[RFC PATCH 01/10] Import Tiny AES128
Anton Lundin
glance at acc.umu.se
Fri Nov 14 09:01:30 PST 2014
This imports Tiny AES128 from https://github.com/kokke/tiny-AES128-C for
use in the decoding of OSTC3 firmwares.
This aes-code is released into the public domain.
Signed-off-by: Anton Lundin <glance at acc.umu.se>
---
msvc/libdivecomputer.vcproj | 6 +
src/Makefile.am | 1 +
src/aes.c | 486 ++++++++++++++++++++++++++++++++++++++++++++
src/aes.h | 16 ++
4 files changed, 509 insertions(+)
create mode 100644 src/aes.c
create mode 100644 src/aes.h
diff --git a/msvc/libdivecomputer.vcproj b/msvc/libdivecomputer.vcproj
index 78a8190..10a4cf7 100644
--- a/msvc/libdivecomputer.vcproj
+++ b/msvc/libdivecomputer.vcproj
@@ -247,6 +247,9 @@
>
</File>
<File
+ RelativePath="..\src\aes.c"
+ >
+ <File
RelativePath="..\src\hw_ostc3.c"
>
</File>
@@ -537,6 +540,9 @@
>
</File>
<File
+ RelativePath="..\src\aes.h"
+ >
+ <File
RelativePath="..\include\libdivecomputer\hw_ostc3.h"
>
</File>
diff --git a/src/Makefile.am b/src/Makefile.am
index 595f0c7..eb39a4b 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -43,6 +43,7 @@ libdivecomputer_la_SOURCES = \
ihex.h ihex.c \
hw_ostc.c hw_ostc_parser.c \
hw_frog.c \
+ aes.h aes.c \
hw_ostc3.c \
cressi_edy.c cressi_edy_parser.c \
cressi_leonardo.c cressi_leonardo_parser.c \
diff --git a/src/aes.c b/src/aes.c
new file mode 100644
index 0000000..000a067
--- /dev/null
+++ b/src/aes.c
@@ -0,0 +1,486 @@
+/*
+
+This is an implementation of the AES128 algorithm, specifically ECB mode.
+
+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
+ 50fe67cc996d32b6da0937e99bafec60
+ d9a4dada0892239f6b8b3d7680e15674
+ a78819583f0308e7a6bf36b1386abf23
+ c6d3416d29165c6fcb8e51a227ba994e
+
+
+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.
+
+*/
+
+#ifndef _AES_C_
+#define _AES_C_
+
+
+/*****************************************************************************/
+/* Includes: */
+/*****************************************************************************/
+#include <stdint.h>
+#include "aes.h"
+
+
+/*****************************************************************************/
+/* Defines: */
+/*****************************************************************************/
+// The number of columns comprising a state in AES. This is a constant in AES. Value=4
+#define Nb 4
+// The number of 32 bit words in a key.
+#define Nk 4
+// Key length in bytes [128 bit]
+#define keyln 16
+// The number of rounds in AES Cipher.
+#define Nr 10
+
+
+/*****************************************************************************/
+/* Private variables: */
+/*****************************************************************************/
+// in - pointer to the CipherText to be decrypted.
+// out - pointer to buffer to hold output of the decryption.
+// state - array holding the intermediate results during decryption.
+static uint8_t* in, *out, state[4][4];
+
+// The array that stores the round keys.
+static uint8_t RoundKey[176];
+
+// The Key input to the AES Program
+static uint8_t* Key;
+
+// 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 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 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 1, not 0).
