Helmut Tschemernjak / RadioShuttle-STM32L4

RadioShuttle Lib for the STM32 L4 Heltec Board

Dependents:   Turtle_RadioShuttle

util/aes.c@13:591254bed18b, 2019-04-14 (annotated)

Committer:
Helmut Tschemernjak
Date:
Sun Apr 14 18:35:26 2019 +0200
Revision:
13:591254bed18b
Parent:
0:0c31756924a2 
Updated RadioStatus to be in common with mbed and Arduino

Who changed what in which revision?

UserRevisionLine numberNew contents of line
Helmut64 0:0c31756924a2 1 /*
Helmut64 0:0c31756924a2 2 Downloaded from here: https://github.com/kokke/tiny-AES128-C
Helmut64 0:0c31756924a2 3 This is an implementation of the AES128 algorithm, specifically ECB and CBC mode.
Helmut64 0:0c31756924a2 4
Helmut64 0:0c31756924a2 5 The implementation is verified against the test vectors in:
Helmut64 0:0c31756924a2 6 National Institute of Standards and Technology Special Publication 800-38A 2001 ED
Helmut64 0:0c31756924a2 7
Helmut64 0:0c31756924a2 8 ECB-AES128
Helmut64 0:0c31756924a2 9 ----------
Helmut64 0:0c31756924a2 10
Helmut64 0:0c31756924a2 11 plain-text:
Helmut64 0:0c31756924a2 12 6bc1bee22e409f96e93d7e117393172a
Helmut64 0:0c31756924a2 13 ae2d8a571e03ac9c9eb76fac45af8e51
Helmut64 0:0c31756924a2 14 30c81c46a35ce411e5fbc1191a0a52ef
Helmut64 0:0c31756924a2 15 f69f2445df4f9b17ad2b417be66c3710
Helmut64 0:0c31756924a2 16
Helmut64 0:0c31756924a2 17 key:
Helmut64 0:0c31756924a2 18 2b7e151628aed2a6abf7158809cf4f3c
Helmut64 0:0c31756924a2 19
Helmut64 0:0c31756924a2 20 resulting cipher
Helmut64 0:0c31756924a2 21 3ad77bb40d7a3660a89ecaf32466ef97
Helmut64 0:0c31756924a2 22 f5d3d58503b9699de785895a96fdbaaf
Helmut64 0:0c31756924a2 23 43b1cd7f598ece23881b00e3ed030688
Helmut64 0:0c31756924a2 24 7b0c785e27e8ad3f8223207104725dd4
Helmut64 0:0c31756924a2 25
Helmut64 0:0c31756924a2 26
Helmut64 0:0c31756924a2 27 NOTE: String length must be evenly divisible by 16byte (str_len % 16 == 0)
Helmut64 0:0c31756924a2 28 You should pad the end of the string with zeros if this is not the case.
Helmut64 0:0c31756924a2 29
Helmut64 0:0c31756924a2 30 */
Helmut64 0:0c31756924a2 31
Helmut64 0:0c31756924a2 32
Helmut64 0:0c31756924a2 33 /*****************************************************************************/
Helmut64 0:0c31756924a2 34 /* Includes: */
Helmut64 0:0c31756924a2 35 /*****************************************************************************/
Helmut64 0:0c31756924a2 36 #include <stdint.h>
Helmut64 0:0c31756924a2 37 #include <string.h> // CBC mode, for memset
Helmut64 0:0c31756924a2 38 #include "aes.h"
Helmut64 0:0c31756924a2 39
Helmut64 0:0c31756924a2 40 /*****************************************************************************/
Helmut64 0:0c31756924a2 41 /* Defines: */
Helmut64 0:0c31756924a2 42 /*****************************************************************************/
Helmut64 0:0c31756924a2 43 // The number of columns comprising a state in AES. This is a constant in AES. Value=4
Helmut64 0:0c31756924a2 44 #define Nb 4
Helmut64 0:0c31756924a2 45 // The number of 32 bit words in a key.
Helmut64 0:0c31756924a2 46 #define Nk 4
Helmut64 0:0c31756924a2 47
Helmut64 0:0c31756924a2 48 // jcallan@github points out that declaring Multiply as a function
Helmut64 0:0c31756924a2 49 // reduces code size considerably with the Keil ARM compiler.
Helmut64 0:0c31756924a2 50 // See this link for more information: https://github.com/kokke/tiny-AES128-C/pull/3
Helmut64 0:0c31756924a2 51 #ifndef MULTIPLY_AS_A_FUNCTION
Helmut64 0:0c31756924a2 52 #define MULTIPLY_AS_A_FUNCTION 1
Helmut64 0:0c31756924a2 53 #endif
Helmut64 0:0c31756924a2 54
Helmut64 0:0c31756924a2 55 /*
Helmut64 0:0c31756924a2 56 * simple re-defines do use the existing code with a context
Helmut64 0:0c31756924a2 57 */
Helmut64 0:0c31756924a2 58 #define state ctx->state
Helmut64 0:0c31756924a2 59 #define RoundKey ctx->RoundKey
Helmut64 0:0c31756924a2 60 #define Iv ctx->InitialVector
Helmut64 0:0c31756924a2 61 #define KEYLEN AES128_KEYLEN
Helmut64 0:0c31756924a2 62
Helmut64 0:0c31756924a2 63 // The lookup-tables are marked const so they can be placed in read-only storage instead of RAM
Helmut64 0:0c31756924a2 64 // The numbers below can be computed dynamically trading ROM for RAM -
Helmut64 0:0c31756924a2 65 // This can be useful in (embedded) bootloader applications, where ROM is often limited.
