Micro Coder

Library to generate ES256 based JWT for microcontroller (Arduino, ESP etc.)

Requirements

• This library works on Arduino framework
• You need to install micro-ecc library

Installation

This library is not yet available to install via package manager. You can download and unpack it manually, or use git submodule.

Usage

This library exposes three functions:

• ucoderSetDefaultRNG(), this will configure RNG for uECC library
• ucoderCalculateSize(char *payload), calculate JWT size
• ucoderCreate(const char *privateKey, char *payload, char *jwt), to create JSON Web Token
  • privateKey format must be a ":" separated hex bytes char array (see example below)
  • payload can be any char array size
  • jwt is an output container for this function, its size must be determied via ucoderCalculateSize(payload),

Example:

// Arduino.h is auto included in Arduino IDE
#include <Arduino.h>
#include "modules/micro-coder/ucoder.h"

const char privateKey[] = "6f:fa:ac:f3:16:88:89:2b:62:43:e3:52:7c:17:03:19:32:b5:00:31:47:cc:49:0c:63:ca:8b:a2:d9:1d:6c:eb";

void setup() {
  Serial.begin(9600);
  ucoderSetDefaultRNG();
}

void loop() {
  char payload[] = "{\"aud\":\"1234567890\"}";
  char jwt[ucoderCalculateSize(payload)];
  ucoderCreate(privateKey, payload, jwt);
  Serial.println(jwt);
  delay(10000);
}