Computer science: asymmetric encryption, part 1

Self-tutoring about computer science: the tutor mentions some theory about asymmetric encryption.

The following is according to my understanding.

Asymmetric encryption refers to the situation where, to encrypt plain text, one key is used, but to decrypt it, a different one is used. In such a case, the key to encrypt it is often public, which means anyone can discover how the plain text was encrypted. Yet, such knowledge does not enable decryption.

The reason asymmetric encryption is possible is that some mathematical operations don’t have inverses. Over the real numbers, addition, subtraction, multiplication (except by 0), and division do: for example, if someone knows what three times a number is, they can easily discover the number by dividing by three. Division is the inverse of multiplication.

Yet, when an operation doesn’t have an inverse, one can be shown the result of a calculation, and even what calculation was done, yet still can’t discover what the original value was. Such is why asymmetric encryption can work.

Source:

YouTube: BurningIceTech: CompTIA Security+ Full Course for Beginners – Module 3 – Appropriate Cryptographic Solutions

Forouzan, B.A. (2013). Data Communications and Networking. McGraw-Hill.