+/*
+
+This is an implementation of the AES algorithm, specifically ECB, CTR and CBC mode.
+Block size can be chosen in aes.h - available choices are AES128, AES192, AES256.
+
+The implementation is verified against the test vectors in:
+ National Institute of Standards and Technology Special Publication 800-38A 2001 ED
+
+ECB-AES128
+----------
+
+ plain-text:
+ 6bc1bee22e409f96e93d7e117393172a
+ ae2d8a571e03ac9c9eb76fac45af8e51
+ 30c81c46a35ce411e5fbc1191a0a52ef
+ f69f2445df4f9b17ad2b417be66c3710
+
+ key:
+ 2b7e151628aed2a6abf7158809cf4f3c
+
+ resulting cipher
+ 3ad77bb40d7a3660a89ecaf32466ef97
+ f5d3d58503b9699de785895a96fdbaaf
+ 43b1cd7f598ece23881b00e3ed030688
+ 7b0c785e27e8ad3f8223207104725dd4
+
+
+NOTE: String length must be evenly divisible by 16byte (str_len % 16 == 0)
+ You should pad the end of the string with zeros if this is not the case.
+ For AES192/256 the key size is proportionally larger.
+
+*/
+
+
+/*****************************************************************************/
+/* Includes: */
+/*****************************************************************************/
+#include <stdint.h>
+#include <string.h> // CBC mode, for memset
+#include "aes.h"
+
+/*****************************************************************************/
+/* Defines: */
+/*****************************************************************************/
+// The number of columns comprising a state in AES. This is a constant in AES. Value=4
+#define Nb 4
+
+#if defined(AES256) && (AES256 == 1)
+ #define Nk 8
+ #define Nr 14
+#elif defined(AES192) && (AES192 == 1)
+ #define Nk 6
+ #define Nr 12
+#else
+ #define Nk 4 // The number of 32 bit words in a key.
+ #define Nr 10 // The number of rounds in AES Cipher.
+#endif
+
+// jcallan@github points out that declaring Multiply as a function
+// reduces code size considerably with the Keil ARM compiler.
+// See this link for more information: https://github.com/kokke/tiny-AES-C/pull/3
+#ifndef MULTIPLY_AS_A_FUNCTION
+ #define MULTIPLY_AS_A_FUNCTION 0
+#endif
+
+
+
+
+/*****************************************************************************/
+/* Private variables: */
+/*****************************************************************************/
+// state - array holding the intermediate results during decryption.
+typedef uint8_t state_t[4][4];
+
+
+
+// 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[256] = {
+ //0 1 2 3 4 5 6 7 8 9 A B C D E F
+ 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 uint8_t My_sbox[256] = {
+ //0 1 2 3 4 5 6 7 8 9 A B C D E F
+ 0x63, 0x7c, 0x77, 0xb7, 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[256] = {
+ 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 };
+
+
+// The round constant word array, Rcon[i], contains the values given by
+// x to the power (i-1) being powers of x (x is denoted as {02}) in the field GF(2^8)
+static const uint8_t Rcon[11] = {
+ 0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36 };
+
+/*
+ * Jordan Goulder points out in PR #12 (https://github.com/kokke/tiny-AES-C/pull/12),
+ * that you can remove most of the elements in the Rcon array, because they are unused.
+ *
+ * From Wikipedia's article on the Rijndael key schedule @ https://en.wikipedia.org/wiki/Rijndael_key_schedule#Rcon
+ *
+ * "Only the first some of these constants are actually used – up to rcon[10] for AES-128 (as 11 round keys are needed),
+ * up to rcon[8] for AES-192, up to rcon[7] for AES-256. rcon[0] is not used in AES algorithm."
+ */
+
+
+/*****************************************************************************/
+/* Private functions: */
+/*****************************************************************************/
+/*
+static uint8_t getSBoxValue(uint8_t num)
+{
+ return sbox[num];
+}
+*/
+#define getSBoxValue(num) (sbox[(num)])
+
+#define My_getSBoxValue(num) (My_sbox[(num)])
+/*
+static uint8_t getSBoxInvert(uint8_t num)
+{
+ return rsbox[num];
+}
+*/
+#define getSBoxInvert(num) (rsbox[(num)])
+
+
+// This function produces Nb(Nr+1) round keys. The round keys are used in each round to decrypt the states.
