Symmetrical encryption

Using one key for encrypt and decrypt data. This library has default method set to aes-256-gcm

Encrypt text as follows

Copy$csp = new AESCryptoServiceProvider();
$csp->generateIV();
$key = $csp->generateKey();

$plainText = "This is going to be encrypted!";
$encryptedText= $csp->encrypt($plainText);

And then you can decrypt text as example shows bellow

Copy$csp2 = new AESCryptoServiceProvider();
$csp2->setKey($key);
$decryptedText = $csp2->decrypt($encryptedText);

Keep your key safe because you need it to decrypt data. You don't need to remember IV (initialization vector) because it is generated for each encryption, and then it is part of encrypted data.