New public key techniques based on double discrete logarithm problem

This paper introduces three new public key algorithms . The main one-way trapdoor functions of these algorithms are the double discrete logarithm problem (DDLP) and the integer factorization problem (IFP).The first proposed algorithm depends on the DDLP while the second and third proposed algorithms depend simultaneously on both the DDLP and the IFP. The validity of these algorithms is proven by applying to messages that are either an integer or a text and returning the original message in various numerical examples. The proposed cryptosystems have many advantages that are explained in details.