Symmetric Encryption

Question 1

Compute the inverse of the following permutation:
1 2 3 4 5 6
3 2 5 1 6 4

Answer 1

write it out

Question 2

What encryption standard was used before AES and why did it need to be changed?

Answer 2

Before AES there was DES (Data Encryption Standard). The encryption standard needed to be changed because advances in computing power made it vulnerable to exhaustive keysearch, as 2^56 keys are not enough nowadays.