	v = ASTATE(0,1);
	ASTATE(0,1) = ASTATE(1,1);
	ASTATE(1,1) = ASTATE(2,1);
	ASTATE(2,1) = ASTATE(3,1);
	ASTATE(3,1) = v;

	// Rotate second row 2 columns to left
	v = ASTATE(0,2); ASTATE(0,2) = ASTATE(2,2); ASTATE(2,2) = v;
	v = ASTATE(1,2); ASTATE(1,2) = ASTATE(3,2); ASTATE(3,2) = v;

	// Rotate third row 3 columns to left
	v = ASTATE(3,3);
	ASTATE(3,3) = ASTATE(2,3);
	ASTATE(2,3) = ASTATE(1,3);
	ASTATE(1,3) = ASTATE(0,3);
	ASTATE(0,3) = v;
	}

	// MixColumns function mixes the columns of the state matrix
	static void MixColumns(unsigned astate[16])
	{
	int i;

	for (i = 0; i < 16; i += 4) {
	unsigned a, b, c, d;
	unsigned x, y, z, t;

	a = astate[i + 0];
	b = astate[i + 1];
	c = astate[i + 2];
	d = astate[i + 3];
	x = (a << 1) ^ b ^ (b << 1) ^ c ^ d;
	y = a ^ (b << 1) ^ c ^ (c << 1) ^ d;
	z = a ^ b ^ (c << 1) ^ d ^ (d << 1);
	t = a ^ (a << 1) ^ b ^ c ^ (d << 1);
	astate[i + 0] = x ^ ((-(int)(x >> 8)) & 0x11b);
	astate[i + 1] = y ^ ((-(int)(y >> 8)) & 0x11b);
	astate[i + 2] = z ^ ((-(int)(z >> 8)) & 0x11b);
	astate[i + 3] = t ^ ((-(int)(t >> 8)) & 0x11b);
	}
	}

	// The SubBytes Function Substitutes the values in the
	// state matrix with values in an S-box.
	static void InvSubBytes(unsigned astate[16])
	{
	int i;

	for (i = 0; i < 16; i++)
	astate[i] = rsbox[astate[i]];
	}

	static void InvShiftRows(unsigned astate[16])
	{
	unsigned v;

	// Rotate first row 1 columns to right
	v = ASTATE(3,1);
	ASTATE(3,1) = ASTATE(2,1);
	ASTATE(2,1) = ASTATE(1,1);
	ASTATE(1,1) = ASTATE(0,1);
	ASTATE(0,1) = v;

	// Rotate second row 2 columns to right
	v = ASTATE(0,2); ASTATE(0,2) = ASTATE(2,2); ASTATE(2,2) = v;
	v = ASTATE(1,2); ASTATE(1,2) = ASTATE(3,2); ASTATE(3,2) = v;

	// Rotate third row 3 columns to right
	v = ASTATE(0,3);
	ASTATE(0,3) = ASTATE(1,3);
	ASTATE(1,3) = ASTATE(2,3);
	ASTATE(2,3) = ASTATE(3,3);
	ASTATE(3,3) = v;
	}

	static ALWAYS_INLINE unsigned Multiply(unsigned x)
	{
	unsigned y;

	y = x >> 8;
	return (x ^ y ^ (y << 1) ^ (y << 3) ^ (y << 4)) & 255;
	}

	// MixColumns function mixes the columns of the state matrix.
	// The method used to multiply may be difficult to understand for the inexperienced.
	// Please use the references to gain more information.
	static void InvMixColumns(unsigned astate[16])
	{
	int i;

	for (i = 0; i < 16; i += 4) {
	unsigned a, b, c, d;
	unsigned x, y, z, t;

	a = astate[i + 0];
	b = astate[i + 1];
	c = astate[i + 2];
	d = astate[i + 3];
	x = (a << 1) ^ (a << 2) ^ (a << 3) ^ b ^ (b << 1) ^ (b << 3)
	/***/ ^ c ^ (c << 2) ^ (c << 3) ^ d ^ (d << 3);
	y = a ^ (a << 3) ^ (b << 1) ^ (b << 2) ^ (b << 3)
	/***/ ^ c ^ (c << 1) ^ (c << 3) ^ d ^ (d << 2) ^ (d << 3);
	z = a ^ (a << 2) ^ (a << 3) ^ b ^ (b << 3)
	/***/ ^ (c << 1) ^ (c << 2) ^ (c << 3) ^ d ^ (d << 1) ^ (d << 3);
	t = a ^ (a << 1) ^ (a << 3) ^ b ^ (b << 2) ^ (b << 3)
	/***/ ^ c ^ (c << 3) ^ (d << 1) ^ (d << 2) ^ (d << 3);
	astate[i + 0] = Multiply(x);
	astate[i + 1] = Multiply(y);
	astate[i + 2] = Multiply(z);
	astate[i + 3] = Multiply(t);
	}
	}

