Term for property of functions $f$ anf $g$ for which $f(g(x)) = x$

I've just tried googling this extensively and I just can't seem to find the answer.

Let's say I have two functions $f$ and $g$ such that $f(g(x)) = x$ and $g(f(y)) = y$, is there a name for this property? (Beyond $f$ is the inverse function of $g$?)

As a more concrete example I am thinking of encrypting/decrypting a value with some key:

$decrypt(encrypt(x, key), key) = x$

$encrypt(decrypt(y, key), key) = y$

"symmetric" was my first guess but as I understand it that applies to functions with the property $h(h(x)) = x$ and not two different functions.