+static const uint8_t Rcon[255] = {
+ 0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a,
+ 0x2f, 0x5e, 0xbc, 0x63, 0xc6, 0x97, 0x35, 0x6a, 0xd4, 0xb3, 0x7d, 0xfa, 0xef, 0xc5, 0x91, 0x39,
+ 0x72, 0xe4, 0xd3, 0xbd, 0x61, 0xc2, 0x9f, 0x25, 0x4a, 0x94, 0x33, 0x66, 0xcc, 0x83, 0x1d, 0x3a,
+ 0x74, 0xe8, 0xcb, 0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36, 0x6c, 0xd8,
+ 0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc, 0x63, 0xc6, 0x97, 0x35, 0x6a, 0xd4, 0xb3, 0x7d, 0xfa, 0xef,
+ 0xc5, 0x91, 0x39, 0x72, 0xe4, 0xd3, 0xbd, 0x61, 0xc2, 0x9f, 0x25, 0x4a, 0x94, 0x33, 0x66, 0xcc,
+ 0x83, 0x1d, 0x3a, 0x74, 0xe8, 0xcb, 0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b,
+ 0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc, 0x63, 0xc6, 0x97, 0x35, 0x6a, 0xd4, 0xb3,
+ 0x7d, 0xfa, 0xef, 0xc5, 0x91, 0x39, 0x72, 0xe4, 0xd3, 0xbd, 0x61, 0xc2, 0x9f, 0x25, 0x4a, 0x94,
+ 0x33, 0x66, 0xcc, 0x83, 0x1d, 0x3a, 0x74, 0xe8, 0xcb, 0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20,
+ 0x40, 0x80, 0x1b, 0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc, 0x63, 0xc6, 0x97, 0x35,
+ 0x6a, 0xd4, 0xb3, 0x7d, 0xfa, 0xef, 0xc5, 0x91, 0x39, 0x72, 0xe4, 0xd3, 0xbd, 0x61, 0xc2, 0x9f,
+ 0x25, 0x4a, 0x94, 0x33, 0x66, 0xcc, 0x83, 0x1d, 0x3a, 0x74, 0xe8, 0xcb, 0x8d, 0x01, 0x02, 0x04,
+ 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc, 0x63,
+ 0xc6, 0x97, 0x35, 0x6a, 0xd4, 0xb3, 0x7d, 0xfa, 0xef, 0xc5, 0x91, 0x39, 0x72, 0xe4, 0xd3, 0xbd,
+ 0x61, 0xc2, 0x9f, 0x25, 0x4a, 0x94, 0x33, 0x66, 0xcc, 0x83, 0x1d, 0x3a, 0x74, 0xe8, 0xcb };
+
+
+/*****************************************************************************/
+/* Private functions: */
+/*****************************************************************************/
+static uint8_t getSBoxValue(uint8_t num)
+{
+ return sbox[num];
+}
+
+static uint8_t getSBoxInvert(uint8_t num)
+{
+ return rsbox[num];
+}
+
+
+// This function produces Nb(Nr+1) round keys. The round keys are used in each round to decrypt the states.
+static void KeyExpansion()
+{
+ uint32_t 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 < (Nb * (Nr + 1))); ++i)
+ {
+ for(j = 0; j < 4; ++j)
+ {
+ tempa[j]=RoundKey[(i-1) * 4 + j];
+ }
+ if (i % Nk == 0)
+ {
+ // This function rotates 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];
+ }
+ else if (Nk > 6 && 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]);
+ }
+ }
+ RoundKey[i * 4 + 0] = RoundKey[(i - Nk) * 4 + 0] ^ tempa[0];
+ RoundKey[i * 4 + 1] = RoundKey[(i - Nk) * 4 + 1] ^ tempa[1];
+ RoundKey[i * 4 + 2] = RoundKey[(i - Nk) * 4 + 2] ^ tempa[2];
+ RoundKey[i * 4 + 3] = RoundKey[(i - Nk) * 4 + 3] ^ tempa[3];
+ }
+}
+
+// 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)
+{
+ uint8_t i,j;
+ for(i=0;i<4;i++)
+ {
+ for(j = 0; j < 4; ++j)
+ {
+ state[j][i] ^= 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()
+{
+ uint8_t i, j;
+ for(i = 0; i < 4; ++i)
+ {
+ for(j = 0; j < 4; ++j)
+ {
+ state[i][j] = getSBoxValue(state[i][j]);
+ }
+ }
+}
+
+// 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()
+{
+ uint8_t temp;
+
+ // Rotate first row 1 columns to left
+ temp = state[1][0];
+ state[1][0] = state[1][1];
+ state[1][1] = state[1][2];
+ state[1][2] = state[1][3];
+ state[1][3] = temp;
+
+ // Rotate second row 2 columns to left
+ temp = state[2][0];
+ state[2][0] = state[2][2];
+ state[2][2] = temp;
+
+ temp = state[2][1];
+ state[2][1] = state[2][3];
+ state[2][3] = temp;
+
+ // Rotate third row 3 columns to left
+ temp = state[3][0];
+ state[3][0] = state[3][3];
+ state[3][3] = state[3][2];
+ state[3][2] = state[3][1];
+ state[3][1] = 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()
+{
+ uint8_t i;
+ uint8_t Tmp,Tm,t;
+ for(i = 0; i < 4; ++i)
+ {
+ t = state[0][i];
+ Tmp = state[0][i] ^ state[1][i] ^ state[2][i] ^ state[3][i] ;
+ Tm = state[0][i] ^ state[1][i] ; Tm = xtime(Tm); state[0][i] ^= Tm ^ Tmp ;
+ Tm = state[1][i] ^ state[2][i] ; Tm = xtime(Tm); state[1][i] ^= Tm ^ Tmp ;
+ Tm = state[2][i] ^ state[3][i] ; Tm = xtime(Tm); state[2][i] ^= Tm ^ Tmp ;
+ Tm = state[3][i] ^ t ; Tm = xtime(Tm); state[3][i] ^= Tm ^ Tmp ;
+ }
+}
+
