Mcrypt Functions
PHP Manual


(PHP 4, PHP 5, PHP 7)

mcrypt_get_block_sizeGets the block size of the specified cipher


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().



One of the MCRYPT_ciphername constants, or the name of the algorithm as string.


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.


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.


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


See Also

Mcrypt Functions
PHP Manual