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/*
* spreadspace avr utils
*
*
* Copyright (C) 2013-2016 Christian Pointner <equinox@spreadspace.org>
*
* This file is part of spreadspace avr utils.
*
* spreadspace avr utils is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* any later version.
*
* spreadspace avr utils is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with spreadspace avr utils. If not, see <http://www.gnu.org/licenses/>.
*/
#include <avr/io.h>
#include <avr/wdt.h>
#include <avr/interrupt.h>
#include <avr/power.h>
#include <stdio.h>
#include <string.h>
#include "util.h"
#include "led.h"
#include "usbio.h"
#include <Crypto.h>
#include <ChaChaPoly.h>
ChaChaPoly cipher;
void print_hex_dump(const uint8_t* data, size_t len) {
for(size_t i=0; i<len; ++i) {
printf(" 0x%02X", data[i]);
if((i+1)%8 == 0) printf("\r\n");
}
printf("\r\n");
}
void run_crypto()
{
printf("running encrypt/decrypt test using ChaCha20Poly1305:\r\n");
printf("\r\nencrypting...\r\n");
uint8_t hdr[] = "hello world!";
size_t hdr_len = sizeof(hdr)-1;
uint8_t body[] = "this is a secret message.";
size_t body_len = sizeof(body)-1;
uint8_t key[] = {0x70, 0x43, 0xb6, 0x9b, 0xde, 0x20, 0x44, 0x66,
0x61, 0xba, 0x57, 0x9e, 0x83, 0xfd, 0xa0, 0x83,
0x0e, 0x3e, 0x61, 0xc9, 0x5b, 0x5a, 0xc8, 0xde,
0xeb, 0x79, 0x97, 0x3b, 0xa0, 0xdf, 0x02, 0xd8};
uint8_t iv[] = {0x6f, 0xac, 0x1c, 0x6a, 0x94, 0xa5, 0x78, 0x87,
0x61, 0xcf, 0x9e, 0xcd};
uint8_t buf[256];
uint8_t tag[16];
memset(buf, 0, sizeof(buf));
memset(tag, 0, sizeof(tag));
led_on();
cipher.clear();
if(!cipher.setKey(key, sizeof(key))) {
printf("failed to set key\r\n");
return;
}
if(!cipher.setIV(iv, sizeof(iv))) {
printf("failed to set iv\r\n");
return;
}
led_off();
led_on();
cipher.addAuthData(hdr, hdr_len);
cipher.encrypt(buf, body, body_len);
cipher.computeTag(tag, sizeof(tag));
led_off();
printf("encrypted data (%d bytes):\r\n", body_len);
print_hex_dump(buf, body_len);
printf("\r\n");
printf("auth tag (%d bytes):\r\n", sizeof(tag));
print_hex_dump(tag, sizeof(tag));
printf("\r\ndecrypting...\r\n");
memcpy(body, buf, body_len);
memset(buf, 0, sizeof(buf));
led_on();
cipher.clear();
if(!cipher.setKey(key, sizeof(key))) {
printf("failed to set key\r\n");
return;
}
if(!cipher.setIV(iv, sizeof(iv))) {
printf("failed to set iv\r\n");
return;
}
led_off();
led_on();
cipher.addAuthData(hdr, hdr_len);
cipher.decrypt(buf, body, body_len);
bool ct = cipher.checkTag(tag, sizeof(tag));
led_off();
if(!ct) {
printf("auth tag mismatch!\r\n");
return;
} else {
printf("auth tag correct!\r\n");
}
printf("decrypted body: '%s'\r\n", buf);
}
void handle_cmd(uint8_t cmd)
{
switch(cmd) {
case 'c': run_crypto(); break;
case 'r': reset2bootloader(); break;
default: printf("unknown command"); break;
}
printf("\r\n");
}
int main(void)
{
MCUSR &= ~(1 << WDRF);
wdt_disable();
cpu_init();
led_init();
usbio_init();
sei();
for(;;) {
int16_t BytesReceived = usbio_bytes_received();
while(BytesReceived > 0) {
int ReceivedByte = fgetc(stdin);
if(ReceivedByte != EOF) {
handle_cmd(ReceivedByte);
}
BytesReceived--;
}
usbio_task();
}
}
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