Suppose Alice and Bob use an Elgamal scheme with a common prime q = 157 and a primitive root a = 5. [10 points] If Bob has public key YB = 10 and Alice chose the random integer k = 5, what is the ciphertext of M = 9? [10 points] If Alice now chooses a different value of k so that the encoding of M = 10 is C = (25, C2), what is the integer C2?
Read DetailsIn an RSA encryption system, given that p=19 and q=23. The pair of keys (public [e], private [d]) needs to be generated from p and q. The choice of one of the two keys is with some freedom, and the choice of the other key is fixed after the first key is chosen. The pair of keys can be used to encrypt and decrypt messages.[5 points] If you are asked to first pick e among 6, 7, 8, 9, 10, and 11, then which value would you pick?[5 points] After you have picked e, what is the corresponding value of key d?[10 points] With the pair of keys (d, e), if another user wants to send to you a message, then which key should be used to encrypt message? If the plaintext is 8, then what is the value of the encrypted message?[10 points] With the pair of keys (d, e), if you are asked to show your true identity, then which key should be used to sign a message? If the plaintext is 8, then what is the value of the signed message?
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