@jnode/auth

Simple authorization package for Node.js.

Installation

npm i @jnode/auth

Quick start

Import

const { AuthService } = require('@jnode/auth');
const crypto = require('crypto');

Basic usage

// Generate a pair of keys for demonstration
const { publicKey, privateKey } = crypto.generateKeyPairSync('rsa', {
  modulusLength: 2048,
});

// Initialize the service
const auth = new AuthService(publicKey, privateKey);

// Sign a token
const token = auth.signToken({ alg: 'RSA-SHA256' }, { userId: 123, role: 'admin' });

// Example token output:
// ABR7ImFsZyI6IlJTQS1TSEEyNTYifQAdeyJ1c2VySWQiOjEyMywicm9sZSI6ImFkbWluIn1JG1YPNJNfZ2jA29DcqiU_HojNAC34mz0ueYYOZ45nbHg86Q_Q7RULHsQfMp1tn0AdeGC9gStX1QK-fCB7Qgt3kF85qCtlDcYywDrjwmg19H0XnWeD27fXCOmmcM-rLjkVe61WDEb8rktmtlMJAUtivDYJr8RxyI2kQF-ZddlrgukjzRtua2_FmWmohb5MeahhfQ6xmlM1HRbYSMlUBaGjSxx_Q4s3wNrpMNDWiDM0adA1iHH5h00VRo2t5iepytOY3YunEW3_UXKcqr9PZ8KV-ikW2mXXp45Xw39U96dkeD3M9dR3vexL8yBc8kNDeT6a8YpHb63HW8s6LUlV_jzB

// Verify a token
try {
  const decoded = auth.verifyToken(token);
  console.log('Decoded:', decoded);
  /* 
  Output: 
  { 
    header: { alg: 'RSA-SHA256' }, 
    payload: { userId: 123, role: 'admin' } 
  }
  */
} catch (err) {
  console.error('Verification failed:', err.message);
}

How it works?

@jnode/auth provides a lightweight and binary-safe alternative to JWT, focusing on a straightforward token format encoded in base64url.

The token structure is as follows:

1. Header Length: 2 bytes (UInt16BE)
2. Header JSON: n bytes
3. Payload Length: 2 bytes (UInt16BE)
4. Payload JSON: n bytes
5. Signature: RSA-SHA256 signature of the preceding segments (bytes 1 through 4).

This format ensures that the token is self-contained and tamper-proof while being extremely efficient to parse without complex regex or split operations.

Reference

Class: auth.AuthService

The main class to handle signing and verification of tokens.

new auth.AuthService(publicKey, privateKey)

• publicKey <string> | <Buffer> | <KeyObject> The public key used for verification.
• privateKey <string> | <Buffer> | <KeyObject> The private key used for signing.

Static method: AuthService.signToken(header, payload, privateKey)

• header <Object> | <Buffer> Token header data. Default: {}.
• payload <Object> | <Buffer> Token payload data. Default: {}.
• privateKey <string> | <Buffer> | <KeyObject>
• Returns: <string> A base64url encoded token.

Signs the provided header and payload using the RSA-SHA256 algorithm.

Static method: AuthService.verifyToken(token, publicKey)

• token <string> | <Buffer> The token to verify.
• publicKey <string> | <Buffer> | <KeyObject>
• Returns: <Object> An object containing { header, payload }.

Parses and verifies the token. Throws an Error if the signature is invalid or TypeError if keys are missing.

service.signToken(header, payload)

• header <Object> | <Buffer>
• payload <Object> | <Buffer>
• Returns: <string>

Instance method that uses the privateKey provided in the constructor to sign a token.

service.verifyToken(token)

• token <string> | <Buffer>
• Returns: <Object>

Instance method that uses the publicKey provided in the constructor to verify a token.