This module provides functions to encode and decode strings into and from
the base64 encoding specified in RFC 2045 - MIME
(Multipurpose Internet Mail Extensions).
The base64 encoding is designed to represent arbitrary sequences of octets
in a form that need not be humanly readable.
A 65-character subset ([A-Za-z0-9+/=]) of US-ASCII is used, enabling 6 bits
to be represented per printable character.