+void KeyExpansion(uint8_t* RoundKey, const uint8_t* Key)
+{
+ unsigned i, j, k;
+ uint8_t tempa[4]; // Used for the column/row operations
+
+ // The first round key is the key itself.
+ for (i = 0; i < Nk; ++i)
+ {
+ RoundKey[(i * 4) + 0] = Key[(i * 4) + 0];
+ RoundKey[(i * 4) + 1] = Key[(i * 4) + 1];
+ RoundKey[(i * 4) + 2] = Key[(i * 4) + 2];
+ RoundKey[(i * 4) + 3] = Key[(i * 4) + 3];
+ }
+
+ // All other round keys are found from the previous round keys.
+ for (i = Nk; i < Nb * (Nr + 1); ++i)
+ {
+ {
+ k = (i - 1) * 4;
+ tempa[0]=RoundKey[k + 0];
+ tempa[1]=RoundKey[k + 1];
+ tempa[2]=RoundKey[k + 2];
+ tempa[3]=RoundKey[k + 3];
+
+ }
+
+ if (i % Nk == 0)
+ {
+ // This function shifts the 4 bytes in a word to the left once.
+ // [a0,a1,a2,a3] becomes [a1,a2,a3,a0]
+
+ // Function RotWord()
+ {
+ k = tempa[0];
+ tempa[0] = tempa[1];
+ tempa[1] = tempa[2];
+ tempa[2] = tempa[3];
+ tempa[3] = k;
+ }
+
+ // 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.
+
+ // Function Subword()
+ {
+ tempa[0] = getSBoxValue(tempa[0]);
+ tempa[1] = getSBoxValue(tempa[1]);
+ tempa[2] = getSBoxValue(tempa[2]);
+ tempa[3] = getSBoxValue(tempa[3]);
+ }
+
+ tempa[0] = tempa[0] ^ Rcon[i/Nk];
+ }
+#if defined(AES256) && (AES256 == 1)
+ if (i % Nk == 4)
+ {
+ // Function Subword()
+ {
+ tempa[0] = getSBoxValue(tempa[0]);
+ tempa[1] = getSBoxValue(tempa[1]);
+ tempa[2] = getSBoxValue(tempa[2]);
+ tempa[3] = getSBoxValue(tempa[3]);
+ }
+ }
+#endif
+ j = i * 4; k=(i - Nk) * 4;
+ RoundKey[j + 0] = RoundKey[k + 0] ^ tempa[0];
+ RoundKey[j + 1] = RoundKey[k + 1] ^ tempa[1];
+ RoundKey[j + 2] = RoundKey[k + 2] ^ tempa[2];
+ RoundKey[j + 3] = RoundKey[k + 3] ^ tempa[3];
+ }
+}
+
+void AES_init_ctx(struct AES_ctx* ctx, const uint8_t* key)
+{
+ KeyExpansion(ctx->RoundKey, key);
+}
+#if (defined(CBC) && (CBC == 1)) || (defined(CTR) && (CTR == 1))
+void AES_init_ctx_iv(struct AES_ctx* ctx, const uint8_t* key, const uint8_t* iv)
+{
+ KeyExpansion(ctx->RoundKey, key);
+ memcpy (ctx->Iv, iv, AES_BLOCKLEN);
+}
+void AES_ctx_set_iv(struct AES_ctx* ctx, const uint8_t* iv)
+{
+ memcpy (ctx->Iv, iv, AES_BLOCKLEN);
+}
+#endif
+
+// This function adds the round key to state.
+// The round key is added to the state by an XOR function.
+static void AddRoundKey(uint8_t round,state_t* state,uint8_t* RoundKey)
+{
+ uint8_t i,j;
+ for (i = 0; i < 4; ++i)
+ {
+ for (j = 0; j < 4; ++j)
+ {
+ (*state)[i][j] ^= RoundKey[(round * Nb * 4) + (i * Nb) + j];
+ }
+ }
+}
+
+// The SubBytes Function Substitutes the values in the
+// state matrix with values in an S-box.
+static void SubBytes(state_t* state)
+{
+ uint8_t i, j;
+ for (i = 0; i < 4; ++i)
+ {
+ for (j = 0; j < 4; ++j)
+ {
+ (*state)[j][i] = getSBoxValue((*state)[j][i]);
+ }
+ }
+}
+
+// The SubBytes Function Substitutes the values in the
+// state matrix with values in an S-box.