Helmut64 0:0c31756924a2 66 static const uint8_t sbox[256] = {
Helmut64 0:0c31756924a2 67 //0 1 2 3 4 5 6 7 8 9 A B C D E F
Helmut64 0:0c31756924a2 68 0x63, 0x7c, 0x77, 0x7b, 0xf2, 0x6b, 0x6f, 0xc5, 0x30, 0x01, 0x67, 0x2b, 0xfe, 0xd7, 0xab, 0x76,
Helmut64 0:0c31756924a2 69 0xca, 0x82, 0xc9, 0x7d, 0xfa, 0x59, 0x47, 0xf0, 0xad, 0xd4, 0xa2, 0xaf, 0x9c, 0xa4, 0x72, 0xc0,
Helmut64 0:0c31756924a2 70 0xb7, 0xfd, 0x93, 0x26, 0x36, 0x3f, 0xf7, 0xcc, 0x34, 0xa5, 0xe5, 0xf1, 0x71, 0xd8, 0x31, 0x15,
Helmut64 0:0c31756924a2 71 0x04, 0xc7, 0x23, 0xc3, 0x18, 0x96, 0x05, 0x9a, 0x07, 0x12, 0x80, 0xe2, 0xeb, 0x27, 0xb2, 0x75,
Helmut64 0:0c31756924a2 72 0x09, 0x83, 0x2c, 0x1a, 0x1b, 0x6e, 0x5a, 0xa0, 0x52, 0x3b, 0xd6, 0xb3, 0x29, 0xe3, 0x2f, 0x84,
Helmut64 0:0c31756924a2 73 0x53, 0xd1, 0x00, 0xed, 0x20, 0xfc, 0xb1, 0x5b, 0x6a, 0xcb, 0xbe, 0x39, 0x4a, 0x4c, 0x58, 0xcf,
Helmut64 0:0c31756924a2 74 0xd0, 0xef, 0xaa, 0xfb, 0x43, 0x4d, 0x33, 0x85, 0x45, 0xf9, 0x02, 0x7f, 0x50, 0x3c, 0x9f, 0xa8,
Helmut64 0:0c31756924a2 75 0x51, 0xa3, 0x40, 0x8f, 0x92, 0x9d, 0x38, 0xf5, 0xbc, 0xb6, 0xda, 0x21, 0x10, 0xff, 0xf3, 0xd2,
Helmut64 0:0c31756924a2 76 0xcd, 0x0c, 0x13, 0xec, 0x5f, 0x97, 0x44, 0x17, 0xc4, 0xa7, 0x7e, 0x3d, 0x64, 0x5d, 0x19, 0x73,
Helmut64 0:0c31756924a2 77 0x60, 0x81, 0x4f, 0xdc, 0x22, 0x2a, 0x90, 0x88, 0x46, 0xee, 0xb8, 0x14, 0xde, 0x5e, 0x0b, 0xdb,
Helmut64 0:0c31756924a2 78 0xe0, 0x32, 0x3a, 0x0a, 0x49, 0x06, 0x24, 0x5c, 0xc2, 0xd3, 0xac, 0x62, 0x91, 0x95, 0xe4, 0x79,
Helmut64 0:0c31756924a2 79 0xe7, 0xc8, 0x37, 0x6d, 0x8d, 0xd5, 0x4e, 0xa9, 0x6c, 0x56, 0xf4, 0xea, 0x65, 0x7a, 0xae, 0x08,
Helmut64 0:0c31756924a2 80 0xba, 0x78, 0x25, 0x2e, 0x1c, 0xa6, 0xb4, 0xc6, 0xe8, 0xdd, 0x74, 0x1f, 0x4b, 0xbd, 0x8b, 0x8a,
Helmut64 0:0c31756924a2 81 0x70, 0x3e, 0xb5, 0x66, 0x48, 0x03, 0xf6, 0x0e, 0x61, 0x35, 0x57, 0xb9, 0x86, 0xc1, 0x1d, 0x9e,
Helmut64 0:0c31756924a2 82 0xe1, 0xf8, 0x98, 0x11, 0x69, 0xd9, 0x8e, 0x94, 0x9b, 0x1e, 0x87, 0xe9, 0xce, 0x55, 0x28, 0xdf,
Helmut64 0:0c31756924a2 83 0x8c, 0xa1, 0x89, 0x0d, 0xbf, 0xe6, 0x42, 0x68, 0x41, 0x99, 0x2d, 0x0f, 0xb0, 0x54, 0xbb, 0x16 };
Helmut64 0:0c31756924a2 84
Helmut64 0:0c31756924a2 85 static const uint8_t rsbox[256] =
Helmut64 0:0c31756924a2 86 { 0x52, 0x09, 0x6a, 0xd5, 0x30, 0x36, 0xa5, 0x38, 0xbf, 0x40, 0xa3, 0x9e, 0x81, 0xf3, 0xd7, 0xfb,
Helmut64 0:0c31756924a2 87 0x7c, 0xe3, 0x39, 0x82, 0x9b, 0x2f, 0xff, 0x87, 0x34, 0x8e, 0x43, 0x44, 0xc4, 0xde, 0xe9, 0xcb,
Helmut64 0:0c31756924a2 88 0x54, 0x7b, 0x94, 0x32, 0xa6, 0xc2, 0x23, 0x3d, 0xee, 0x4c, 0x95, 0x0b, 0x42, 0xfa, 0xc3, 0x4e,
Helmut64 0:0c31756924a2 89 0x08, 0x2e, 0xa1, 0x66, 0x28, 0xd9, 0x24, 0xb2, 0x76, 0x5b, 0xa2, 0x49, 0x6d, 0x8b, 0xd1, 0x25,
Helmut64 0:0c31756924a2 90 0x72, 0xf8, 0xf6, 0x64, 0x86, 0x68, 0x98, 0x16, 0xd4, 0xa4, 0x5c, 0xcc, 0x5d, 0x65, 0xb6, 0x92,
Helmut64 0:0c31756924a2 91 0x6c, 0x70, 0x48, 0x50, 0xfd, 0xed, 0xb9, 0xda, 0x5e, 0x15, 0x46, 0x57, 0xa7, 0x8d, 0x9d, 0x84,
Helmut64 0:0c31756924a2 92 0x90, 0xd8, 0xab, 0x00, 0x8c, 0xbc, 0xd3, 0x0a, 0xf7, 0xe4, 0x58, 0x05, 0xb8, 0xb3, 0x45, 0x06,
Helmut64 0:0c31756924a2 93 0xd0, 0x2c, 0x1e, 0x8f, 0xca, 0x3f, 0x0f, 0x02, 0xc1, 0xaf, 0xbd, 0x03, 0x01, 0x13, 0x8a, 0x6b,
