2.1. The stream cipher described in Definition 2.1.1 can easily be generalized to work in alphabets other than the binary one. For manual encryption, an especially useful one is a stream cipher that operates on letters. 1. Develop a scheme which operates with the letters A, B,..., Z, represented by the numbers 0,1,...,25. What does the key (stream) look like? What are the encryption and decryption functions? 2. Decrypt the following cipher text: bsaspp kkuosp which was encrypted using the key: rsidpy dkawoa 3. How was the young man murdered?