Returns the verification signature of a phar archive in a hexadecimal string.
Return Values
Array with the opened archive's signature in "hash" key and "md5" or "sha1"
in "hash_type". This signature is a hash calculated on the
entire phar's contents, and may be used to verify the integrity of the archive.
A valid signature is absolutely required of all phars if the
phar.require_hash INI variable
is set to true.