Helmut64 0:0c31756924a2 94 0x3a, 0x91, 0x11, 0x41, 0x4f, 0x67, 0xdc, 0xea, 0x97, 0xf2, 0xcf, 0xce, 0xf0, 0xb4, 0xe6, 0x73,
Helmut64 0:0c31756924a2 95 0x96, 0xac, 0x74, 0x22, 0xe7, 0xad, 0x35, 0x85, 0xe2, 0xf9, 0x37, 0xe8, 0x1c, 0x75, 0xdf, 0x6e,
Helmut64 0:0c31756924a2 96 0x47, 0xf1, 0x1a, 0x71, 0x1d, 0x29, 0xc5, 0x89, 0x6f, 0xb7, 0x62, 0x0e, 0xaa, 0x18, 0xbe, 0x1b,
Helmut64 0:0c31756924a2 97 0xfc, 0x56, 0x3e, 0x4b, 0xc6, 0xd2, 0x79, 0x20, 0x9a, 0xdb, 0xc0, 0xfe, 0x78, 0xcd, 0x5a, 0xf4,
Helmut64 0:0c31756924a2 98 0x1f, 0xdd, 0xa8, 0x33, 0x88, 0x07, 0xc7, 0x31, 0xb1, 0x12, 0x10, 0x59, 0x27, 0x80, 0xec, 0x5f,
Helmut64 0:0c31756924a2 99 0x60, 0x51, 0x7f, 0xa9, 0x19, 0xb5, 0x4a, 0x0d, 0x2d, 0xe5, 0x7a, 0x9f, 0x93, 0xc9, 0x9c, 0xef,
Helmut64 0:0c31756924a2 100 0xa0, 0xe0, 0x3b, 0x4d, 0xae, 0x2a, 0xf5, 0xb0, 0xc8, 0xeb, 0xbb, 0x3c, 0x83, 0x53, 0x99, 0x61,
Helmut64 0:0c31756924a2 101 0x17, 0x2b, 0x04, 0x7e, 0xba, 0x77, 0xd6, 0x26, 0xe1, 0x69, 0x14, 0x63, 0x55, 0x21, 0x0c, 0x7d };
Helmut64 0:0c31756924a2 102
Helmut64 0:0c31756924a2 103
Helmut64 0:0c31756924a2 104 // The round constant word array, Rcon[i], contains the values given by
Helmut64 0:0c31756924a2 105 // x to th e power (i-1) being powers of x (x is denoted as {02}) in the field GF(2^8)
Helmut64 0:0c31756924a2 106 // Note that i starts at 1, not 0).
Helmut64 0:0c31756924a2 107 static const uint8_t Rcon[10] = { 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36 };
Helmut64 0:0c31756924a2 108
Helmut64 0:0c31756924a2 109
Helmut64 0:0c31756924a2 110 /*****************************************************************************/
Helmut64 0:0c31756924a2 111 /* Private functions: */
Helmut64 0:0c31756924a2 112 /*****************************************************************************/
Helmut64 0:0c31756924a2 113 static uint8_t getSBoxValue(uint8_t num)
Helmut64 0:0c31756924a2 114 {
Helmut64 0:0c31756924a2 115 return sbox[num];
Helmut64 0:0c31756924a2 116 }
Helmut64 0:0c31756924a2 117
Helmut64 0:0c31756924a2 118 static uint8_t getSBoxInvert(uint8_t num)
Helmut64 0:0c31756924a2 119 {
Helmut64 0:0c31756924a2 120 return rsbox[num];
Helmut64 0:0c31756924a2 121 }
Helmut64 0:0c31756924a2 122
Helmut64 0:0c31756924a2 123 // This function produces Nb(Nr+1) round keys. The round keys are used in each round to decrypt the states.
Helmut64 0:0c31756924a2 124 static void KeyExpansion(AES_CTX *ctx, const uint8_t* Key)
Helmut64 0:0c31756924a2 125 {
Helmut64 0:0c31756924a2 126 uint32_t i, j, k;
Helmut64 0:0c31756924a2 127 uint8_t tempa[4]; // Used for the column/row operations
Helmut64 0:0c31756924a2 128
Helmut64 0:0c31756924a2 129 // The first round key is the key itself.
Helmut64 0:0c31756924a2 130 for(i = 0; i < Nk; ++i)
Helmut64 0:0c31756924a2 131 {
Helmut64 0:0c31756924a2 132 RoundKey[(i * 4) + 0] = Key[(i * 4) + 0];
Helmut64 0:0c31756924a2 133 RoundKey[(i * 4) + 1] = Key[(i * 4) + 1];
Helmut64 0:0c31756924a2 134 RoundKey[(i * 4) + 2] = Key[(i * 4) + 2];
Helmut64 0:0c31756924a2 135 RoundKey[(i * 4) + 3] = Key[(i * 4) + 3];
Helmut64 0:0c31756924a2 136 }
Helmut64 0:0c31756924a2 137
Helmut64 0:0c31756924a2 138 // All other round keys are found from the previous round keys.
