Abstract
Internet has become a global means of communication, turned our reality upside down. It has transformed communications, to the level that it is now our chosen standard of communication. Although there are many ways to protect information from undesired access, Quantum cryptography can be used to unconditionally secure data communications by applying the laws of quantum physics which overcomes the drawbacks of traditional classical cryptography, which depends on mathematical methods to limit attacks such as eavesdroppers. Quantum cryptography is considered to be a future replica of classical cryptography. In this survey paper, we will discuss about various protocols of cryptography. Also discussing about their vulnerabilities.