8. Suppose that the ciphertext DVE CFMV KF NFEUVI, REU KYRK ZJ KYV JVVU FW JTZVETV was pro- duced by encrypting a plaintext message using a shift ci- pher. What is the original plaintext?

Encrypt the message KILLTHEBEAST using shift cipher with K=18.

Suppose the RSA cryptosystem is used with public key (35, 7). What is the corresponding cipher text when the plain text "2" is sent? O 23 15 12 O 8

The ciphertext OIKYWVHBX was produced by encrypting a plaintext message using the Vigen`ere cipher with key HOT. What is the plaintext message?

Suppose that you know that a ciphertext was produced by encrypting a plaintext message with a transposition cipher. How might you go about breaking it?

Use the RSA cipher with public key (n, e) = (713, 43) to encrypt the word "TEE." Start by encoding the letters of the word "TEE" into their numeric equivalents. Assume the letters of the alphabet are encoded as follows: A = 01, 8 = 02, C = 03, ..., Z = 26. Since the code for T is 20 and since e = 43 = 32 + 8 + 2 + 1, the first letter of the encrypted message is found by computing 2043 mod 713. 20¹a (mod 713) 20² Eb (mod 713) 204 c (mod 713) 208 d (mod 713) 2032 = f (mod 713) 2016 e (mod 713) b = The result is that a = C = d = e = and f = Thus, 2043 mod 713 = (a · b. d. f) mod 713 = So the first number in the encrypted message is Repeat these computations for each letter to find the complete encrypted message and enter your answer below. (Enter the message as a sequence of integer triples separated by a single space, where each triple is written using a fixed number of digits: 001 for 1, 002 for 2, ..., 099 for 99.)

Suppose an RSA cryptosystem is used to send the plaintext 4" with public key (n, e) = : (33, 3) What is the ciphertext that corresponds to the message "4?" 4 15 28 31

Use a Caesar cipher with a shift of 5 right to encrypt the following message: Meet me in Alabama. Write the final code in 4 letter blocks. Original A Маps Uv w XYZ B CD E F G H L P T X Y F G H K L NOPQ R U V W A В DE To a RIJY RJNS FQFG FRF RIJY RJNS FQGF FRE RJJY RJNS FQFG RFF d RJYJ RJNS FQFG FRF O O O O

Suppose (n, d) = (55, 3) is the private key of an RSA cryptosystem. If the received ciphertext is C = 49 what is the corresponding plaintext? O 3 4 10 14

Decrypt the ciphertext message “LEWLYPLUJL PZ H NYLHA ALHJOLY” that was encrypted with the shift cipher with shift k = 7.