Increasing the key length is one way to increase security of an encryption algorithm against the brute-force type of attack. DES uses 56-bit key, which is not secure, given the modern computing power. Assume that 80-bit key is just sufficient this year, and assume that the hardware performance improves about 40% per year, then until what year would a 128-bit AES key be sufficient?

please explain the answer and show the steps