Public Key Encryption Explained Along With Its Advantages And Disadvantages

Cryptography or cryptology is the art and study of passing information without the intrusion of prying eyes. History suggests that this method has been prevalent for centuries, from the ancient Greeks to the World War era; however, its contemporary form is still used in modern digital communication and computer security authentication. The inexplicable failure of traditional encryption (symmetric cryptography) in terms of computer security and data reliability, forced scientists around the world to change something that would eliminate these shortcomings. Therefore, public key encryption (the brainchild of Whitfield Diffie and Martin Hellman) was introduced in 1976; which in the realm of cryptography, raised computer security to a whole new level.

What is it?

In traditional (symmetric) cryptography, when the sender sends an indecipherable message to the recipient, both parties use the same secret key to lock / unlock the message. Now here is the problem. The secret key, which would be used by both parties, must be delivered through some or other means. Therefore, there is no guarantee that the key can travel without unsolicited manipulation, putting data integrity at risk.

Public key encryption was the imminent solution to this problem. In this technique, both parties receive a unique public and private key pair. These keys work hand in hand to protect and decode the desired information. The public key is freely available, while the private key, as its name suggests, is confidential and protected by its respective owner. One of the most prominent examples could be the RSA algorithm. RSA is an acronym for Rivest, Shaman, and Alderman, who wrote this algorithm.

How does it work?

As stated above, public key encryption revolves around the concept of two keys. Let’s imagine the following scenario.

A wants to send an encrypted message to B. They both have a key pair mentioned above. A looks up B’s public key in the directory. Once found, it creates your digital signature by calculating your private key and the actual message. That done, it encrypts the message and sends it to B, which in turn is verified by B through some calculations with the message, signature and public key of A. Consequently, if the calculations at the end of B prove that the signature is authentic, the message is decoded; otherwise, it is considered tampered or the signature has been forged. This technique practically eliminates the problem of data encryption for information security.

Pros and cons

The most significant advantage of this type of encryption is optimal security and ease of use. In addition, each user is responsible for protecting their private key, which provides complete independence of ownership. At the same time, this system reduces the risks of widespread forgery by decentralizing keys. In fact, this process is called non-repudiation. On the other hand, this cryptographic technique also has a couple of drawbacks. It is comparatively slower than a couple of advanced encryption techniques. This is due to its long computational time to factor large numbers while encoding, decoding, and authenticating messages. Also, public key encryption like RSA is virtually impossible to crack due to its complex algorithm. This proves to be a major setback for security personnel who want to track the security breach of confidential data of a company or government organization.

The sudden increase in information security has forced cryptographers to find better and updated solutions every day.