It is documented, flexible, and fast, and comes with a BSD license.
Homepage: http://github.com/froydnj/binascii
Author: Nathan Froyd
binascii
binascii is a binary format library for converting binary data to ASCII
text of some kind. Such conversions are common in email protocols (for
encoding attachments to support old non-8-bit clean transports) or
encoding binary data in HTTP and XML applications. binascii supports
the encodings described in RFC 4648:
base64, base32, base16, and variants. It also supports base85, used in Adobe's PostScript
and PDF document formats, and a variant called ascii85,
used by git for binary diff files.