A bijection `f`

is a function which is both an
injection and a
surjection.
For each bijection `f:X→Y`

we can define its inverse `f`

where
^{-1}Y→X`f`

if ^{-1}(y)=x`f(y)=x`

.

The function `f(x)=x`

is a bijection.

A. Menzes, P. van Oorschot, and S. Vanstone, *Handbook of Applied Cryptography.* CRC Press, 1996.

Copyright © 2014 Barry Watson. All rights reserved.