(PHP 5 >= 5.3.0, PHP 7, PECL phar >= 1.1.0)
Phar::setSignatureAlgorithm — Set the signature algorithm for a phar and apply it
$sigtype
   ) : voidNote:
此方法需要 将 php.ini 中的
phar.readonly设为0以适合 Phar 对象. 否则, 将抛出PharException.
   Set the signature algorithm for a phar and apply it.  The
   signature algorithm must be one of Phar::MD5,
   Phar::SHA1, Phar::SHA256,
   Phar::SHA512, or Phar::PGP
   (pgp not yet supported and falls back to SHA-1).
  
sigtype
       One of Phar::MD5,
   Phar::SHA1, Phar::SHA256,
   Phar::SHA512, or Phar::PGP
      
没有返回值。
Throws UnexpectedValueException for many errors, BadMethodCallException if called for a zip- or a tar-based phar archive, and a PharException if any problems occur flushing changes to disk.