OpenSSL Functions
PHP Manual

openssl_cipher_iv_length

(PHP 5 >= PHP 5.3.3, PHP 7)

openssl_cipher_iv_lengthGets the cipher iv length

Description

int openssl_cipher_iv_length ( string $method )

Gets the cipher initialization vector (iv) length.

Parameters

method

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

OpenSSL Functions
PHP Manual