(PHP 5 >= 5.3.0)
openssl_digest — Computes a digest
Computes a digest hash value for the given data using a given method, and returns a raw or binhex encoded string.
Warning本函数还未编写文档，仅有参数列表。
The data.
The digest method.
Setting to TRUE will return as raw output data, otherwise the return value is binhex encoded.
Returns the digested hash value on success 或者在失败时返回 FALSE.
Emits an E_WARNING level error if an unknown signature algorithm is passed via the method parameter.