# Understanding Cryptography by Christof Paar and Jan Pelzl - Chapter 3 Solutions - Ex3.2

- 1 min- Return to index
- Exercise 3.1
- Exercise 3.2
- Exercise 3.3
- Exercise 3.4
- Exercise 3.5
- Exercise 3.6
- Exercise 3.7
- Exercise 3.8
- Exercise 3.9
- Exercise 3.10
- Exercise 3.11
- Exercise 3.12
- Exercise 3.13

## Exercise 3.2

We want to verify that and are truly inverse operations. We consider a vector of 64 bit.

Show that for the first five bits of , i.e. for .

### Solution

*I haven’t yet verified this solution independently. If you spot any mistakes, please leave a comment in the Disqus box at the bottom of the page.*

The easiest way to demonstrate this is to create a table that shows which location each bit gets mapped to after each operation: