So permutation is one of the first steps of one of the first techniques that we use when we generate a key and we want to use that key with the cipher algorithm. We take the key, and we use a permutation table that will take the original input and map it to another output. Let's make it a bit more visual a bit more graphical. So we have the original key, we have our permutation table. And now we decide due to the permutation table, that the bitstream that is value is zero, will map to a bit that its value is six, and a bit value of seven will map to a bit value of zero. So, are bit value of 000 which equals to zero will map to 110, which equals to six and a bit values that is 111.

That is all eight possible options, which is the value is seven will map to a bit value of zero. And so we change our key from its original value to another different value. This is one technique that is being used to make our key to make our cipher much more confusing for an attacker.