An encryption algorithm based on alphabetic trees

Summary form only given. Optimal alphabetic trees (OATs) are known to be used in several application areas, such as coding, probabilistic retrieval systems and VLSI design. In this paper, we introduce a novel encryption algorithm, alphabetic tree cipher (ATC), based on an interesting property of OATs. A theorem is presented to define a family of weight lists that all have the same OAT of a given weight list (and consequently the same level values). Considering the plain text to be the original weight list, a key is used to select one from the family of equivalent weight lists to be the cipher text. While finding the levels of the cipher text is easy, finding the corresponding plain text without knowledge of the key is not. The security of the algorithm is analyzed and discussed under different block encryption modes, and against different kinds of attacks.