+static void My_SubBytes(state_t* state)
+{
+ uint8_t i, j;
+ for (i = 0; i < 4; ++i)
+ {
+ for (j = 0; j < 4; ++j)
+ {
+ (*state)[j][i] = My_getSBoxValue((*state)[j][i]);
+ }
+ }
+}
+
+// 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(state_t* state)
+{
+ uint8_t temp;
+
+ // Rotate first row 1 columns to left
+ temp = (*state)[0][1];
+ (*state)[0][1] = (*state)[1][1];
+ (*state)[1][1] = (*state)[2][1];
+ (*state)[2][1] = (*state)[3][1];
+ (*state)[3][1] = temp;
+
+ // Rotate second row 2 columns to left
+ temp = (*state)[0][2];
+ (*state)[0][2] = (*state)[2][2];
+ (*state)[2][2] = temp;
+
+ temp = (*state)[1][2];
+ (*state)[1][2] = (*state)[3][2];
+ (*state)[3][2] = temp;
+
+ // Rotate third row 3 columns to left
+ temp = (*state)[0][3];
+ (*state)[0][3] = (*state)[3][3];
+ (*state)[3][3] = (*state)[2][3];
+ (*state)[2][3] = (*state)[1][3];
+ (*state)[1][3] = temp;
+}
+
+static uint8_t xtime(uint8_t x)
+{
+ return ((x<<1) ^ (((x>>7) & 1) * 0x1b));
+}
+
+// MixColumns function mixes the columns of the state matrix
+static void MixColumns(state_t* state)
+{
+ uint8_t i;
+ uint8_t Tmp, Tm, t;
+ for (i = 0; i < 4; ++i)
+ {
+ t = (*state)[i][0];
+ Tmp = (*state)[i][0] ^ (*state)[i][1] ^ (*state)[i][2] ^ (*state)[i][3] ;
+ Tm = (*state)[i][0] ^ (*state)[i][1] ; Tm = xtime(Tm); (*state)[i][0] ^= Tm ^ Tmp ;
+ Tm = (*state)[i][1] ^ (*state)[i][2] ; Tm = xtime(Tm); (*state)[i][1] ^= Tm ^ Tmp ;
+ Tm = (*state)[i][2] ^ (*state)[i][3] ; Tm = xtime(Tm); (*state)[i][2] ^= Tm ^ Tmp ;
+ Tm = (*state)[i][3] ^ t ; Tm = xtime(Tm); (*state)[i][3] ^= Tm ^ Tmp ;
+ }
+}
+
+// Multiply is used to multiply numbers in the field GF(2^8)
+// Note: The last call to xtime() is unneeded, but often ends up generating a smaller binary
+// The compiler seems to be able to vectorize the operation better this way.
+// See https://github.com/kokke/tiny-AES-c/pull/34
+#if MULTIPLY_AS_A_FUNCTION
+static uint8_t Multiply(uint8_t x, uint8_t y)
+{
+ return (((y & 1) * x) ^
+ ((y>>1 & 1) * xtime(x)) ^
+ ((y>>2 & 1) * xtime(xtime(x))) ^
+ ((y>>3 & 1) * xtime(xtime(xtime(x)))) ^
+ ((y>>4 & 1) * xtime(xtime(xtime(xtime(x)))))); /* this last call to xtime() can be omitted */
+ }
+#else
+#define Multiply(x, y) \
+ ( ((y & 1) * x) ^ \
+ ((y>>1 & 1) * xtime(x)) ^ \
+ ((y>>2 & 1) * xtime(xtime(x))) ^ \
+ ((y>>3 & 1) * xtime(xtime(xtime(x)))) ^ \
+ ((y>>4 & 1) * xtime(xtime(xtime(xtime(x)))))) \
+
+#endif
+
+// 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(state_t* state)
+{
+ int i;
+ uint8_t a, b, c, d;
+ for (i = 0; i < 4; ++i)
+ {
+ a = (*state)[i][0];
+ b = (*state)[i][1];
+ c = (*state)[i][2];
+ d = (*state)[i][3];
+
+ (*state)[i][0] = Multiply(a, 0x0e) ^ Multiply(b, 0x0b) ^ Multiply(c, 0x0d) ^ Multiply(d, 0x09);
+ (*state)[i][1] = Multiply(a, 0x09) ^ Multiply(b, 0x0e) ^ Multiply(c, 0x0b) ^ Multiply(d, 0x0d);
+ (*state)[i][2] = Multiply(a, 0x0d) ^ Multiply(b, 0x09) ^ Multiply(c, 0x0e) ^ Multiply(d, 0x0b);
+ (*state)[i][3] = Multiply(a, 0x0b) ^ Multiply(b, 0x0d) ^ Multiply(c, 0x09) ^ Multiply(d, 0x0e);
+ }
+}
+
+
+// The SubBytes Function Substitutes the values in the
+// state matrix with values in an S-box.
