AES crypto driver

Makefile

@@ -6,7 +6,7 @@ TARGET = images/OpenModem
 OPT = s
 FORMAT = ihex
 
-SRC = main.c hardware/Serial.c hardware/AFSK.c hardware/VREF.c hardware/LED.c hardware/UserIO.c hardware/SD.c hardware/sdcard/diskio.c hardware/sdcard/ff.c hardware/sdcard/ffsystem.c hardware/sdcard/ffunicode.c hardware/Bluetooth.c hardware/GPS.c util/CRC-CCIT.c protocol/AX25.c protocol/KISS.c
+SRC = main.c hardware/Serial.c hardware/AFSK.c hardware/VREF.c hardware/LED.c hardware/UserIO.c hardware/SD.c hardware/sdcard/diskio.c hardware/sdcard/ff.c hardware/sdcard/ffsystem.c hardware/sdcard/ffunicode.c hardware/Bluetooth.c hardware/GPS.c hardware/Crypto.c hardware/crypto/AES.c util/CRC-CCIT.c protocol/AX25.c protocol/KISS.c
 
 
 # List Assembler source files here.
@@ -30,8 +30,6 @@ $(patsubst %,-I%,$(EXTRAINCDIRS))
 
 CFLAGS += -std=gnu99
 
-
-
 # Optional assembler flags.
 ASFLAGS = -Wa,-adhlns=$(<:.S=.lst),-gstabs 
 

hardware/Crypto.c

@@ -0,0 +1,66 @@
+#include "Crypto.h"
+
+uint8_t active_key[16];
+uint8_t active_iv[16];
+
+aes_128_context_t context;
+uint8_t current_vector[16];
+
+void crypto_init(void) {
+	crypto_test();
+	return;
+}
+
+void crypto_prepare(uint8_t key[16], uint8_t initialization_vector[16]) {
+  // Initialise the context with the key
+  aes_128_init(&context, key);
+
+  // Copy the IV into the current vector array
+  memcpy(current_vector, initialization_vector, 16);
+}
+
+void crypto_encrypt_block(uint8_t block[16]) {
+  int i;
+
+  // XOR the current vector with the block before encrypting
+  for (i = 0; i < 16; i++) {
+    block[i] ^= current_vector[i];
+  }
+
+  // Encrypt the block
+  aes_128_encrypt(&context, block);
+
+  // Copy the cipher output to the current vector
+  memcpy(current_vector, block, 16);
+}
+
+void crypto_decrypt_block(uint8_t block[16]) {
+  uint8_t temp_vector[16];
+  int i;
+
+  // Copy the cipher output to the temporary vector
+  memcpy(temp_vector, block, 16);
+
+  // Decrypt the block
+  aes_128_decrypt(&context, block);
+
+  // XOR the output with the current vector to fully decrypt
+  for (i = 0; i < 16; i++) {
+    block[i] ^= current_vector[i];
+  }
+
+  // Copy the temporary vector to the current vector
+  memcpy(current_vector, temp_vector, 16);
+}
+
+void load_key(void) {
+	// TODO: implement
+}
+
+void generate_iv(void) {
+	// TODO: implement
+}
+
+void crypto_test(void) {
+	
+}

hardware/Crypto.h

@@ -0,0 +1,14 @@
+#ifndef CRYPTO_H
+#define CRYPTO_H
+
+#include <string.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include "crypto/aes.h"
+
+void crypto_init(void);
+void crypto_test(void);
+
+#endif
+

