(PHP 5 >= 5.3.3, PHP 7, PHP 8)
openssl_cipher_iv_length — Gets the cipher iv length
$cipher_algo): int|falseGets the cipher initialization vector (iv) length.
cipher_algoThe cipher method, see openssl_get_cipher_methods() for a list of potential values.
Returns the cipher length on success, or false on failure.
Emits an E_WARNING level error when the cipher algorithm
is unknown.
Example #1 openssl_cipher_iv_length() example
<?php
$method = 'AES-128-CBC';
$ivlen = openssl_cipher_iv_length($method);
echo $ivlen;
?>
The above example will output something similar to:
16