openssl_cipher_iv_length

Gets the cipher iv length

&reftitle.description; ``int``false```openssl_cipher_iv_length` `string` `cipher_algo`

Gets the cipher initialization vector (iv) length.

&reftitle.parameters;

`cipher_algo`

- The cipher method, see `openssl_get_cipher_methods` for a list of potential values.

&reftitle.returnvalues;

Returns the cipher length on success, or &false; on failure.

&reftitle.errors;

Emits an `E_WARNING` level error when the cipher algorithm is unknown.

&reftitle.examples;

### `openssl_cipher_iv_length` example

    <?php
    $method = 'AES-128-CBC';
    $ivlen = openssl_cipher_iv_length($method);

    echo $ivlen;
    ?>

&example.outputs.similar;

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