Crypt

Overview:

Crypt provides symmetric encryption using libsodium (preferred) or OpenSSL as fallback. It completes the security stack alongside Hash, Password, Token, and CSRF.

Key behavior:

• Uses sodium_crypto_secretbox when available (PHP 7.2+), falls back to aes-256-gcm via OpenSSL.
• Each encryption generates a random nonce, so encrypting the same data twice produces different ciphertexts.
• Keys are hex-encoded strings generated by Crypt::key().
• Output is base64-encoded for safe storage and transport.

Public API:

• Crypt::encrypt($data, $key) — encrypt plaintext, returns base64-encoded ciphertext.
• Crypt::decrypt($ciphertext, $key) — decrypt, returns plaintext or false on failure.
• Crypt::key() — generate a new random encryption key (hex string).
• Crypt::available() — check if encryption is available.

Example:

// Generate a key (store this securely)
$key = Crypt::key();

// Encrypt
$encrypted = Crypt::encrypt('sensitive data', $key);

// Decrypt
$plain = Crypt::decrypt($encrypted, $key);
// 'sensitive data'

// Wrong key returns false
$wrong = Crypt::decrypt($encrypted, Crypt::key());
// false