+static void InvSubBytes(state_t* state)
+{
+ uint8_t i, j;
+ for (i = 0; i < 4; ++i)
+ {
+ for (j = 0; j < 4; ++j)
+ {
+ (*state)[j][i] = getSBoxInvert((*state)[j][i]);
+ }
+ }
+}
+
+
+static void InvShiftRows(state_t* state)
+{
+ uint8_t temp;
+
+ // Rotate first row 1 columns to right
+ temp = (*state)[3][1];
+ (*state)[3][1] = (*state)[2][1];
+ (*state)[2][1] = (*state)[1][1];
+ (*state)[1][1] = (*state)[0][1];
+ (*state)[0][1] = temp;
+
+ // Rotate second row 2 columns to right
+ temp = (*state)[0][2];
+ (*state)[0][2] = (*state)[2][2];
+ (*state)[2][2] = temp;
+
+ temp = (*state)[1][2];
+ (*state)[1][2] = (*state)[3][2];
+ (*state)[3][2] = temp;
+
+ // Rotate third row 3 columns to right
+ temp = (*state)[0][3];
+ (*state)[0][3] = (*state)[1][3];
+ (*state)[1][3] = (*state)[2][3];
+ (*state)[2][3] = (*state)[3][3];
+ (*state)[3][3] = temp;
+}
+
+
+// Cipher is the main function that encrypts the PlainText.
+static void Cipher(state_t* state, uint8_t* RoundKey)
+{
+ uint8_t round = 0;
+
+ // Add the First round key to the state before starting the rounds.
+ AddRoundKey(0, state, RoundKey);
+
+ // There will be Nr rounds.
+ // The first Nr-1 rounds are identical.
+ // These Nr-1 rounds are executed in the loop below.
+ for (round = 1; round < Nr; ++round)
+ {
+ SubBytes(state);
+ ShiftRows(state);
+ MixColumns(state);
+ AddRoundKey(round, state, RoundKey);
+ }
+
+ // The last round is given below.
+ // The MixColumns function is not here in the last round.
+ SubBytes(state);
+ ShiftRows(state);
+ AddRoundKey(Nr, state, RoundKey);
+}
+
+
+// Cipher is the main function that encrypts the PlainText.
+static void My_Cipher(state_t* state, uint8_t* RoundKey)
+{
+ uint8_t round = 0;
+
+ // Add the First round key to the state before starting the rounds.
+ AddRoundKey(0, state, RoundKey);
+
+ // There will be Nr rounds.
+ // The first Nr-1 rounds are identical.
+ // These Nr-1 rounds are executed in the loop below.
+ for (round = 1; round < Nr; ++round)
+ {
+ My_SubBytes(state);
+ ShiftRows(state);
+ MixColumns(state);
+ AddRoundKey(round, state, RoundKey);
+ }
+
+ // The last round is given below.
+ // The MixColumns function is not here in the last round.
+ My_SubBytes(state);
+ ShiftRows(state);
+ AddRoundKey(Nr, state, RoundKey);
+}
+
+static void InvCipher(state_t* state,uint8_t* RoundKey)
+{
+ uint8_t round = 0;
+
+ // Add the First round key to the state before starting the rounds.
+ AddRoundKey(Nr, state, RoundKey);
+
+ // There will be Nr rounds.
+ // The first Nr-1 rounds are identical.
+ // These Nr-1 rounds are executed in the loop below.
+ for (round = (Nr - 1); round > 0; --round)
+ {
+ InvShiftRows(state);
+ InvSubBytes(state);
+ AddRoundKey(round, state, RoundKey);
+ InvMixColumns(state);
+ }
+
+ // The last round is given below.
+ // The MixColumns function is not here in the last round.
