(PHP 5 >= 5.3.0, PHP 7)
openssl_digest — Computes a digest
$data
   , string $method
   [, bool $raw_output = false
  ] )Computes a digest hash value for the given data using a given method, and returns a raw or binhex encoded string.
本函数还未编写文档,仅有参数列表。
dataThe data.
methodThe digest method.
raw_output
       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.