https://tools.ietf.org/html/rfc4648#section-8
https://tools.ietf.org/html/rfc4648#section-6
https://en.wikipedia.org/wiki/Base32#Crockford's_Base32
https://tools.ietf.org/html/rfc4648#section-7
https://tools.ietf.org/html/rfc4648#section-4
https://tools.ietf.org/html/rfc4648#section-5
http://philzimmermann.com/docs/human-oriented-base-32-encoding.txt