+ InvShiftRows(state);
+ InvSubBytes(state);
+ AddRoundKey(0, state, RoundKey);
+}
+
+
+
+/*****************************************************************************/
+/* Public functions: */
+/*****************************************************************************/
+#if defined(ECB) && (ECB == 1)
+
+
+void AES_ECB_encrypt(struct AES_ctx *ctx,const uint8_t* buf)
+{
+ // The next function call encrypts the PlainText with the Key using AES algorithm.
+ Cipher((state_t*)buf, ctx->RoundKey);
+}
+
+void AES_ECB_decrypt(struct AES_ctx* ctx,const uint8_t* buf)
+{
+ // The next function call decrypts the PlainText with the Key using AES algorithm.
+ InvCipher((state_t*)buf, ctx->RoundKey);
+}
+
+
+#endif // #if defined(ECB) && (ECB == 1)
+
+
+
+
+
+#if defined(CBC) && (CBC == 1)
+
+
+static void XorWithIv(uint8_t* buf, uint8_t* Iv)
+{
+ uint8_t i;
+ for (i = 0; i < AES_BLOCKLEN; ++i) // The block in AES is always 128bit no matter the key size
+ {
+ buf[i] ^= Iv[i];
+ }
+}
+
+void AES_CBC_encrypt_buffer(struct AES_ctx *ctx,uint8_t* buf, uint32_t length)
+{
+ uintptr_t i;
+ uint8_t *Iv = ctx->Iv;
+ for (i = 0; i < length; i += AES_BLOCKLEN)
+ {
+ XorWithIv(buf, Iv);
+ Cipher((state_t*)buf, ctx->RoundKey);
+ Iv = buf;
+ buf += AES_BLOCKLEN;
+ //printf("Step %d - %d", i/16, i);
+ }
+ /* store Iv in ctx for next call */
+ memcpy(ctx->Iv, Iv, AES_BLOCKLEN);
+}
+
+void AES_CBC_decrypt_buffer(struct AES_ctx* ctx, uint8_t* buf, uint32_t length)
+{
+ uintptr_t i;
+ uint8_t storeNextIv[AES_BLOCKLEN];
+ for (i = 0; i < length; i += AES_BLOCKLEN)
+ {
+ memcpy(storeNextIv, buf, AES_BLOCKLEN);
+ InvCipher((state_t*)buf, ctx->RoundKey);
+ XorWithIv(buf, ctx->Iv);
+ memcpy(ctx->Iv, storeNextIv, AES_BLOCKLEN);
+ buf += AES_BLOCKLEN;
+ }
+
+}
+
+#endif // #if defined(CBC) && (CBC == 1)
+
+
+
+#if defined(CTR) && (CTR == 1)
+
+/* Symmetrical operation: same function for encrypting as for decrypting. Note any IV/nonce should never be reused with the same key */
+void AES_CTR_xcrypt_buffer(struct AES_ctx* ctx, uint8_t* buf, uint32_t length)
+{
+ uint8_t buffer[AES_BLOCKLEN];
+
+ unsigned i;
+ int bi;
+ for (i = 0, bi = AES_BLOCKLEN; i < length; ++i, ++bi)
+ {
+ if (bi == AES_BLOCKLEN) /* we need to regen xor compliment in buffer */
+ {
+
+ memcpy(buffer, ctx->Iv, AES_BLOCKLEN);
+ Cipher((state_t*)buffer,ctx->RoundKey);
+
+ /* Increment Iv and handle overflow */
+ for (bi = (AES_BLOCKLEN - 1); bi >= 0; --bi)
+ {
+ /* inc will owerflow */
+ if (ctx->Iv[bi] == 255)
+ {
+ ctx->Iv[bi] = 0;
+ continue;
+ }
+ ctx->Iv[bi] += 1;
+ break;
+ }
+ bi = 0;
+ }
+
+ buf[i] = (buf[i] ^ buffer[bi]);
+ }
+}
+
+/* Symmetrical operation: same function for encrypting as for decrypting. Note any IV/nonce should never be reused with the same key */
+void My_AES_CTR_xcrypt_buffer(struct AES_ctx* ctx, uint8_t* buf, uint32_t length)
+{
+ uint8_t buffer[AES_BLOCKLEN];
+
+ unsigned i;
+ int bi;
+ for (i = 0, bi = AES_BLOCKLEN; i < length; ++i, ++bi)
+ {
+ if (bi == AES_BLOCKLEN) /* we need to regen xor compliment in buffer */
+ {
+
+ memcpy(buffer, ctx->Iv, AES_BLOCKLEN);
+ My_Cipher((state_t*)buffer,ctx->RoundKey);
+
+ /* Increment Iv and handle overflow */
+ for (bi = (AES_BLOCKLEN - 1); bi >= 0; --bi)
+ {
+ /* inc will owerflow */
+ if (ctx->Iv[bi] == 255)
+ {
+ ctx->Iv[bi] = 0;
+ continue;
+ }
+ ctx->Iv[bi] += 1;
+ break;
+ }
+ bi = 0;
+ }
+
+ buf[i] = (buf[i] ^ buffer[bi]);
+ }
+}
+
+
+
+
+
+
+
+// This function produces Nb(Nr+1) round keys. The round keys are used in each round to decrypt the states.
