Q:

What would be a simple example of an asymmetric encryption function (asymmetric function)?

I am trying to understand RSA encryption but the algorithm seems quite complex.
I know that with asymmetric encryption you use a key and a function to encrypt data and a different function to decrypt it.
I understand the xor-ing used in most basic symmetric algorithms (functions). The same key (a series of bits of the same length as the plain data is used to encrypt and decrypt). This is possible because the xor function is symmetric (from what I know).
What are some examples of asymmetric functions? What is the function that you use to encrypt and what is the function you use to decrypt and how do you compute the second argument of the function (the first one being the data you are trying to encrypt/decrypt)?

A:

RSA is about the simplest known instance of asymmetric encryption. There are a few others, but all of them rely on mathematics.
Symmetric encryption is easy (conceptually), because it is just about making a big knot with the data, and remembering how the knot was made; with that knowledge (that's the "key") you can untie the knot, basically by undoing all operations in reverse order.
Asymmetric encryption requires something magical. If you want to go with the knot metaphor, then it is a kind of knot where even knowing how things were tied up does not reveal how to untie them. In cryptographic terms, it must not be feasible to recover the private key (which is the power to decrypt data), even if the public key (the power to encrypt data) is known. Private and public key share a common mathematical structure, since one decrypts what the other encrypts, but that structure must resist analysis.
In this answer, I tried to explain RSA in simple terms. If you want to understand asymmetric cryptography, then you have to grasp enough mathematics to understand RSA. The good news is that such knowledge is not that hard, and it is reusable. So I encourage you to work up your algebra. Basically, you have to get familiar with the notion of computing things "modulo" an integer.

