Skip to content

Instantly share code, notes, and snippets.

Embed
What would you like to do?
Arduino library for the ATSHA204 authentication chip
/*
* Arduino library for the ATSHA204 authentication chip.
*
* The ATSHA204 is a tiny and low-power authentication chip. This library
* implements a simple interface to access most of the chip functionality from
* an Arduino.
*
* Note that only the Single-Wire Interface (SWI) is currently supported.
*
* FEATURES:
* + Raw memory read
* + Config and Data memory lock
* + Random number generator
* + Nonce generation
* + Key derivation
*
* GETTING STARTED:
*
* #include <ATSHA204.h>
*
* #define ATSHA204_PIN 9
*
* ATSHA204 sha204(ATSHA204_PIN);
*
* int rc;
*
* void setup() {
* Serial.begin(9600);
*
* if (sha204.wake())
* while (1); // error
*
* //sha204.lock(0);
* }
*
* void loop() {
* int i;
* uint8_t buf[32];
*
* rc = sha204.wake();
* if (rc) Serial.println("wake(): error");
*
* // check if config memory is locked
* rc = sha204.read(0, 0x15, buf, 4);
* if (rc) Serial.println("read(): error");
*
* if (buf[3] == 0x55)
* Serial.println("Config is not locked");
*
* // generate and print random numbers
* Serial.print("Random numbers: ");
*
* rc = sha204.rand(1, buf);
* if (rc) Serial.println("rand(): error");
*
* for (i = 0; i < 32; i++)
* Serial.print(buf[i], HEX);
*
* Serial.println("");
*
* delay(5000);
* }
*
* TODO
* + Raw memory write
* + HMAC generation
* + Digest generation
* + ...
*
* Copyright (c) 2013, Alessandro Ghedini
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
* IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <Arduino.h>
#include "ATSHA204.h"
#include <avr/cpufunc.h>
#include <string.h>
enum ATSHA204_FLAGS {
FLAG_COMMAND = 0x77,
FLAG_TRANSMIT = 0x88,
FLAG_IDLE = 0xbb,
FLAG_SLEEP = 0xcc
};
enum ATSHA204_ZONES {
CONFIG,
DATA,
OTP
};
enum ATSHA204_OPCODES {
OP_DERIVE_KEY = 0x1C,
OP_DEV_REV = 0x30,
OP_GEN_DIG = 0x15,
OP_HMAC = 0x11,
OP_CHECK_MAC = 0x28,
OP_LOCK = 0x17,
OP_MAC = 0x18,
OP_NONCE = 0x16,
OP_PAUSE = 0x01,
OP_RANDOM = 0x1B,
OP_READ = 0x02,
OP_WRITE = 0x12
};
enum ATSHA204_ERRNO {
ERR_SUCCESS = 0x00,
ERR_MISCOMPARE = 0x01,
ERR_PARSE = 0x03,
ERR_EXECUTION = 0x0f,
ERR_WAKE = 0x11,
ERR_CRC = 0xff
};
#define DELAY_WLO (60 + 20) /* min 60 us */
#define DELAY_WHI (2.5 + 0.5) /* min 2.5 ms */
#define DELAY_BIT (4) /* ~230.4 kbps */
#define DELAY_RTX (15)
#define DELAY_SYN (85)
void crc16(uint8_t *buf, uint8_t len, uint8_t *crc) {
uint8_t i;
uint16_t crc16 = 0;
for (i = 0; i < len; i++) {
uint8_t shift;
for (shift = 0x01; shift > 0x00; shift <<= 1) {
uint8_t data_bit = (buf[i] & shift) ? 1 : 0;
uint8_t crc_bit = crc16 >> 15;
crc16 <<= 1;
if ((data_bit ^ crc_bit) != 0)
crc16 ^= 0x8005;
}
}
crc[0] = (uint8_t) (crc16 & 0x00FF);
crc[1] = (uint8_t) (crc16 >> 8);
}
ATSHA204::ATSHA204(int pin) {
pin_bit = digitalPinToBitMask(pin);
uint8_t port = digitalPinToPort(pin);
port_ddr = portModeRegister(port);
port_out = portOutputRegister(port);
port_in = portInputRegister(port);
}
void ATSHA204::setPin(uint8_t is_high) {
*port_ddr |= pin_bit;
if (is_high)
*port_out |= pin_bit;
else
*port_out &= ~pin_bit;
}
int ATSHA204::send(uint8_t *buf, uint8_t len) {
uint8_t i, bit_mask;
noInterrupts();
*port_out |= pin_bit;
*port_ddr |= pin_bit;
delayMicroseconds(DELAY_RTX);
for (i = 0; i < len; i++) {
for (bit_mask = 1; bit_mask > 0; bit_mask <<= 1) {
