OpenSSL Functions
PHP Manual

openssl_cipher_iv_length

Gets the cipher iv length

Description

intfalse openssl_cipher_iv_length(string $cipher_algo)

Gets the cipher initialization vector (iv) length.

Parameters

cipher_algo

The cipher method, see openssl_get_cipher_methods for a list of potential values.

Return Values

Returns the cipher length on success, or false on failure.

Errors/Exceptions

Emits an E_WARNING level error when the cipher algorithm is unknown.

Examples

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