The total processing speed of microprocessors (based on clock rate and number of circuits) is
doubling roughly every year. Today, a symmetric session key needs to be 100 bits long to be considered
strong. How long will a symmetric session key have to be in 30 years to be considered strong? - 5mks

About 8086 microprocessor

_typically refers to the frequency at which a chip like a central processing unit (CPU) is running and is used as an indicator of the processor's speed. a) The ALU b) The clock rate x c) The program counter d) The register e) All of the above.

Consider a very simple symmetric block encryption algorithm in which 32-bits blocks of
plainext are encrypted using a 64-bit key. Encryption is defined as
C = (P⊕K0 ) ⊞ K1

where C = ciphertext, K = secret key, K0 = leftmost 64 bits of K, K1 = rightmost 64 bits of K,
⊕ = bitwise exclusive OR, and ⊞ is addition mod 264
.

a) Show the decryption equation. That is, show the equation for P as a function of C, K0,
and K1.
b) Suppose and adversary has access to two sets of plaintexts and their corresponding
ciphertexts and wishes to determine K. We have the two equations:

C = (P⊕K0 ) ⊞ K1 ; C’

= (P’⊕K0 ) ⊞ K1

First, derive an equation in one unknown (e.g., K0). Is it possible to proceed further to
solve for K0?