This module provide 3 convenience functions to calculate the digest
of files. The following functions are provided:
digest_file( $file, $algorithm, [$arg,...] )
This function will calculate and return the binary digest of the bytes
of the given file. The function will croak if it fails to open or
read the file.
The $algorithm is a string like "MD2", "MD5", "SHA-1", "SHA-512".
Additional arguments are passed to the constructor for the
implementation of the given algorithm.
digest_file_hex( $file, $algorithm, [$arg,...] )
Same as digest_file(), but return the digest in hex form.