Helmut64 0:0c31756924a2 139 for(; (i < (Nb * (Nr + 1))); ++i)
Helmut64 0:0c31756924a2 140 {
Helmut64 0:0c31756924a2 141 for(j = 0; j < 4; ++j)
Helmut64 0:0c31756924a2 142 {
Helmut64 0:0c31756924a2 143 tempa[j]=RoundKey[(i-1) * 4 + j];
Helmut64 0:0c31756924a2 144 }
Helmut64 0:0c31756924a2 145 if (i % Nk == 0)
Helmut64 0:0c31756924a2 146 {
Helmut64 0:0c31756924a2 147 // This function rotates the 4 bytes in a word to the left once.
Helmut64 0:0c31756924a2 148 // [a0,a1,a2,a3] becomes [a1,a2,a3,a0]
Helmut64 0:0c31756924a2 149
Helmut64 0:0c31756924a2 150 // Function RotWord()
Helmut64 0:0c31756924a2 151 {
Helmut64 0:0c31756924a2 152 k = tempa[0];
Helmut64 0:0c31756924a2 153 tempa[0] = tempa[1];
Helmut64 0:0c31756924a2 154 tempa[1] = tempa[2];
Helmut64 0:0c31756924a2 155 tempa[2] = tempa[3];
Helmut64 0:0c31756924a2 156 tempa[3] = k;
Helmut64 0:0c31756924a2 157 }
Helmut64 0:0c31756924a2 158
Helmut64 0:0c31756924a2 159 // SubWord() is a function that takes a four-byte input word and
Helmut64 0:0c31756924a2 160 // applies the S-box to each of the four bytes to produce an output word.
Helmut64 0:0c31756924a2 161
Helmut64 0:0c31756924a2 162 // Function Subword()
Helmut64 0:0c31756924a2 163 {
Helmut64 0:0c31756924a2 164 tempa[0] = getSBoxValue(tempa[0]);
Helmut64 0:0c31756924a2 165 tempa[1] = getSBoxValue(tempa[1]);
Helmut64 0:0c31756924a2 166 tempa[2] = getSBoxValue(tempa[2]);
Helmut64 0:0c31756924a2 167 tempa[3] = getSBoxValue(tempa[3]);
Helmut64 0:0c31756924a2 168 }
Helmut64 0:0c31756924a2 169
Helmut64 0:0c31756924a2 170 tempa[0] = tempa[0] ^ Rcon[(i/Nk)-1];
Helmut64 0:0c31756924a2 171 }
Helmut64 0:0c31756924a2 172 else if (Nk > 6 && i % Nk == 4)
Helmut64 0:0c31756924a2 173 {
Helmut64 0:0c31756924a2 174 // Function Subword()
Helmut64 0:0c31756924a2 175 {
Helmut64 0:0c31756924a2 176 tempa[0] = getSBoxValue(tempa[0]);
Helmut64 0:0c31756924a2 177 tempa[1] = getSBoxValue(tempa[1]);
Helmut64 0:0c31756924a2 178 tempa[2] = getSBoxValue(tempa[2]);
Helmut64 0:0c31756924a2 179 tempa[3] = getSBoxValue(tempa[3]);
Helmut64 0:0c31756924a2 180 }
Helmut64 0:0c31756924a2 181 }
Helmut64 0:0c31756924a2 182 RoundKey[i * 4 + 0] = RoundKey[(i - Nk) * 4 + 0] ^ tempa[0];
Helmut64 0:0c31756924a2 183 RoundKey[i * 4 + 1] = RoundKey[(i - Nk) * 4 + 1] ^ tempa[1];
Helmut64 0:0c31756924a2 184 RoundKey[i * 4 + 2] = RoundKey[(i - Nk) * 4 + 2] ^ tempa[2];
Helmut64 0:0c31756924a2 185 RoundKey[i * 4 + 3] = RoundKey[(i - Nk) * 4 + 3] ^ tempa[3];
Helmut64 0:0c31756924a2 186 }
Helmut64 0:0c31756924a2 187 }
Helmut64 0:0c31756924a2 188
Helmut64 0:0c31756924a2 189 // This function adds the round key to state.
Helmut64 0:0c31756924a2 190 // The round key is added to the state by an XOR function.
Helmut64 0:0c31756924a2 191 static void AddRoundKey(AES_CTX *ctx, uint8_t round)
Helmut64 0:0c31756924a2 192 {
Helmut64 0:0c31756924a2 193 uint8_t i,j;
Helmut64 0:0c31756924a2 194 for(i=0;i<4;++i)
Helmut64 0:0c31756924a2 195 {
Helmut64 0:0c31756924a2 196 for(j = 0; j < 4; ++j)
Helmut64 0:0c31756924a2 197 {
Helmut64 0:0c31756924a2 198 (*state)[i][j] ^= RoundKey[round * Nb * 4 + i * Nb + j];
Helmut64 0:0c31756924a2 199 }
Helmut64 0:0c31756924a2 200 }
Helmut64 0:0c31756924a2 201 }
Helmut64 0:0c31756924a2 202
Helmut64 0:0c31756924a2 203 // The SubBytes Function Substitutes the values in the
Helmut64 0:0c31756924a2 204 // state matrix with values in an S-box.
Helmut64 0:0c31756924a2 205 static void SubBytes(AES_CTX *ctx)
Helmut64 0:0c31756924a2 206 {
Helmut64 0:0c31756924a2 207 uint8_t i, j;
Helmut64 0:0c31756924a2 208 for(i = 0; i < 4; ++i)
Helmut64 0:0c31756924a2 209 {
Helmut64 0:0c31756924a2 210 for(j = 0; j < 4; ++j)
Helmut64 0:0c31756924a2 211 {
Helmut64 0:0c31756924a2 212 (*state)[j][i] = getSBoxValue((*state)[j][i]);
Helmut64 0:0c31756924a2 213 }
Helmut64 0:0c31756924a2 214 }
Helmut64 0:0c31756924a2 215 }
Helmut64 0:0c31756924a2 216
Helmut64 0:0c31756924a2 217 // The ShiftRows() function shifts the rows in the state to the left.
Helmut64 0:0c31756924a2 218 // Each row is shifted with different offset.