if (bit_mask & buf[i]) {
/* One token */
*port_out &= ~pin_bit;
delayMicroseconds(DELAY_BIT);
*port_out |= pin_bit;
delayMicroseconds(DELAY_BIT * 7);
} else {
/* Zero token */
*port_out &= ~pin_bit;
delayMicroseconds(DELAY_BIT);
*port_out |= pin_bit;
delayMicroseconds(DELAY_BIT);
*port_out &= ~pin_bit;
delayMicroseconds(DELAY_BIT);
*port_out |= pin_bit;
delayMicroseconds(DELAY_BIT * 5);
}
}
}
interrupts();
return 0;
}
int ATSHA204::recv(uint8_t *buf, uint8_t len) {
uint8_t status = 0;
uint8_t i;
uint8_t recv_flag = FLAG_TRANSMIT;
send(&recv_flag, 1);
noInterrupts();
*port_ddr &= ~pin_bit;
for (i = 0; i < len; i++) {
uint8_t bit_mask;
for (bit_mask = 1; bit_mask > 0; bit_mask <<= 1) {
uint8_t pulse_count = 0;
uint8_t timeout_count = 255;
/* Start pulse */
while (--timeout_count > 0) {
if ((*port_in & pin_bit) == 0) /* falling */
break;
}
if (timeout_count == 0) {
status = -1;
break;
}
do {
if ((*port_in & pin_bit) != 0) { /* rising */
pulse_count = 1;
break;
}
} while (--timeout_count > 0);
if (pulse_count == 0) {
status = -1;
break;
}
timeout_count = 26;
do {
if ((*port_in & pin_bit) == 0) {
pulse_count = 2;
break;
}
} while (--timeout_count > 0);
if (pulse_count == 2) {
do {
if ((*port_in & pin_bit) != 0)
break;
} while (timeout_count-- > 0);
} else
buf[i] |= bit_mask; /* one token */
}
if (status != 0)
break;
}
interrupts();
return status;
}
int ATSHA204::wake() {
uint8_t wake_resp[4];
wake_resp[0] = 0;
wake_resp[1] = 0;
wake_resp[2] = 0;
wake_resp[3] = 0;
setPin(0);
delayMicroseconds(DELAY_WLO);
setPin(1);
delay(DELAY_WHI);
recv(wake_resp, 4);
if ((wake_resp[0] == 4) && (wake_resp[1] == ERR_WAKE))
return 0;
else
return -1;
}
int ATSHA204::sleep() {
uint8_t flag = FLAG_SLEEP;
return send(&flag, 1);
}
int ATSHA204::sync(uint8_t *buf, uint8_t len) {
int rc;
uint8_t sleep = FLAG_SLEEP;
delay(DELAY_SYN);
rc = recv(buf, len);
if (!rc) return rc;
this -> sleep();
return wake();
}
int ATSHA204::exec(uint8_t *tx, uint8_t tx_len,
uint8_t *rx, uint8_t rx_len,
uint8_t exec_delay, uint8_t max_delay) {
uint8_t rx_crc[2];
uint8_t cmd_flag = FLAG_COMMAND;
crc16(tx, tx_len - 2, tx + (tx_len - 2));
send(&cmd_flag, 1);
send(tx, tx_len);
delay(exec_delay);
/* FIXME: use max_delay */
do {
recv(rx, rx_len);
} while (rx[0] == 0);
if (rx[0] != rx_len)
return -1;
crc16(rx, (rx_len - 2), rx_crc);
if ((rx_crc[0] == rx[rx_len - 2]) && (rx_crc[1] == rx[rx_len - 1]))
return 0;
/* crc check failed */
return -1;
}
int ATSHA204::serial(uint8_t *buf) {
int rc, i = 0;
uint8_t tmp[4];
/* memory barrier to avoid buf writes re-ordering */
__asm__ __volatile__("":::"memory");
rc = read(0, 0, buf, 4);
if (rc) return rc;
i += 4;
rc = read(0, 0x02, buf + i, 4);
if (rc) return rc;
i += 4;
rc = read(0, 0x03, tmp, 4);
if (rc) return rc;
buf[i] = tmp[0];
return 0;
}
int ATSHA204::devRev(uint8_t *buf) {
int rc;
uint8_t cmd[7];
uint8_t resp[7];
memset(resp, 0x00, 7);
cmd[0] = 7;
cmd[1] = OP_DEV_REV;
cmd[2] = 0;
cmd[3] = 0;
cmd[4] = 0;
rc = exec(cmd, cmd[0], resp, 7, 1, 2);
memcpy(buf, resp + 1, 4);
return rc;
}
int ATSHA204::read(uint8_t zone, uint16_t addr, uint8_t *buf, uint8_t len) {
int rc;
uint8_t cmd[7];
uint8_t resp[len + 3];
memset(resp, 0x00, len + 3);
if (len == 32)
zone |= (1 << 8);
cmd[0] = 7;
cmd[1] = OP_READ;
cmd[2] = zone;
cmd[3] = addr;
cmd[4] = 0;
rc = exec(cmd, cmd[0], resp, len + 3, 1, 4);
memcpy(buf, resp + 1, len);
