An asymmetric key is a feature of asymmetric cryptography, also known as public-key cryptography, which is a method of encrypting and decrypting data using two different keys: a public key and a private key. The public key can be shared with anyone, while the private key must be kept secret by the owner. The public key and the private key aremathematically related, but it is computationally infeasible to derive one from the other. Asymmetric cryptography can be used for various purposes, such as digital signatures, key exchange, and encryption. For example, if Alice wants to send a message to Bob, she can use Bob’s public key to encrypt the message, and only Bob can decrypt it using his private key. Alternatively, if Bob wants to prove that he is the author of a message, he can use his private key to sign the message, and anyone can verify it using his public key. Asymmetric cryptography has some advantages over symmetric cryptography, which uses the same key for both encryption and decryption. For instance, asymmetric cryptography does not require a secure channel to distribute the keys, and it can provide non-repudiation and authentication. However, asymmetric cryptography also has some drawbacks, such as higher computational complexity, larger key sizes, and higher network overhead.
References:
ISA/IEC 62443-3-3:2018, Section 4.2.3.6.1, Cryptography1
ISA/IEC 62443-4-2:2019, Section 4.2.3.6.1, Cryptography
ISA/IEC 62443 Cybersecurity Fundamentals Specialist Study Guide, Section 5.3.1, Cryptography
ISA/IEC 62443 Cybersecurity Fundamentals Specialist Exam Specification, Section 5.3.1, Cryptography
