# Computes the SHA1 of the receiver.
	#
	# Returns a 40 char String containing the Hexadecimal
	# Digest in its Char form.
	#
	#     assert "The quick brown fox jumps over the lazy dog".sha1_hexdigest == "2FD4E1C67A2D28FCED849EE1BB76E7391B93EB12"
	fun sha1_hexdigest: String do return sha1.hexdigest