Babatunde, A. O.Adewole, K. S.Abdulraheem, M.Oniyide, S. A.2017-11-232017-11-232014http://hdl.handle.net/123456789/39A cryptosystem describes the system where two or more individuals communicate in a secret manner over a public channel. The contents of information shared on a public network need to be protected against unauthorized access using a more secured technique of encryption and decryption. A cipher is the heart of a cryptosystem, which specifies the policy for encryption and decryption. The encryption policy takes the plaintext and a predetermined key, and produces a ciphertext which hides the true meaning of the original plaintext. The decryption policy takes another key, which may be different from the encryption key, and recovers the plaintext from the ciphertext. In this paper, a cryptosystem is developed using Elgamal algorithm for key exchange purpose during information sharing on a public network. The proposed system provides a secure platform for encrypting and decrypting user's key. This key could be used by a symmetric algorithm for file encryption and decryption. The system is found capable of securing user's key from illegal access by an unauthorized person.enCryptosystem; Cipher; Elgamal; Encryption; DecryptionArticle