original source of pydes class is from https://github.com/RobinDavid/pydes Using DES class is only a small part in whole incremetal cryptography/ authentication.
original source of doubelLL is from https://www.geeksforgeeks.org/doubly-linked-list/ For implementing privacy enhanced dna-storage I used above DLL implemetation; again DLL is only a small aspect of implemented algorithm.