I did a reimplementation of the system (back when chaincodes existed).

However, you can also read the armory source itself.

It is a special hex encoding.

Instead of "0123456789abcdef" for the 16 values, it uses "asdfghjkwertuion".

These were picked so that there is less chance of a typo.

Each line is 16 data bytes + 2 CRC bytes.  This means that there are 36 characters (2 characters per byte).

The CRC is the first 2 bytes of SHA256(SHA256(data)).