Helmut64 0:0c31756924a2 219 // Offset = Row number. So the first row is not shifted.
Helmut64 0:0c31756924a2 220 static void ShiftRows(AES_CTX *ctx)
Helmut64 0:0c31756924a2 221 {
Helmut64 0:0c31756924a2 222 uint8_t temp;
Helmut64 0:0c31756924a2 223
Helmut64 0:0c31756924a2 224 // Rotate first row 1 columns to left
Helmut64 0:0c31756924a2 225 temp = (*state)[0][1];
Helmut64 0:0c31756924a2 226 (*state)[0][1] = (*state)[1][1];
Helmut64 0:0c31756924a2 227 (*state)[1][1] = (*state)[2][1];
Helmut64 0:0c31756924a2 228 (*state)[2][1] = (*state)[3][1];
Helmut64 0:0c31756924a2 229 (*state)[3][1] = temp;
Helmut64 0:0c31756924a2 230
Helmut64 0:0c31756924a2 231 // Rotate second row 2 columns to left
Helmut64 0:0c31756924a2 232 temp = (*state)[0][2];
Helmut64 0:0c31756924a2 233 (*state)[0][2] = (*state)[2][2];
Helmut64 0:0c31756924a2 234 (*state)[2][2] = temp;
Helmut64 0:0c31756924a2 235
Helmut64 0:0c31756924a2 236 temp = (*state)[1][2];
Helmut64 0:0c31756924a2 237 (*state)[1][2] = (*state)[3][2];
Helmut64 0:0c31756924a2 238 (*state)[3][2] = temp;
Helmut64 0:0c31756924a2 239
Helmut64 0:0c31756924a2 240 // Rotate third row 3 columns to left
Helmut64 0:0c31756924a2 241 temp = (*state)[0][3];
Helmut64 0:0c31756924a2 242 (*state)[0][3] = (*state)[3][3];
Helmut64 0:0c31756924a2 243 (*state)[3][3] = (*state)[2][3];
Helmut64 0:0c31756924a2 244 (*state)[2][3] = (*state)[1][3];
Helmut64 0:0c31756924a2 245 (*state)[1][3] = temp;
Helmut64 0:0c31756924a2 246 }
Helmut64 0:0c31756924a2 247
Helmut64 0:0c31756924a2 248 static uint8_t xtime(uint8_t x)
Helmut64 0:0c31756924a2 249 {
Helmut64 0:0c31756924a2 250 return ((x<<1) ^ (((x>>7) & 1) * 0x1b));
Helmut64 0:0c31756924a2 251 }
Helmut64 0:0c31756924a2 252
Helmut64 0:0c31756924a2 253 // MixColumns function mixes the columns of the state matrix
Helmut64 0:0c31756924a2 254 static void MixColumns(AES_CTX *ctx)
Helmut64 0:0c31756924a2 255 {
Helmut64 0:0c31756924a2 256 uint8_t i;
Helmut64 0:0c31756924a2 257 uint8_t Tmp,Tm,t;
Helmut64 0:0c31756924a2 258 for(i = 0; i < 4; ++i)
Helmut64 0:0c31756924a2 259 {
Helmut64 0:0c31756924a2 260 t = (*state)[i][0];
Helmut64 0:0c31756924a2 261 Tmp = (*state)[i][0] ^ (*state)[i][1] ^ (*state)[i][2] ^ (*state)[i][3] ;
Helmut64 0:0c31756924a2 262 Tm = (*state)[i][0] ^ (*state)[i][1] ; Tm = xtime(Tm); (*state)[i][0] ^= Tm ^ Tmp ;
Helmut64 0:0c31756924a2 263 Tm = (*state)[i][1] ^ (*state)[i][2] ; Tm = xtime(Tm); (*state)[i][1] ^= Tm ^ Tmp ;
Helmut64 0:0c31756924a2 264 Tm = (*state)[i][2] ^ (*state)[i][3] ; Tm = xtime(Tm); (*state)[i][2] ^= Tm ^ Tmp ;
Helmut64 0:0c31756924a2 265 Tm = (*state)[i][3] ^ t ; Tm = xtime(Tm); (*state)[i][3] ^= Tm ^ Tmp ;
Helmut64 0:0c31756924a2 266 }
Helmut64 0:0c31756924a2 267 }
Helmut64 0:0c31756924a2 268
Helmut64 0:0c31756924a2 269 // Multiply is used to multiply numbers in the field GF(2^8)
Helmut64 0:0c31756924a2 270 #if MULTIPLY_AS_A_FUNCTION
Helmut64 0:0c31756924a2 271 static uint8_t Multiply(uint8_t x, uint8_t y)
Helmut64 0:0c31756924a2 272 {
Helmut64 0:0c31756924a2 273 return (((y & 1) * x) ^
Helmut64 0:0c31756924a2 274 ((y>>1 & 1) * xtime(x)) ^
Helmut64 0:0c31756924a2 275 ((y>>2 & 1) * xtime(xtime(x))) ^
Helmut64 0:0c31756924a2 276 ((y>>3 & 1) * xtime(xtime(xtime(x)))) ^
Helmut64 0:0c31756924a2 277 ((y>>4 & 1) * xtime(xtime(xtime(xtime(x))))));
Helmut64 0:0c31756924a2 278 }
Helmut64 0:0c31756924a2 279 #else
Helmut64 0:0c31756924a2 280 #define Multiply(x, y) \
Helmut64 0:0c31756924a2 281 ( ((y & 1) * x) ^ \
Helmut64 0:0c31756924a2 282 ((y>>1 & 1) * xtime(x)) ^ \
Helmut64 0:0c31756924a2 283 ((y>>2 & 1) * xtime(xtime(x))) ^ \
Helmut64 0:0c31756924a2 284 ((y>>3 & 1) * xtime(xtime(xtime(x)))) ^ \
Helmut64 0:0c31756924a2 285 ((y>>4 & 1) * xtime(xtime(xtime(xtime(x)))))) \
Helmut64 0:0c31756924a2 286
Helmut64 0:0c31756924a2 287 #endif
Helmut64 0:0c31756924a2 288
Helmut64 0:0c31756924a2 289 // MixColumns function mixes the columns of the state matrix.
