Finding Slid Pairs for the Plantlet Stream Cipher
Joshua Copeland, Leonie Ruth Simpson · Proceedings of the Australasian Computer Science Week Multiconference · 2020
This paper presents the results of an investigation into relationships between (key, IV) pairs that give rise to phase shifted keystreams for the stream cipher Plantlet. We demonstrate that such slid pairs exist for Plantlet, and that very small phase shifts are possible, including shifts of length 1. We also show that the keyspace can be partitioned into sets of keys which give rise to initial states that lie on the same state cycle during keystream generation. For a given key used to generate Plantlet keystreams, we provide a method for generating all other keys that give rise to phase shifted keystreams as they move through internal states on the same state cycle.