The security of blockchain stems from the fact that it works on the basis of cryptography. Through its use, it is possible to enjoy the advantages of this technology, such as decentralisation or transparency. This branch of mathematics plays a fundamental role, bringing with it a number of benefits for the network and its users. In this article, we would like to tell you how asymmetric cryptography works. It will give you an insight into how public and private keys work and what mathematical solutions they are based on.

Asymmetric cryptography – definition and operation

Asymmetric cryptography is otherwise known as public key cryptography. It uses a pair of related keys to encode and decode content. This ensures data integrity, authenticity and confidentiality of communication. Messages encoded by the sender using a private key are decoded by the receiver using a public key. The processes take place automatically. They are authenticated using a digital signature. It confirms the consent of the signing party and provides proof of e.g. origin or status.

Public key cryptography finds its widespread application in communications, website operation and cryptocurrencies. In blockchain, it is used to sign transactions and secure funds - the private key is necessary to access the assets stored at a given address.

Curiosity: Before asymmetric cryptography, symmetric cryptography was used. Under it, encryption and decryption were done with a single key. The receiver and the sender had to make sure that a given key (the so-called secret key) did not fall into the wrong hands. Using it, they transformed an unintelligible text (ciphertext) into a readable message (plaintext).

Algorithms of public key cryptography

In asymmetric cryptography, a public key is created from a private key. The key creation methodologies can include the following:

RSA (Rivest-Shamir-Adleman) – it is one of the most common algorithms. It is based on a mathematical operation of factorising integers which are the product of prime numbers. RSA keys are either 1024 or 2048 bits long, but with advances in computing power, there is a slow move away from the first mentioned.

Elliptic curve cryptography (ECC) – it is an alternative to RSA. To decrypt this method, a potential attacker would have to calculate the Elliptic Curve Discrete Logarithm Problem (ECDPL), which is much more complex than the factorisation in RSA. This makes it much more secure and efficient.

History of asymmetric cryptography

This type of cryptography originated as early as the 20th century. In 1977, Whitfield Diffie and Martin Hellman, researchers at Stanford University, first published a scientific paper on the subject in the journal New Directions in Cryptography. The previously described RSA algorithm created by MIT researchers Ron Rivest, Adi Shamir and Leonard Adleman was published in Communications of the ACM in 1978. Over time, public key cryptography has gained increasing recognition, which has translated into the creation of regulations and standardisation related to its use in a variety of protocols.

Conclusion – the future of asymmetric cryptography

The increased need for security in the digital space is driving more and more sectors to use cryptography to protect themselves from threats. Developments in this area are inevitable - new types of cyber-attacks are being developed every day. The next milestone that cryptography will have to overcome is the progressive development of quantum computers, which have enormous computing power and would be able to solve encryption using, for example, the RSA algorithm. Nevertheless, with the advancement of science and the adoption of blockchain, cryptographic security is becoming stronger and stronger, and despite the enormous technological advancement, it is safe to say that there is still much to be discovered in this area.