Started GitHub project
base45 is a PHP based base45 encoder/decoder that is fully compatible with draft-faltstrom-base45-03.

Introduction
When using QR or Aztec codes a different encoding scheme is needed than the already established base 64, base 32 and base 16 encoding schemes that are described in RFC RFC4648. The difference from those and base 45 is the key table and that the padding with '=' is not required.

Check it out on GitHub: https://github.com/mhauri/base45