Essay On Classical Cryptography

I. INTRODUCTION

Classical cryptography is directly affected by these breakthroughs because it relies solely on the hardness of computing a mathematical problem that cannot be solved by current computers in polynomial time, but theoretically can be solved on a quantum computer. This realization is what spurred the research in quantum cryptography because quantum cryptography does not rely on computational security, but rather on the laws of quantum physics [4]. Cryptography means that we keep a message secret during transmission through untrusted and secure channel. Its simple means- encoding and decoding messages and has existed as long as people have distrusted each other and sought forms of secure communication. This encoding and decoding

It was shown, that as long as the key is truly random, has the same length as the message, and is never reused then the one-time pad is perfectly secure. So, if we have a truly unbreakable system.

What is wrong with classical cryptography?

In classical cryptography use the concept of key distribution. In this when the key is established, sub-sequent communication involves sending cryptograms over a channel. However in order to establish the key, two users, who share no secret information initially, must at a certain stage of communication use a reliable and very secure channel.[1]

In principle any classical key distribution can always be passively monitored, without the legitimate users being aware that any eavesdropping has taken place. In classical cryptography concept use the secret key encryption technique. Fig: encryption concept [1]

The interesting solution for the concept of key distribution problem proposed by the Whitfield Diffie and Martin Hellman.

It involved two keys, one public key for encryption and one private key for