mcrypt_get_block_size

(PHP 4, PHP 5, PHP 7 < 7.2.0, PECL mcrypt >= 1.0.0)

mcrypt_get_block_size — Gets the block size of the specified cipher

Warning

This function has been DEPRECATED as of PHP 7.1.0 and REMOVED as of PHP 7.2.0. Relying on this function is highly discouraged.

Description

mcrypt_get_block_size(int $cipher): int|false

mcrypt_get_block_size(string $cipher, string $mode): int|false

The first prototype is when linked against libmcrypt 2.2.x, the second when linked against libmcrypt 2.4.x or 2.5.x.

mcrypt_get_block_size() is used to get the size of a block of the specified cipher (in combination with an encryption mode).

It is more useful to use the mcrypt_enc_get_block_size() function as this uses the resource returned by mcrypt_module_open().

Parameters

cipher: One of the MCRYPT_ciphername constants, or the name of the algorithm as string.
mode: One of the MCRYPT_MODE_modename constants, or one of the following strings: "ecb", "cbc", "cfb", "ofb", "nofb" or "stream".

Return Values

Returns the algorithm block size in bytes or false on failure.

Examples

Example #1 mcrypt_get_block_size() example

This example shows how to use this function when linked against libmcrypt 2.4.x and 2.5.x.

<?php

echo mcrypt_get_block_size('tripledes', 'ecb'); // 8

?>

User Contributed Notes 1 note

down

mehaase at gmail dot com ¶

9 years ago


You should explain that the block size is return in BYTES, not the more commonly used unit, bits. Many readers are not going to know the DES block size and figure this out on their own.

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