	static void aes_encrypt_1(unsigned astate[16], unsigned rounds, const uint32_t *RoundKey)
	{
	for (;;) {
	AddRoundKey(astate, RoundKey);
	RoundKey += 4;
	SubBytes(astate);
	ShiftRows(astate);
	if (--rounds == 0)
	break;
	MixColumns(astate);
	}
	AddRoundKey(astate, RoundKey);
	}

	#if 0 // UNUSED
	static void aes_encrypt_one_block(unsigned rounds, const uint32_t RoundKey, const void data, void *dst)
	{
	unsigned astate[16];
	unsigned i;

	const uint8_t *pt = data;
	uint8_t *ct = dst;

	for (i = 0; i < 16; i++)
	astate[i] = pt[i];
	aes_encrypt_1(astate, rounds, RoundKey);
	for (i = 0; i < 16; i++)
	ct[i] = astate[i];
	}
	#endif

	void aes_cbc_encrypt(const void key, int klen, void iv, const void data, size_t len, void dst)
	{
	uint32_t RoundKey[60];
	uint8_t iv2[16];
	unsigned rounds;

	const uint8_t *pt = data;
	uint8_t *ct = dst;

	memcpy(iv2, iv, 16);
	rounds = KeyExpansion(RoundKey, key, klen);
	while (len > 0) {
	{
	/* almost aes_encrypt_one_block(rounds, RoundKey, pt, ct);
	* but xor'ing of IV with plaintext[] is combined
	* with plaintext[] -> astate[]
	*/
	int i;
	unsigned astate[16];
	for (i = 0; i < 16; i++)
	astate[i] = pt[i] ^ iv2[i];
	aes_encrypt_1(astate, rounds, RoundKey);
	for (i = 0; i < 16; i++)
	iv2[i] = ct[i] = astate[i];
	}
	ct += 16;
	pt += 16;
	len -= 16;
	}
	}

	static void aes_decrypt_1(unsigned astate[16], unsigned rounds, const uint32_t *RoundKey)
	{
	RoundKey += rounds * 4;
	AddRoundKey(astate, RoundKey);
	for (;;) {
	InvShiftRows(astate);
	InvSubBytes(astate);
	RoundKey -= 4;
	AddRoundKey(astate, RoundKey);
	if (--rounds == 0)
	break;
	InvMixColumns(astate);
	}
	}

	#if 0 //UNUSED
	static void aes_decrypt_one_block(unsigned rounds, const uint32_t RoundKey, const void data, void *dst)
	{
	unsigned astate[16];
	unsigned i;

	const uint8_t *ct = data;
	uint8_t *pt = dst;

	for (i = 0; i < 16; i++)
	astate[i] = ct[i];
	aes_decrypt_1(astate, rounds, RoundKey);
	for (i = 0; i < 16; i++)
	pt[i] = astate[i];
	}
	#endif

	void aes_cbc_decrypt(const void key, int klen, void iv, const void data, size_t len, void dst)
	{
	uint32_t RoundKey[60];
	uint8_t iv2[16];
	uint8_t iv3[16];
	unsigned rounds;
	uint8_t *ivbuf;
	uint8_t *ivnext;

	const uint8_t *ct = data;
	uint8_t *pt = dst;

	rounds = KeyExpansion(RoundKey, key, klen);
	ivbuf = memcpy(iv2, iv, 16);
	while (len) {
	ivnext = (ivbuf==iv2) ? iv3 : iv2;
	{
	/* almost aes_decrypt_one_block(rounds, RoundKey, ct, pt)
	* but xor'ing of ivbuf is combined with astate[] -> plaintext[]
	*/
	int i;
	unsigned astate[16];
	for (i = 0; i < 16; i++)
	ivnext[i] = astate[i] = ct[i];
	aes_decrypt_1(astate, rounds, RoundKey);
	for (i = 0; i < 16; i++)
	pt[i] = astate[i] ^ ivbuf[i];
	}
	ivbuf = ivnext;
	ct += 16;
	pt += 16;
	len -= 16;
	}
	}