Parameters may seem obvius to some but not for everyone so:
- $data can be as the description says raw or base64. If no $option is set (this is, if value of 0 is passed in this parameter), data will be assumed to be base64 encoded. If parameter OPENSSL_RAW_DATA is set, it will be understood as row data.
- $password (key) is a String of [pseudo] bytes as those generated by the function openssl_random_pseudo_bytes().
- $options as (as for 2016) two possible values OPENSSL_RAW_DATA and OPENSSL_ZERO_PADDING. Setting both can be done by OPENSSL_RAW_DATA|OPENSSL_ZERO_PADDING. If no OPENSSL_ZERO_PADDING is specify, default pading of PKCS#7 will be done as it's been observe by [openssl at mailismagic dot com]'s coment in openssl_encrypt()
- $iv is as in the case of $password, a String of bytes. Its length depends on the algorithm used. May be the best way to generate an $iv is by:
<?php
$iv = openssl_random_pseudo_bytes(openssl_cipher_iv_length('your algorithm'));?>
