README

A lightweight encryption and decryption library built on top of OpenSSL, supporting:

• AES-128-CBC
• AES-256-CBC
• MAC validation (HMAC SHA-256)
• Secure payload structure (IV + value + MAC)
• String and serialized value encryption

Installation

composer require kishor-rajbanshi/php-crypt

Supported Ciphers

• AES-128-CBC (requires 16-byte key)
• AES-256-CBC (requires 32-byte key)

Generating a Key

use KishorRajbanshi\Crypt\Crypter;

$key = Crypter::generateKey('AES-256-CBC');

Basic Usage

Create Crypter Instance

use KishorRajbanshi\Crypt\Crypter;

$key = random_bytes(32); // 32 bytes for AES-256-CBC
$crypter = new Crypter($key, 'AES-256-CBC');

Encrypt & Decrypt Any Value (Serialized)

$data = ['name' => 'Kishor', 'role' => 'Developer'];

$encrypted = $crypter->encrypt($data);

$decrypted = $crypter->decrypt($encrypted);

print_r($decrypted);

Encrypt & Decrypt Strings Only (No Serialization)

$encrypted = $crypter->encryptString('Hello World');

$decrypted = $crypter->decryptString($encrypted);

Payload Structure

Encrypted payload is:

base64_encode(json_encode([
    'iv' => base64_encoded_iv,
    'value' => encrypted_value,
    'mac' => hmac_sha256
]))

The MAC ensures data integrity and prevents tampering.

Exception Handling

The package throws custom exceptions:

• KishorRajbanshi\Crypt\Exceptions\Encrypt
• KishorRajbanshi\Crypt\Exceptions\Decrypt

Example

use KishorRajbanshi\Crypt\Exceptions\Decrypt;
use KishorRajbanshi\Crypt\Exceptions\Encrypt;

try {
    $encrypted = $crypter->encrypt('Secret');
} catch (Encrypt $e) {
    echo "Encryption failed: " . $e->getMessage();
}

try {
    $decrypted = $crypter->decrypt($encrypted);
} catch (Decrypt $e) {
    echo "Decryption failed: " . $e->getMessage();
}

Key Length Validation

The constructor validates key length automatically:

• AES-128-CBC → 16 bytes
• AES-256-CBC → 32 bytes

If invalid, it throws:

RuntimeException

Security Notes

• Always store your encryption key securely.
• Never expose your key publicly.
• Rotate keys periodically if used in production.
• Do not modify encrypted payloads manually.

Running Tests

composer install
composer test

License

MIT