Helmut64 0:0c31756924a2 290 // The method used to multiply may be difficult to understand for the inexperienced.
Helmut64 0:0c31756924a2 291 // Please use the references to gain more information.
Helmut64 0:0c31756924a2 292 static void InvMixColumns(AES_CTX *ctx)
Helmut64 0:0c31756924a2 293 {
Helmut64 0:0c31756924a2 294 int i;
Helmut64 0:0c31756924a2 295 uint8_t a,b,c,d;
Helmut64 0:0c31756924a2 296 for(i=0;i<4;++i)
Helmut64 0:0c31756924a2 297 {
Helmut64 0:0c31756924a2 298 a = (*state)[i][0];
Helmut64 0:0c31756924a2 299 b = (*state)[i][1];
Helmut64 0:0c31756924a2 300 c = (*state)[i][2];
Helmut64 0:0c31756924a2 301 d = (*state)[i][3];
Helmut64 0:0c31756924a2 302
Helmut64 0:0c31756924a2 303 (*state)[i][0] = Multiply(a, 0x0e) ^ Multiply(b, 0x0b) ^ Multiply(c, 0x0d) ^ Multiply(d, 0x09);
Helmut64 0:0c31756924a2 304 (*state)[i][1] = Multiply(a, 0x09) ^ Multiply(b, 0x0e) ^ Multiply(c, 0x0b) ^ Multiply(d, 0x0d);
Helmut64 0:0c31756924a2 305 (*state)[i][2] = Multiply(a, 0x0d) ^ Multiply(b, 0x09) ^ Multiply(c, 0x0e) ^ Multiply(d, 0x0b);
Helmut64 0:0c31756924a2 306 (*state)[i][3] = Multiply(a, 0x0b) ^ Multiply(b, 0x0d) ^ Multiply(c, 0x09) ^ Multiply(d, 0x0e);
Helmut64 0:0c31756924a2 307 }
Helmut64 0:0c31756924a2 308 }
Helmut64 0:0c31756924a2 309
Helmut64 0:0c31756924a2 310
Helmut64 0:0c31756924a2 311 // The SubBytes Function Substitutes the values in the
Helmut64 0:0c31756924a2 312 // state matrix with values in an S-box.
Helmut64 0:0c31756924a2 313 static void InvSubBytes(AES_CTX *ctx)
Helmut64 0:0c31756924a2 314 {
Helmut64 0:0c31756924a2 315 uint8_t i,j;
Helmut64 0:0c31756924a2 316 for(i=0;i<4;++i)
Helmut64 0:0c31756924a2 317 {
Helmut64 0:0c31756924a2 318 for(j=0;j<4;++j)
Helmut64 0:0c31756924a2 319 {
Helmut64 0:0c31756924a2 320 (*state)[j][i] = getSBoxInvert((*state)[j][i]);
Helmut64 0:0c31756924a2 321 }
Helmut64 0:0c31756924a2 322 }
Helmut64 0:0c31756924a2 323 }
Helmut64 0:0c31756924a2 324
Helmut64 0:0c31756924a2 325 static void InvShiftRows(AES_CTX *ctx)
Helmut64 0:0c31756924a2 326 {
Helmut64 0:0c31756924a2 327 uint8_t temp;
Helmut64 0:0c31756924a2 328
Helmut64 0:0c31756924a2 329 // Rotate first row 1 columns to right
Helmut64 0:0c31756924a2 330 temp=(*state)[3][1];
Helmut64 0:0c31756924a2 331 (*state)[3][1]=(*state)[2][1];
Helmut64 0:0c31756924a2 332 (*state)[2][1]=(*state)[1][1];
Helmut64 0:0c31756924a2 333 (*state)[1][1]=(*state)[0][1];
Helmut64 0:0c31756924a2 334 (*state)[0][1]=temp;
Helmut64 0:0c31756924a2 335
Helmut64 0:0c31756924a2 336 // Rotate second row 2 columns to right
Helmut64 0:0c31756924a2 337 temp=(*state)[0][2];
Helmut64 0:0c31756924a2 338 (*state)[0][2]=(*state)[2][2];
Helmut64 0:0c31756924a2 339 (*state)[2][2]=temp;
Helmut64 0:0c31756924a2 340
Helmut64 0:0c31756924a2 341 temp=(*state)[1][2];
Helmut64 0:0c31756924a2 342 (*state)[1][2]=(*state)[3][2];
Helmut64 0:0c31756924a2 343 (*state)[3][2]=temp;
Helmut64 0:0c31756924a2 344
Helmut64 0:0c31756924a2 345 // Rotate third row 3 columns to right
Helmut64 0:0c31756924a2 346 temp=(*state)[0][3];
Helmut64 0:0c31756924a2 347 (*state)[0][3]=(*state)[1][3];
Helmut64 0:0c31756924a2 348 (*state)[1][3]=(*state)[2][3];
Helmut64 0:0c31756924a2 349 (*state)[2][3]=(*state)[3][3];
Helmut64 0:0c31756924a2 350 (*state)[3][3]=temp;
Helmut64 0:0c31756924a2 351 }
Helmut64 0:0c31756924a2 352
Helmut64 0:0c31756924a2 353
Helmut64 0:0c31756924a2 354 // Cipher is the main function that encrypts the PlainText.
Helmut64 0:0c31756924a2 355 static void Cipher(AES_CTX *ctx)
Helmut64 0:0c31756924a2 356 {
Helmut64 0:0c31756924a2 357 uint8_t round = 0;
Helmut64 0:0c31756924a2 358
Helmut64 0:0c31756924a2 359 // Add the First round key to the state before starting the rounds.
