(PHP 4 >= 4.0.2, PHP 5)

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


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


Одна из констант MCRYPT_ciphername или название алгоритма в виде строки.


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.


Пример #1 mcrypt_get_iv_size() Example

echo mcrypt_get_iv_size(MCRYPT_CAST_256MCRYPT_MODE_CFB) . "\n";

mcrypt_get_iv_size('des''ecb') . "\n";

Смотрите также


The size of the initialization vector (iv) will be returned in bytes NOT bits, something to keep in mind specially if the iv is passed together appended or prepended with the encrypted data for decryption
2016-06-28 08:45:53

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