(PHP 4, PHP 5, PHP 7)

mcrypt_get_block_sizeGets the block size of the specified cipher


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


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().

Elenco dei parametri


Una tra le costanti MCRYPT_ciphername, oppure il nome dell'algoritmo sotto forma di stringa.


Una tra le costanti MCRYPT_MODE_modename, oppure una tra le seguenti stringhe: "ecb", "cbc", "cfb", "ofb", "nofb" o "stream".

Valori restituiti

Returns the algorithm block size in bytes o FALSE in caso di fallimento.


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


Vedere anche:

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User Contributed Notes 1 note

mehaase at gmail dot com
2 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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