PHP 7.0.6 Released

mcrypt_get_block_size

(PHP 4, PHP 5, PHP 7)

mcrypt_get_block_sizeGets the block size of the specified cipher

Description

int mcrypt_get_block_size ( int $cipher )
int mcrypt_get_block_size ( string $cipher , string $mode )

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

Gets the block size, as an integer.

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

?>

See Also

User Contributed Notes

mehaase at gmail dot com
1 year 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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