I downloaded the free sample of
this dictionary. I tried opening it in FBReader and it said compression method not supported. Then I tried mobihuff.py and it said it's encrypted. Then I tried mobidedrm.py with igorsk's changes above and it said "invalid PID checksum" and created a 0-byte output file. I tried with versions 0.01, 0.02, 0.04 and 0.05 with no joy.
Is there any solution for decrypting this file? Note that it's a demo, I didn't give any PID to dowload it.