+// Multiplty is a macro used to multiply numbers in the field GF(2^8)
+#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))))))
+
+
+// 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()
+{
+ int i;
+ uint8_t a,b,c,d;
+ for(i=0;i<4;i++)
+ {
+
+ a = state[0][i];
+ b = state[1][i];
+ c = state[2][i];
+ d = state[3][i];
+
+
+ state[0][i] = Multiply(a, 0x0e) ^ Multiply(b, 0x0b) ^ Multiply(c, 0x0d) ^ Multiply(d, 0x09);
+ state[1][i] = Multiply(a, 0x09) ^ Multiply(b, 0x0e) ^ Multiply(c, 0x0b) ^ Multiply(d, 0x0d);
+ state[2][i] = Multiply(a, 0x0d) ^ Multiply(b, 0x09) ^ Multiply(c, 0x0e) ^ Multiply(d, 0x0b);
+ state[3][i] = 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()
+{
+ uint8_t i,j;
+ for(i=0;i<4;i++)
+ {
+ for(j=0;j<4;j++)
+ {
+ state[i][j] = getSBoxInvert(state[i][j]);
+ }
+ }
+}
+
+
+static void InvShiftRows()
+{
+ uint8_t temp;
+
+ // Rotate first row 1 columns to right
+ temp=state[1][3];
+ state[1][3]=state[1][2];
+ state[1][2]=state[1][1];
+ state[1][1]=state[1][0];
+ state[1][0]=temp;
+
+ // Rotate second row 2 columns to right
+ temp=state[2][0];
+ state[2][0]=state[2][2];
+ state[2][2]=temp;
+
+ temp=state[2][1];
+ state[2][1]=state[2][3];
+ state[2][3]=temp;
+
+ // Rotate third row 3 columns to right
+ temp=state[3][0];
+ state[3][0]=state[3][1];
+ state[3][1]=state[3][2];
+ state[3][2]=state[3][3];
+ state[3][3]=temp;
+}
+
+
+// Cipher is the main function that encrypts the PlainText.
+static void Cipher()
+{
+ uint8_t i, j, round = 0;
+
+ //Copy the input PlainText to state array.
+ for(i = 0; i < 4; ++i)
+ {
+ for(j = 0; j < 4 ; ++j)
+ {
+ state[j][i] = in[(i * 4) + j];
+ }
+ }
+
+ // Add the First round key to the state before starting the rounds.
+ AddRoundKey(0);
+
+ // 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();
+ ShiftRows();
+ MixColumns();
+ AddRoundKey(round);
+ }
+
+ // The last round is given below.
+ // The MixColumns function is not here in the last round.
+ SubBytes();
+ ShiftRows();
+ AddRoundKey(Nr);
+
+ // The encryption process is over.
+ // Copy the state array to output array.
+ for(i = 0; i < 4; ++i)
+ {
+ for(j = 0; j < 4; ++j)
+ {
+ out[(i * 4) + j] = state[j][i];
+ }
+ }
+}
+
+static void InvCipher()
+{
+ uint8_t i,j,round=0;
+
+ //Copy the input CipherText to state array.
+ for(i=0;i<4;i++)
+ {
+ for(j=0;j<4;j++)
+ {
+ state[j][i] = in[i*4 + j];
+ }
+ }
+
+ // Add the First round key to the state before starting the rounds.
+ AddRoundKey(Nr);
+
+ // 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();
+ InvSubBytes();
+ AddRoundKey(round);
+ InvMixColumns();
+ }
+
+ // The last round is given below.
+ // The MixColumns function is not here in the last round.
+ InvShiftRows();
+ InvSubBytes();
+ AddRoundKey(0);
+
+ // The decryption process is over.
+ // Copy the state array to output array.
+ for(i=0;i<4;i++)
+ {
+ for(j=0;j<4;j++)
+ {
+ out[i*4+j]=state[j][i];
+ }
+ }
+}
+
+
+/*****************************************************************************/
+/* Public functions: */
+/*****************************************************************************/
+
+void AES128_ECB_encrypt(uint8_t* input, uint8_t* key, uint8_t *output)
+{
+ // Copy the Key and CipherText
+ Key = key;
+ in = input;
+ out = output;
+
+ // The KeyExpansion routine must be called before encryption.
+ KeyExpansion();
+
+ // The next function call encrypts the PlainText with the Key using AES algorithm.
+ Cipher();
+}
+
+void AES128_ECB_decrypt(uint8_t* input, uint8_t* key, uint8_t *output)
+{
+ Key = key;
+ in = input;
+ out = output;
+
+ KeyExpansion();
+
+ InvCipher();
+}
+
+#endif //_AES_C_
+
+
diff --git a/src/aes.h b/src/aes.h
new file mode 100644
index 0000000..5fb2176
--- /dev/null
+++ b/src/aes.h
@@ -0,0 +1,16 @@
+#ifndef _AES_H_
+#define _AES_H_
+
+#include <stdint.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif /* __cplusplus */
+
+void AES128_ECB_encrypt(uint8_t* input, uint8_t* key, uint8_t *output);
+void AES128_ECB_decrypt(uint8_t* input, uint8_t* key, uint8_t *output);
+
+#ifdef __cplusplus
+}
+#endif /* __cplusplus */
+#endif //_AES_H_
--
1.9.1
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