return rc;
}
int ATSHA204::write(uint8_t zone, uint8_t addr,
uint8_t *buf, uint8_t len, uint8_t *mac) {
int rc;
uint8_t cmd[72];
uint8_t resp[4];
memset(resp, 0x00, 4);
uint8_t data_size = len;
if ((len != 4) || (len != 32))
return -1;
if (len == 32)
zone |= (1 << 8);
if (mac)
data_size += 32;
cmd[0] = 7 + data_size;
cmd[1] = OP_READ;
cmd[2] = zone;
cmd[3] = addr;
cmd[4] = 0;
memcpy(cmd + 5, buf, len);
if (mac)
memcpy(cmd + 5 + len, mac, 32);
rc = exec(cmd, cmd[0], resp, 4, 4, 42);
if (cmd[1] != ERR_SUCCES)
return cmd[1];
return rc;
}
int ATSHA204::lock(uint8_t zone) {
uint8_t cmd[7];
uint8_t resp[7];
memset(resp, 0x00, 7);
/* FIXME: check CRC */
zone |= (1 << 8);
cmd[0] = 7;
cmd[1] = OP_LOCK;
cmd[2] = zone;
cmd[3] = 0;
cmd[4] = 0;
return exec(cmd, cmd[0], resp, 7, 5, 24);
}
int ATSHA204::rand(uint8_t update, uint8_t *buf) {
int rc;
uint8_t cmd[7];
uint8_t resp[35];
memset(resp, 0x00, 35);
cmd[0] = 7;
cmd[1] = OP_RANDOM;
cmd[2] = !update;
cmd[3] = 0;
cmd[4] = 0;
rc = exec(cmd, cmd[0], resp, 35, 11, 50);
memcpy(buf, resp + 1, 32);
return rc;
}
int ATSHA204::nonce(uint8_t mode, uint8_t *in, uint8_t *out) {
int rc;
uint8_t cmd[39];
uint8_t resp[35];
uint8_t data_size = 0;
uint8_t resp_size = 0;
switch (mode) {
case 0:
case 1:
data_size = 20;
resp_size = 35;
break;
case 3:
data_size = 32;
resp_size = 4;
break;
default:
return -1;
}
memset(resp, 0x00, resp_size);
cmd[0] = 7 + data_size;
cmd[1] = OP_NONCE;
cmd[2] = mode;
cmd[3] = 0;
cmd[4] = 0;
memcpy(cmd + 5, in, data_size);
rc = exec(cmd, cmd[0], resp, resp_size, 11, 50);
memcpy(out, resp + 1, resp_size - 3);
return rc;
}
int ATSHA204::deriveKey(uint8_t random, uint8_t target, uint8_t *mac) {
int rc;
uint8_t cmd[39];
uint8_t data_size = 0;
uint8_t resp[4];
memset(resp, 0x00, 4);
cmd[0] = 7 + data_size;
cmd[1] = OP_DERIVE_KEY;
cmd[2] = random;
cmd[3] = 0;
cmd[4] = 0;
rc = exec(cmd, cmd[0], resp, 4, 14, 62);
if (resp[1])
return resp[1];
return rc;
}
/*
* Arduino library for the ATSHA204 authentication chip.
*
* Copyright (c) 2013, Alessandro Ghedini
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
* IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef ATSHA204_H
#define ATSHA204_H
class ATSHA204 {
public:
ATSHA204(int pin);
int sleep();
int wake();
int sync(uint8_t *buf, uint8_t len);
int serial(uint8_t *buf);
int devRev(uint8_t *buf);
int read(uint8_t zone, uint16_t addr,
uint8_t *buf, uint8_t len);
int write(uint8_t zone, uint8_t addr,
uint8_t *buf, uint8_t len, uint8_t *mac);
int lock(uint8_t zone);
int rand(uint8_t update, uint8_t *buf);
int nonce(uint8_t mode, uint8_t *in, uint8_t *out);
int deriveKey(uint8_t random, uint8_t target, uint8_t *macW);
private:
int pin;
uint8_t pin_bit;
volatile uint8_t *port_ddr, *port_out, *port_in;
void setPin(uint8_t is_high);
int send(uint8_t *buf, uint8_t len);
int recv(uint8_t *buf, uint8_t len);
int exec(uint8_t *tx, uint8_t tx_len,
uint8_t *rx, uint8_t rx_len,
uint8_t exec_delay, uint8_t max_delay);
};
#endif
@Manuele88

This comment has been minimized.

Copy link

commented Apr 13, 2015

Hi,

Just a question. Can you tell me how I can write in the EEPROM, in particular what is mac??
I m testing the istruction: rc = sha204.write(2,0x41,buf,4,mac);
but i don t have any result of written....

Thanks

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
You can’t perform that action at this time.