Abstract: Cryptography is the learning of system to transfer information securely among users. The security of information is the main concern in the wireless communication network. Cryptography is mainly used for confidentiality, key distribution, authentication, integrity and non repudiation. Private key cryptosystem and public key cryptosystem are commonly used crypto systems to transfer information securely. In this paper, we have compared five public key cryptosystem i.e. Elliptical Curve Cryptography (ECC), Diffie Hellman (DH), Elgamal Cryptographic System (ECS), RSA, and NTRU. Implementation of public key algorithms in very constrained devices such as mobile phones smart cards, PDA etc. demands faster cryptosystems. We have analyzed above public key cryptosystem and concluded that NTRU is the most efficient public key cryptosystem. NTRU public key cryptosystem is the fastest public key cryptosystem to provide different security levels at high speed with very constrained resources.
Keywords: Cryptography, Security, Encryption, Decryption, Asymmetric Encryption, AKA.