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Implemented AES-128 encryption

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This commit is contained in:
Mark Qvist 2019-02-07 18:36:40 +01:00
parent 0e24b54657
commit b3b1a9b253
15 changed files with 730 additions and 118 deletions
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84
hardware/Crypto.c
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@ -25,23 +25,26 @@ void crypto_init(void) {
}
if (encryption_enabled) {
// TODO: Set flags for crypto enabled
// TODO: Remove
// for (uint8_t i = 0; i < 130; i++) {
// crypto_test();
// }
LED_indicate_enabled_crypto();
} else {
LED_indicate_error_crypto();
}
}
void crypto_prepare(uint8_t key[CRYPTO_KEY_SIZE], uint8_t initialization_vector[CRYPTO_KEY_SIZE]) {
void crypto_generate_hmac(uint8_t *data, size_t length) {
hmac_md5(crypto_work_block, active_key, CRYPTO_KEY_SIZE_BITS, data, length*8);
}
bool crypto_enabled(void) {
return encryption_enabled;
}
void crypto_prepare(void) {
// Initialise the context with the key
aes_128_init(&context, key);
aes_128_init(&context, active_key);
// Copy the IV into the current vector array
memcpy(current_vector, initialization_vector, CRYPTO_KEY_SIZE);
memcpy(current_vector, active_iv, CRYPTO_KEY_SIZE);
}
void crypto_encrypt_block(uint8_t block[CRYPTO_KEY_SIZE]) {
@ -82,7 +85,6 @@ bool load_entropy_index(void) {
if (sd_mounted()) {
crypto_fr = f_open(&crypto_fp, PATH_ENTROPY_INDEX, FA_READ);
if (crypto_fr == FR_NO_FILE) {
//printf("Entropy index file does not exist\r\n");
f_close(&crypto_fp);
crypto_fr = f_open(&crypto_fp, PATH_ENTROPY_INDEX, FA_CREATE_NEW | FA_WRITE);
@ -99,27 +101,20 @@ bool load_entropy_index(void) {
} else {
//printf("Could not write index to index file\r\n");
}
} else {
//printf("Could not create index file\r\n");
}
crypto_fr = f_open(&crypto_fp, PATH_ENTROPY_INDEX, FA_READ);
}
if (crypto_fr == FR_OK) {
//printf("Opened entropy index file\r\n");
UINT read = 0;
crypto_fr = f_read(&crypto_fp, crypto_fb, sizeof(entropy_index), &read);
f_close(&crypto_fp);
if (crypto_fr == FR_OK && read == sizeof(entropy_index)) {
memcpy(&entropy_index, crypto_fb, sizeof(entropy_index));
//printf("Entropy index is now: %lX\r\n", entropy_index);
return true;
}
} else {
//printf("Error opening entropy index file\r\n");
}
}
f_close(&crypto_fp);
@ -148,15 +143,8 @@ bool load_entropy(void) {
crypto_fr = f_open(&crypto_fp, PATH_ENTROPY_SOURCE, FA_READ);
if (crypto_fr == FR_OK) {
uint32_t fsize = f_size(&crypto_fp);
//uint32_t fpoint = crypto_fp.fptr;
//printf("Opened entropy file\r\n\tSize is %lu\r\n\tPointer is at %lX \r\n\tSeeking to index: %lX\r\n", fsize, fpoint, entropy_index);
crypto_fr = f_lseek(&crypto_fp, entropy_index);
//fpoint = crypto_fp.fptr;
//printf("After seek, pointer is now at %lX\r\n", fpoint);
if (crypto_fr == FR_OK && crypto_fp.fptr < fsize-sizeof(entropy)) {
UINT read = 0;
crypto_fr = f_read(&crypto_fp, crypto_fb, sizeof(entropy), &read);
@ -164,18 +152,14 @@ bool load_entropy(void) {
if (crypto_fr == FR_OK) {
memcpy(&entropy, crypto_fb, sizeof(entropy));
//printf("Read entropy from SD: %lX\r\n", entropy);
srandom(entropy);
entropy_loaded = true;
ivs_generated = 0;
return true;
} else {
//printf("Could not read entropy data from SD\r\n");
}
} else {
f_close(&crypto_fp);
//printf("Could not seek in index file, entropy exhausted\r\n");
LED_indicate_error_crypto();
}
}
@ -190,46 +174,30 @@ bool load_key(void) {
if (sd_mounted()) {
crypto_fr = f_open(&crypto_fp, PATH_AES_128_KEY, FA_READ);
if (crypto_fr == FR_OK) {
//printf("File open\r\n");
UINT read = 0;
crypto_fr = f_read(&crypto_fp, crypto_fb, CRYPTO_KEY_SIZE, &read);
f_close(&crypto_fp);
if (crypto_fr == FR_OK && read == CRYPTO_KEY_SIZE) {
//printf("Loaded AES-128 Key: ");
for (uint8_t i = 0; i < 16; i++) {
active_key[i] = crypto_fb[i];
//printf("%X ", crypto_fb[i]);
}
//printf("\r\n");
return true;
} else {
//printf("Error %d reading file, read %d bytes.\r\n", crypto_fr, read);
}
} else {
//printf("Could not open file\r\n");
}
} else {
//printf("SD not mounted\r\n");
}
return false;
}
bool generate_iv(void) {
bool crypto_generate_iv(void) {
if (entropy_loaded) {
for (uint8_t i = 0; i < 16; i++) {
active_iv[i] = (uint8_t)random();
}
ivs_generated++;
// TODO: remove
/*printf("Generated IV: ");
for (uint8_t i = 0; i < 16; i++) {
printf("%X ", active_iv[i]);
}
printf("\r\n");*/
if (ivs_generated >= MAX_IVS_PER_ENTROPY_BLOCK) {
load_entropy();
}
@ -240,24 +208,12 @@ bool generate_iv(void) {
}
}
// TODO: Remove this
void crypto_test(void) {
generate_iv();
uint8_t work_block[16];
memset(work_block, 0x70, 16);
work_block[15] = 0x00;
//printf("Work block plaintext: ===%s===\r\n", work_block);
crypto_prepare(active_key, active_iv);
crypto_encrypt_block(work_block);
//printf("Work block ciphertext: ===%s===\r\n", work_block);
crypto_prepare(active_key, active_iv);
crypto_decrypt_block(work_block);
printf("Work block plaintext: ===%s===\r\n", work_block);
uint8_t *crypto_get_iv(void) {
return active_iv;
}
void crypto_set_iv_from_workblock(void) {
memcpy(active_iv, crypto_work_block, CRYPTO_KEY_SIZE);
}
// TODO: test entropy exhaustion