RSKEY Encoding and Correction.
Change Parity to increase or decrease the error detection and correction capacity of
the RSKEY. It takes 1 parity symbol to correct any missing symbol (eg. one not
yet entered on the end of the RSKEY, or one replaced by an '_' or other invalid
character). 2 parity symbols are consumed to correct any erroneous symbol.
Change Data to regenerate the RSKEY. Provide either 0x... (hex), or Unicode text.