Helmut64 0:0c31756924a2 360 AddRoundKey(ctx, 0);
Helmut64 0:0c31756924a2 361
Helmut64 0:0c31756924a2 362 // There will be Nr rounds.
Helmut64 0:0c31756924a2 363 // The first Nr-1 rounds are identical.
Helmut64 0:0c31756924a2 364 // These Nr-1 rounds are executed in the loop below.
Helmut64 0:0c31756924a2 365 for(round = 1; round < Nr; ++round)
Helmut64 0:0c31756924a2 366 {
Helmut64 0:0c31756924a2 367 SubBytes(ctx);
Helmut64 0:0c31756924a2 368 ShiftRows(ctx);
Helmut64 0:0c31756924a2 369 MixColumns(ctx);
Helmut64 0:0c31756924a2 370 AddRoundKey(ctx, round);
Helmut64 0:0c31756924a2 371 }
Helmut64 0:0c31756924a2 372
Helmut64 0:0c31756924a2 373 // The last round is given below.
Helmut64 0:0c31756924a2 374 // The MixColumns function is not here in the last round.
Helmut64 0:0c31756924a2 375 SubBytes(ctx);
Helmut64 0:0c31756924a2 376 ShiftRows(ctx);
Helmut64 0:0c31756924a2 377 AddRoundKey(ctx, Nr);
Helmut64 0:0c31756924a2 378 }
Helmut64 0:0c31756924a2 379
Helmut64 0:0c31756924a2 380 static void InvCipher(AES_CTX *ctx)
Helmut64 0:0c31756924a2 381 {
Helmut64 0:0c31756924a2 382 uint8_t round=0;
Helmut64 0:0c31756924a2 383
Helmut64 0:0c31756924a2 384 // Add the First round key to the state before starting the rounds.
Helmut64 0:0c31756924a2 385 AddRoundKey(ctx, Nr);
Helmut64 0:0c31756924a2 386
Helmut64 0:0c31756924a2 387 // There will be Nr rounds.
Helmut64 0:0c31756924a2 388 // The first Nr-1 rounds are identical.
Helmut64 0:0c31756924a2 389 // These Nr-1 rounds are executed in the loop below.
Helmut64 0:0c31756924a2 390 for(round=Nr-1;round>0;round--)
Helmut64 0:0c31756924a2 391 {
Helmut64 0:0c31756924a2 392 InvShiftRows(ctx);
Helmut64 0:0c31756924a2 393 InvSubBytes(ctx);
Helmut64 0:0c31756924a2 394 AddRoundKey(ctx, round);
Helmut64 0:0c31756924a2 395 InvMixColumns(ctx);
Helmut64 0:0c31756924a2 396 }
Helmut64 0:0c31756924a2 397
Helmut64 0:0c31756924a2 398 // The last round is given below.
Helmut64 0:0c31756924a2 399 // The MixColumns function is not here in the last round.
Helmut64 0:0c31756924a2 400 InvShiftRows(ctx);
Helmut64 0:0c31756924a2 401 InvSubBytes(ctx);
Helmut64 0:0c31756924a2 402 AddRoundKey(ctx, 0);
Helmut64 0:0c31756924a2 403 }
Helmut64 0:0c31756924a2 404
Helmut64 0:0c31756924a2 405
Helmut64 0:0c31756924a2 406 /*****************************************************************************/
Helmut64 0:0c31756924a2 407 /* Public functions: */
Helmut64 0:0c31756924a2 408 /*****************************************************************************/
Helmut64 0:0c31756924a2 409
Helmut64 0:0c31756924a2 410
Helmut64 0:0c31756924a2 411 void AES128_InitContext(AES_CTX *ctx, const uint8_t* key, const uint8_t* initialVector)
Helmut64 0:0c31756924a2 412 {
Helmut64 0:0c31756924a2 413 // The KeyExpansion routine must be called before encryption.
Helmut64 0:0c31756924a2 414 KeyExpansion(ctx, key);
Helmut64 0:0c31756924a2 415 if (initialVector)
Helmut64 0:0c31756924a2 416 memcpy(ctx->InitialVector, initialVector, KEYLEN);
Helmut64 0:0c31756924a2 417
Helmut64 0:0c31756924a2 418 }
Helmut64 0:0c31756924a2 419 #ifdef ECB_MODE
Helmut64 0:0c31756924a2 420
Helmut64 0:0c31756924a2 421
Helmut64 0:0c31756924a2 422 void AES128_ECB_encrypt(AES_CTX *ctx, const uint8_t* input, uint8_t* output)
Helmut64 0:0c31756924a2 423 {
Helmut64 0:0c31756924a2 424 // Copy input to output, and work in-memory on output
Helmut64 0:0c31756924a2 425 memcpy(output, input, KEYLEN);
Helmut64 0:0c31756924a2 426 state = (state_t*)output;
Helmut64 0:0c31756924a2 427
Helmut64 0:0c31756924a2 428 // The next function call encrypts the PlainText with the Key using AES algorithm.