hardware/crypto/AES.c

@@ -0,0 +1,361 @@
+/*
+MIT License
+
+Copyright (c) 2016 Andrew Carter
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+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 OR COPYRIGHT HOLDERS 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.
+
+Modifications copyright 2019 Mark Qvist
+
+*/
+
+#pragma GCC diagnostic push 
+#pragma GCC diagnostic ignored "-Wparentheses"
+
+#include <stdint.h>
+#include <string.h>
+#include <avr/pgmspace.h>
+
+#include "AES.h"
+
+// Preprocessor Definitions
+#define MAP(i,j) (((j) << 2) + (i))
+#define MUL(x,y) aes_GaloisFieldMultiply((x),(y))
+#define MUL2(x)  (((x) << 1) ^ (0x1B & (((x) >> 7) * 0xFF))) & 0xFF
+#define MUL3(x)  ((x) ^ MUL2(x))
+#define SUB4(x)  (((uint32_t)pgm_read_byte(&(s_box[((x) & 0xFF000000) >> 24])) << 24) | ((uint32_t)pgm_read_byte(&(s_box[((x) & 0xFF0000) >> 16])) << 16) | (pgm_read_byte(&(s_box[((x) & 0xFF00) >> 8])) << 8) | pgm_read_byte(&(s_box[((x) & 0xFF)])))
+
+// AES Tables
+const uint8_t s_box[256] PROGMEM = {
+  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
+};
+
+const uint8_t s_box_inverse[256] PROGMEM = {
+  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
+};
+
+const uint8_t rcon[10] = { 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1B, 0x36 };
+
+// AES Operation Definitions
+
+void aes_Rotate        (uint8_t block[4]);
+void aes_SubBytes      (uint8_t state[16]);
+void aes_InvSubBytes   (uint8_t state[16]);
+void aes_ShiftRows     (uint8_t state[16]);
+void aes_InvShiftRows  (uint8_t state[16]);
+void aes_MixColumns    (uint8_t state[16]);
+void aes_InvMixColumns (uint8_t state[16]);
+void aes_AddRoundKey   (uint8_t state[16], uint8_t sub_key[16]);
+
+// Maths Operation Definitions
+
+uint8_t aes_GaloisFieldMultiply (uint8_t fixed, uint8_t variable);
+
+// AES Core Procedures
+
+void aes_init(uint32_t *round_key, counter b, uint32_t *key, counter n)
+{
+  uint32_t t;
+  counter i, position, cycle;
+
+  memcpy(round_key, key, n * sizeof(uint32_t));
+
+  for (position = n, cycle = n, t = round_key[n - 1], i = 0; position < b; position++, cycle++) {
+    if (cycle == n) {
+      cycle = 0;
+
+      aes_Rotate((uint8_t *) &t);
+      t = SUB4(t);
+      ((uint8_t *) &t)[0] ^= rcon[i++];
+    } else if (cycle == 4 && n == 8) {
+      t = SUB4(t);
+    }
+
+    t ^= round_key[position - n];
+    round_key[position] = t;
+  }
+}
+
+void aes_encrypt(uint8_t *round_key, uint8_t block[16], counter rounds)
+{
+  counter i;
+
+  aes_AddRoundKey(block, round_key);
+
+  for (i = 1; i < rounds; i++) {
+    aes_SubBytes(block);
+    aes_ShiftRows(block);
+    aes_MixColumns(block);
+    aes_AddRoundKey(block, round_key + (i << 4));
+  }
+
+  aes_SubBytes(block);
+  aes_ShiftRows(block);
+  aes_AddRoundKey(block, round_key + (i << 4));
+}
+
+void aes_decrypt(uint8_t *round_key, uint8_t block[16], counter rounds)
+{
+  counter i;
+
+  aes_AddRoundKey(block, round_key + (rounds << 4));
+
+  for (i = 1; i < rounds; i++) {
+    aes_InvShiftRows(block);
+    aes_InvSubBytes(block);
+    aes_AddRoundKey(block, round_key + ((rounds - i) << 4));
+    aes_InvMixColumns(block);
+  }
+
+  aes_InvShiftRows(block);
+  aes_InvSubBytes(block);
+  aes_AddRoundKey(block, round_key);
+}
+
+// AES Key Specific API
+
+void aes_256_init(aes_256_context_t *context, uint8_t key[32])
+{
+  aes_init((uint32_t *) context->round_key, sizeof(context->round_key) / sizeof(uint32_t), (uint32_t *) key, 8);
+}
+
+void aes_256_encrypt(aes_256_context_t *context, uint8_t block[16])
+{
+  aes_encrypt(context->round_key, block, AES_256_ROUNDS);
+}
+
+void aes_256_decrypt(aes_256_context_t *context, uint8_t block[16])
+{
+  aes_decrypt(context->round_key, block, AES_256_ROUNDS);
+}
+
+void aes_192_init(aes_192_context_t *context, uint8_t key[24])
+{
+  aes_init((uint32_t *) context->round_key, sizeof(context->round_key) / sizeof(uint32_t), (uint32_t *) key, 6);
+}
+
+void aes_192_encrypt(aes_192_context_t *context, uint8_t block[16])
+{
+  aes_encrypt(context->round_key, block, AES_192_ROUNDS);
+}
+
+void aes_192_decrypt(aes_192_context_t *context, uint8_t block[16])
+{
+  aes_decrypt(context->round_key, block, AES_192_ROUNDS);
+}
+
