Tom Crypto

Cryptographic utilities for secure authentication and data protection.

Features

• **JWT Tokens** - Token-based authentication with HMAC/RSA signing and encrypted payloads
• **Password Hashing** - Secure password storage using Argon2 algorithm
• **RSA Encryption** - Asymmetric encryption with OAEP padding and digital signatures
• **RSA Key Management** - Key generation, PEM parsing/encoding (PKCS#1 and PKCS#8)

Getting Started

Add the package to your `pubspec.yaml`:

dependencies:
  tom_crypto: ^1.0.0

Usage

Password Hashing

import 'package:tom_crypto/tom_crypto.dart';

// Hash a password
final (hash, spec) = TomPasswordHasher.hashPassword('userPassword123');

// Store both hash and spec in your database
await db.saveUser(passwordHash: hash, hashSpec: spec);

// Verify the password later
if (TomPasswordHasher.verifyPassword('userPassword123', hash, spec)) {
  print('Login successful!');
}

JWT Tokens

import 'package:tom_crypto/tom_crypto.dart';

// Server: Create a token
final token = TomServerJwtToken(
  {'userId': '123', 'role': 'admin'},
  encryptedData: {'permissions': ['read', 'write', 'delete']},
  expiresIn: Duration(hours: 24),
);
final jwtString = token.getJWT('my-auth-server');

// Client: Parse the token
final clientToken = TomClientJwtToken(jwtString);
print('User ID: ${clientToken.payload?['userId']}');
print('Permissions: ${clientToken.secretData?['permissions']}');

RSA Encryption

import 'package:tom_crypto/tom_crypto.dart';
import 'dart:convert';
import 'dart:typed_data';

// Generate keys
final secureRandom = RsaKeyHelper.getSecureRandom();
final keyPair = await RsaKeyHelper.computeRSAKeyPair(secureRandom);
final publicKey = keyPair.publicKey as RSAPublicKey;
final privateKey = keyPair.privateKey as RSAPrivateKey;

// Encrypt
final plaintext = utf8.encode('Secret message');
final encrypted = rsaEncrypt(publicKey, Uint8List.fromList(plaintext));

// Decrypt
final decrypted = rsaDecrypt(privateKey, encrypted);
final message = utf8.decode(decrypted);

Core Components

Component	Purpose	Key Features
`jwt_token.dart`	Token-based authentication	HMAC/RSA signing, encrypted payloads
`password_hashing.dart`	Secure password storage	Argon2 algorithm, configurable parameters
`rsa_encryption.dart`	Asymmetric encryption	OAEP padding, digital signatures
`rsa_tools.dart`	RSA key management	Key generation, PEM parsing/encoding

Additional Information

This package is part of the TOM Framework. It depends on: - `tom_basics` - Basic utilities including exception handling

License

BSD-3-Clause - See [LICENSE](LICENSE) for details.