Use of Cryptography in communication

This work envisages the presentation and analysis of important cryptographic systems in the field as well as the way these systems have been applied during the course of time. The work presents the advantages and disadvantages that derive from the use of cryptography while also emphasizing the importance cryptography has had along the way. Not least, the present article shall analyze the ?Pretty Good Privacy? model ? a widely used system nowadays, whose decryption key has yet to be found.