+void aes_128_init(aes_128_context_t *context, uint8_t key[16])
+{
+  aes_init((uint32_t *) context->round_key, sizeof(context->round_key) / sizeof(uint32_t), (uint32_t *) key, 4);
+}
+
+void aes_128_encrypt(aes_128_context_t *context, uint8_t block[16])
+{
+  aes_encrypt(context->round_key, block, AES_128_ROUNDS);
+}
+
+void aes_128_decrypt(aes_128_context_t *context, uint8_t block[16])
+{
+  aes_decrypt(context->round_key, block, AES_128_ROUNDS);
+}
+
+// AES Operation Implementations
+
+void aes_Rotate(uint8_t block[4])
+{
+  uint8_t tmp;
+
+  tmp = block[0];
+  block[0] = block[1];
+  block[1] = block[2];
+  block[2] = block[3];
+  block[3] = tmp;
+}
+
+void aes_SubBytes(uint8_t state[16])
+{
+  counter i = 16;
+
+  while (i--) {
+    state[i] = pgm_read_byte(&(s_box[state[i]]));
+  }
+}
+
+void aes_InvSubBytes(uint8_t state[16])
+{
+  counter i = 16;
+
+  while (i--) {
+    state[i] = pgm_read_byte(&(s_box_inverse[state[i]]));
+  }
+}
+
+void aes_ShiftRows(uint8_t state[16])
+{
+  uint8_t tmp;
+
+  tmp = state[MAP(1,0)];
+  state[MAP(1,0)] = state[MAP(1,1)];
+  state[MAP(1,1)] = state[MAP(1,2)];
+  state[MAP(1,2)] = state[MAP(1,3)];
+  state[MAP(1,3)] = tmp;
+
+  tmp = state[MAP(2,0)];
+  state[MAP(2,0)] = state[MAP(2,2)];
+  state[MAP(2,2)] = tmp;
+
+  tmp = state[MAP(2,1)];
+  state[MAP(2,1)] = state[MAP(2,3)];
+  state[MAP(2,3)] = tmp;
+
+  tmp = state[MAP(3,0)];
+  state[MAP(3,0)] = state[MAP(3,3)];
+  state[MAP(3,3)] = state[MAP(3,2)];
+  state[MAP(3,2)] = state[MAP(3,1)];
+  state[MAP(3,1)] = tmp;
+}
+
+void aes_InvShiftRows(uint8_t state[16])
+{
+  uint8_t tmp;
+
+  tmp = state[MAP(3,0)];
+  state[MAP(3,0)] = state[MAP(3,1)];
+  state[MAP(3,1)] = state[MAP(3,2)];
+  state[MAP(3,2)] = state[MAP(3,3)];
+  state[MAP(3,3)] = tmp;
+
+  tmp = state[MAP(2,0)];
+  state[MAP(2,0)] = state[MAP(2,2)];
+  state[MAP(2,2)] = tmp;
+
+  tmp = state[MAP(2,1)];
+  state[MAP(2,1)] = state[MAP(2,3)];
+  state[MAP(2,3)] = tmp;
+
+  tmp = state[MAP(1,0)];
+  state[MAP(1,0)] = state[MAP(1,3)];
+  state[MAP(1,3)] = state[MAP(1,2)];
+  state[MAP(1,2)] = state[MAP(1,1)];
+  state[MAP(1,1)] = tmp;
+}
+
+void aes_MixColumns(uint8_t state[16])
+{
+  counter i = 4;
+  uint8_t new_state[4];
+
+  while (i--) {
+    new_state[0] = MUL2(state[MAP(0,i)]) ^ MUL3(state[MAP(1,i)]) ^      state[MAP(2,i)]  ^      state[MAP(3,i)] ;
+    new_state[1] =      state[MAP(0,i)]  ^ MUL2(state[MAP(1,i)]) ^ MUL3(state[MAP(2,i)]) ^      state[MAP(3,i)] ;
+    new_state[2] =      state[MAP(0,i)]  ^      state[MAP(1,i)]  ^ MUL2(state[MAP(2,i)]) ^ MUL3(state[MAP(3,i)]);
+    new_state[3] = MUL3(state[MAP(0,i)]) ^      state[MAP(1,i)]  ^      state[MAP(2,i)]  ^ MUL2(state[MAP(3,i)]);
+
+    state[MAP(0,i)] = new_state[0];
+    state[MAP(1,i)] = new_state[1];
+    state[MAP(2,i)] = new_state[2];
+    state[MAP(3,i)] = new_state[3];
+  }
+}
+
+void aes_InvMixColumns(uint8_t state[16])
+{
+  counter i = 4;
+  uint8_t new_state[4];
+
+  while (i--) {
+    new_state[0] = MUL(14, state[MAP(0,i)]) ^ MUL(11, state[MAP(1,i)]) ^ MUL(13, state[MAP(2,i)]) ^ MUL( 9, state[MAP(3,i)]);
+    new_state[1] = MUL( 9, state[MAP(0,i)]) ^ MUL(14, state[MAP(1,i)]) ^ MUL(11, state[MAP(2,i)]) ^ MUL(13, state[MAP(3,i)]);
+    new_state[2] = MUL(13, state[MAP(0,i)]) ^ MUL( 9, state[MAP(1,i)]) ^ MUL(14, state[MAP(2,i)]) ^ MUL(11, state[MAP(3,i)]);
+    new_state[3] = MUL(11, state[MAP(0,i)]) ^ MUL(13, state[MAP(1,i)]) ^ MUL( 9, state[MAP(2,i)]) ^ MUL(14, state[MAP(3,i)]);
+
+    state[MAP(0,i)] = new_state[0];
+    state[MAP(1,i)] = new_state[1];
+    state[MAP(2,i)] = new_state[2];
+    state[MAP(3,i)] = new_state[3];
+  }
+}
+
+void aes_AddRoundKey(uint8_t state[16], uint8_t sub_key[16])
+{
+#ifdef OPTIMISE_8_BIT
+
+  counter i = 16;
+
+  while (i--) {
+    state[i] ^= sub_key[i];
+  }
+
+#else
+
+  counter i = 4;
+
+  while (i--) {
+    ((uint32_t *) state)[i] ^= ((uint32_t *) sub_key)[i];
+  }
+
+#endif
+}
+
+// Maths Operation Implementations
+
+uint8_t aes_GaloisFieldMultiply(uint8_t fixed, uint8_t variable)
+{
+  uint8_t result = 0;
+
+  while (fixed) {
+    result ^= variable & ((fixed & 0x01) * 0xFF);
+    variable = MUL2(variable);
+    fixed >>= 1;
+  }
+
+  return result;
+}
+
+#pragma GCC diagnostic pop

