Saturday, September 6, 2025
HomeLanguagesPHP openssl_cipher_key_length() Function

PHP openssl_cipher_key_length() Function

The openssl_cipher_key_length() function is an inbuilt function in PHP that is used to retrieve the key length required for a given cipher algorithm.

Syntax:

openssl_cipher_key_length(string $cipher_algo): int|false

Parameters: This function accepts only one parameter which is described below.

  • $cipher_algo: This is a string representing the cipher algorithm.

Return Values: The function returns an integer representing the length in bytes of the key required for the given cipher algorithm, or “false” on failure. 

Example 1: The following program demonstrates the openssl_cipher_key_length() function.

PHP




<?php
$cipher = "bf-cbc";
$key_len = openssl_cipher_key_length($cipher);
echo "Key length for {$cipher}: {$key_len}\n";
?>


Output:

Key length for bf-cbc: 16 

Example 2: The following program demonstrates the openssl_cipher_key_length() function.

PHP




<?php
$cipher = "AES-256-CBC";
$key_length = 24;
  
if ($key_length === openssl_cipher_key_length($cipher)) {
    echo "The key length is valid for $cipher.";
} else {
    echo "The key length is not valid for $cipher.";
}
?>


Output:

The key length is not valid for AES-256-CBC. 

Reference: https://www.php.net/manual/en/function.openssl-cipher-key-length.php

Whether you’re preparing for your first job interview or aiming to upskill in this ever-evolving tech landscape, neveropen Courses are your key to success. We provide top-quality content at affordable prices, all geared towards accelerating your growth in a time-bound manner. Join the millions we’ve already empowered, and we’re here to do the same for you. Don’t miss out – check it out now!
RELATED ARTICLES

Most Popular

Dominic
32270 POSTS0 COMMENTS
Milvus
82 POSTS0 COMMENTS
Nango Kala
6639 POSTS0 COMMENTS
Nicole Veronica
11805 POSTS0 COMMENTS
Nokonwaba Nkukhwana
11869 POSTS0 COMMENTS
Shaida Kate Naidoo
6754 POSTS0 COMMENTS
Ted Musemwa
7029 POSTS0 COMMENTS
Thapelo Manthata
6705 POSTS0 COMMENTS
Umr Jansen
6721 POSTS0 COMMENTS