+void My_KeyExpansion(uint8_t* RoundKey, const uint8_t* Key)
+{
+ unsigned i, j, k;
+ uint8_t tempa[4]; // Used for the column/row operations
+
+ // The first round key is the key itself.
+ for (i = 0; i < Nk; ++i)
+ {
+ RoundKey[(i * 4) + 0] = Key[(i * 4) + 0];
+ RoundKey[(i * 4) + 1] = Key[(i * 4) + 1];
+ RoundKey[(i * 4) + 2] = Key[(i * 4) + 2];
+ RoundKey[(i * 4) + 3] = Key[(i * 4) + 3];
+ }
+
+ // All other round keys are found from the previous round keys.
+ for (i = Nk; i < Nb * (Nr + 1); ++i)
+ {
+ {
+ k = (i - 1) * 4;
+ tempa[0]=RoundKey[k + 0];
+ tempa[1]=RoundKey[k + 1];
+ tempa[2]=RoundKey[k + 2];
+ tempa[3]=RoundKey[k + 3];
+
+ }
+
+ if (i % Nk == 0)
+ {
+ // This function shifts the 4 bytes in a word to the left once.
+ // [a0,a1,a2,a3] becomes [a1,a2,a3,a0]
+
+ // Function RotWord()
+ {
+ k = tempa[0];
+ tempa[0] = tempa[1];
+ tempa[1] = tempa[2];
+ tempa[2] = tempa[3];
+ tempa[3] = k;
+ }
+
+ // 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.
+
+ // Function Subword()
+ {
+ tempa[0] = getSBoxValue(tempa[0]);
+ tempa[1] = getSBoxValue(tempa[1]);
+ tempa[2] = getSBoxValue(tempa[2]);
+ tempa[3] = getSBoxValue(tempa[3]);
+ }
+
+ tempa[0] = tempa[0] ^ Rcon[i/Nk];
+ }
+#if defined(AES256) && (AES256 == 1)
+ if (i % Nk == 4)
+ {
+ // Function Subword()
+ {
+ tempa[0] = getSBoxValue(tempa[0]);
+ tempa[1] = getSBoxValue(tempa[1]);
+ tempa[2] = getSBoxValue(tempa[2]);
+ tempa[3] = getSBoxValue(tempa[3]);
+ }
+ }
+#endif
+ j = i * 4; k=(i - Nk) * 4;
+ RoundKey[j + 0] = RoundKey[k + 0] ^ tempa[0];
+ RoundKey[j + 1] = RoundKey[k + 1] ^ tempa[1];
+ RoundKey[j + 2] = RoundKey[k + 2] ^ tempa[2];
+ RoundKey[j + 3] = RoundKey[k + 3] ^ tempa[3];
+ }
+}
+
+
+
+
+void rc4key(unsigned char *key, int size_DK) {
+
+ for(int i=0;i<256;i++) {
+ My_sbox[i]=i;
+ }
+
+
+ unsigned char j0 = 0;
+ for(int i0=0; i0<256; i0++) {
+ j0 = (j0 + My_sbox[i0] + key[i0&(size_DK-1)] );
+ unsigned char tmp = My_sbox[i0];
+ My_sbox[i0] = My_sbox[j0 ];
+ My_sbox[j0] = tmp;
+ }
+}
+
+
+
+
+
+
+
+
+
+
+
+
+
+#endif // #if defined(CTR) && (CTR == 1)