hardware/crypto/AES.h

@@ -0,0 +1,74 @@
+/*
+MIT License
+
+Copyright (c) 2016 Andrew Carter
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+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 OR COPYRIGHT HOLDERS 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.
+*/
+
+#ifndef AES_H
+#define AES_H
+
+#include <stdint.h>
+
+#define AES_256_ROUNDS 14
+#define AES_192_ROUNDS 12
+#define AES_128_ROUNDS 10
+
+// Uncomment this (or compile with -DOPT_8_BIT) to optimise for an 8 bit architecture
+#define AES_OPT_8_BIT
+
+#ifdef AES_OPT_8_BIT
+  typedef uint8_t counter;
+#else
+  typedef unsigned int counter;
+#endif
+
+// AES-256
+
+typedef struct aes_256_context_t_ {
+  uint8_t round_key[(AES_256_ROUNDS + 1) * 16];
+} aes_256_context_t;
+
+void aes_256_init    (aes_256_context_t *context, uint8_t key[32]);
+void aes_256_encrypt (aes_256_context_t *context, uint8_t block[16]);
+void aes_256_decrypt (aes_256_context_t *context, uint8_t block[16]);
+
+// AES-192
+
+typedef struct aes_192_context_t_ {
+  uint8_t round_key[(AES_192_ROUNDS + 1) * 16];
+} aes_192_context_t;
+
+void aes_192_init    (aes_192_context_t *context, uint8_t key[24]);
+void aes_192_encrypt (aes_192_context_t *context, uint8_t block[16]);
+void aes_192_decrypt (aes_192_context_t *context, uint8_t block[16]);
+
+// AES-128
+
+typedef struct aes_128_context_t_ {
+  uint8_t round_key[(AES_128_ROUNDS + 1) * 16];
+} aes_128_context_t;
+
+void aes_128_init    (aes_128_context_t *context, uint8_t key[16]);
+void aes_128_encrypt (aes_128_context_t *context, uint8_t block[16]);
+void aes_128_decrypt (aes_128_context_t *context, uint8_t block[16]);
+
+#endif
+

main.c

@@ -13,6 +13,7 @@
 #include "hardware/LED.h"
 #include "hardware/UserIO.h"
 #include "hardware/SD.h"
+#include "hardware/Crypto.h"
 #include "hardware/Bluetooth.h"
 #include "hardware/GPS.h"
 #include "protocol/AX25.h"
@@ -69,6 +70,7 @@ void init(void) {
     ax25_init(&AX25, &modem, &modem.fd, ax25_callback);
     kiss_init(&AX25, &modem, &serial);
     sd_init();
+    crypto_init();
     bluetooth_init();
     gps_init(&serial);
     usrio_init();