Problem 1:
A) Alice, Bob and Charlie have a secret key a = 3, b = 4, c = 5, respectively.
B) They want to find a common secret key using Diffie-Hellan key exchange protocol (with g = 2, p = 5).
C) Assume that there is no man-in-the-middle attacker.
D) Show how they can share a common secret key with the above mentioned numbers.
Problem 2:
A) Encrypt and decrypt first 3 characters of your last name (family name) using RSA with the prime numbers (p = 7, q = 11).
(If your last name is shorter than 3 characters, use first 3 characters of your first name instead.)
Use ASCII code at: http://www.ascii.cl/
• e.g.) Michael Nordan
• A = 65, B = 66, …
• N -> 78, o->111, r->72
B) You can choose an encryption key e among {11, 13, 19, 23, 29} and find d.
C) You have to show the all the steps (in particular, EEA) as detail as possible.
D) Encrypt the message using your encryption key e like this way (n = pq):
If you number is greater than 76, decompose them into a smaller number as follows.
• e.g., 7 8 11 17 2
• (7^e) mod n
• (8^e) mod n
• (11^e) mod n
• (17^e) mod n
• (2^e) mod n
E) Decryption the ciphertext using private key d.