Returns the size of the IV belonging to a specific cipher/mode combination


(PHP 4 >= 4.0.2, PHP 5)

mcrypt_get_iv_sizeReturns the size of the IV belonging to a specific cipher/mode combination

Описание

int mcrypt_get_iv_size ( string $cipher , string $mode )

Gets the size of the IV belonging to a specific cipher/mode combination.

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

Список параметров

cipher

Одна из констант MCRYPT_ciphername или название алгоритма в виде строки.

mode

Одна из констант MCRYPT_MODE_modename, либо одна из следующих строк: "ecb", "cbc", "cfb", "ofb", "nofb" и "stream".

The IV is ignored in ECB mode as this mode does not require it. You will need to have the same IV (think: starting point) both at encryption and decryption stages, otherwise your encryption will fail.

Возвращаемые значения

Returns the size of the Initialization Vector (IV) in bytes. On error the function returns FALSE. If the IV is ignored in the specified cipher/mode combination zero is returned.

Примеры

Пример #1 mcrypt_get_iv_size() Example

<?php
    
echo mcrypt_get_iv_size(MCRYPT_CAST_256MCRYPT_MODE_CFB) . "\n";

    echo 
mcrypt_get_iv_size('des''ecb') . "\n";
?>

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