Helmut64 0:0c31756924a2 429 Cipher(ctx);
Helmut64 0:0c31756924a2 430 }
Helmut64 0:0c31756924a2 431
Helmut64 0:0c31756924a2 432 void AES128_ECB_decrypt(AES_CTX *ctx, const uint8_t* input, uint8_t *output)
Helmut64 0:0c31756924a2 433 {
Helmut64 0:0c31756924a2 434 // Copy input to output, and work in-memory on output
Helmut64 0:0c31756924a2 435 memcpy(output, input, KEYLEN);
Helmut64 0:0c31756924a2 436 state = (state_t*)output;
Helmut64 0:0c31756924a2 437
Helmut64 0:0c31756924a2 438 InvCipher(ctx);
Helmut64 0:0c31756924a2 439 }
Helmut64 0:0c31756924a2 440
Helmut64 0:0c31756924a2 441
Helmut64 0:0c31756924a2 442 #endif // ECB_MODE
Helmut64 0:0c31756924a2 443
Helmut64 0:0c31756924a2 444
Helmut64 0:0c31756924a2 445
Helmut64 0:0c31756924a2 446
Helmut64 0:0c31756924a2 447 #ifdef CBC_MODE
Helmut64 0:0c31756924a2 448
Helmut64 0:0c31756924a2 449
Helmut64 0:0c31756924a2 450 static void XorWithIv(AES_CTX *ctx, uint8_t* buf)
Helmut64 0:0c31756924a2 451 {
Helmut64 0:0c31756924a2 452 if (sizeof(int) == 4) {
Helmut64 0:0c31756924a2 453 uint32_t *data = (uint32_t *)buf;
Helmut64 0:0c31756924a2 454 uint32_t *iVec = (uint32_t *)Iv;
Helmut64 0:0c31756924a2 455
Helmut64 0:0c31756924a2 456 *data++ ^= *iVec++;
Helmut64 0:0c31756924a2 457 *data++ ^= *iVec++;
Helmut64 0:0c31756924a2 458 *data++ ^= *iVec++;
Helmut64 0:0c31756924a2 459 *data++ ^= *iVec++;
Helmut64 0:0c31756924a2 460 } else {
Helmut64 0:0c31756924a2 461 uint8_t i;
Helmut64 0:0c31756924a2 462 for(i = 0; i < KEYLEN; ++i)
Helmut64 0:0c31756924a2 463 {
Helmut64 0:0c31756924a2 464 buf[i] ^= Iv[i];
Helmut64 0:0c31756924a2 465 }
Helmut64 0:0c31756924a2 466 }
Helmut64 0:0c31756924a2 467 }
Helmut64 0:0c31756924a2 468
Helmut64 0:0c31756924a2 469 void AES128_CBC_encrypt_buffer(AES_CTX *ctx, uint8_t* output, const uint8_t* input, uint32_t length)
Helmut64 0:0c31756924a2 470 {
Helmut64 0:0c31756924a2 471 uintptr_t i;
Helmut64 0:0c31756924a2 472 uint8_t remainders = length % KEYLEN; /* Remaining bytes in the last non-full block */
Helmut64 0:0c31756924a2 473
Helmut64 0:0c31756924a2 474
Helmut64 0:0c31756924a2 475 for(i = 0; i < length; i += KEYLEN)
Helmut64 0:0c31756924a2 476 {
Helmut64 0:0c31756924a2 477 memcpy(output, input, KEYLEN);
Helmut64 0:0c31756924a2 478 XorWithIv(ctx, output);
Helmut64 0:0c31756924a2 479 state = (state_t*)output;
Helmut64 0:0c31756924a2 480 Cipher(ctx);
Helmut64 0:0c31756924a2 481 memcpy(ctx->InitialVector, output, KEYLEN);
Helmut64 0:0c31756924a2 482 input += KEYLEN;
Helmut64 0:0c31756924a2 483 output += KEYLEN;
Helmut64 0:0c31756924a2 484 }
Helmut64 0:0c31756924a2 485
Helmut64 0:0c31756924a2 486 if(remainders)
Helmut64 0:0c31756924a2 487 {
Helmut64 0:0c31756924a2 488 memcpy(output, input, KEYLEN);
Helmut64 0:0c31756924a2 489 memset(output + remainders, 0, KEYLEN - remainders); /* add 0-padding */
Helmut64 0:0c31756924a2 490 state = (state_t*)output;
Helmut64 0:0c31756924a2 491 Cipher(ctx);
Helmut64 0:0c31756924a2 492 }
Helmut64 0:0c31756924a2 493 }
Helmut64 0:0c31756924a2 494
Helmut64 0:0c31756924a2 495 void AES128_CBC_decrypt_buffer(AES_CTX *ctx, uint8_t* output, const uint8_t* input, uint32_t length)
Helmut64 0:0c31756924a2 496 {
Helmut64 0:0c31756924a2 497 uintptr_t i;
Helmut64 0:0c31756924a2 498 uint8_t remainders = length % KEYLEN; /* Remaining bytes in the last non-full block */
Helmut64 0:0c31756924a2 499
Helmut64 0:0c31756924a2 500
Helmut64 0:0c31756924a2 501 for(i = 0; i < length; i += KEYLEN)
Helmut64 0:0c31756924a2 502 {
Helmut64 0:0c31756924a2 503 memcpy(output, input, KEYLEN);
Helmut64 0:0c31756924a2 504 state = (state_t*)output;
Helmut64 0:0c31756924a2 505 InvCipher(ctx);
Helmut64 0:0c31756924a2 506 XorWithIv(ctx, output);
Helmut64 0:0c31756924a2 507 memcpy(ctx->InitialVector, input, KEYLEN);
Helmut64 0:0c31756924a2 508 input += KEYLEN;
Helmut64 0:0c31756924a2 509 output += KEYLEN;
Helmut64 0:0c31756924a2 510 }
Helmut64 0:0c31756924a2 511
Helmut64 0:0c31756924a2 512 if(remainders)
Helmut64 0:0c31756924a2 513 {
Helmut64 0:0c31756924a2 514 memcpy(output, input, KEYLEN);
Helmut64 0:0c31756924a2 515 memset(output+remainders, 0, KEYLEN - remainders); /* add 0-padding */
Helmut64 0:0c31756924a2 516 state = (state_t*)output;
Helmut64 0:0c31756924a2 517 InvCipher(ctx);
Helmut64 0:0c31756924a2 518 }
Helmut64 0:0c31756924a2 519 }
Helmut64 0:0c31756924a2 520
Helmut64 0:0c31756924a2 521
Helmut64 0:0c31756924a2 522 #endif // CBC_MODE
Helmut64 0:0c31756924a2 523
Helmut64 0:0c31756924a2 524