Let $F$:$\{0,1{\}}^n\{0,1{\}}^{2n}\{0,1{\}}^{2n}$ be a pseudorandom permutation and define an encryption scheme for messages of length $n,$ where the key klarr

PS$2,$ Page $1$

$\{0,1{\}}^n$ is sampled uniformly at random, and the encryption algorithm Enc samples rlarr$\{0,1{\}}^n$ and computes $En{c}_k(m)=F_k(r||m)o+1^n.$ Show how to decrypt, and prove that this scheme is CPA$-$secure$.$