Booklet Type: D 1. AES algorithm uses 128 bits long inputs: what it the plaintext is not elivisible by 128 ? This is known as a.The Spacing Droblem brthe Padding Problem c. The Chaining Problem d. The hexify Problem 2. The main disadvantage of private key cryptenystems (DES or AES) is that the private key must be exchanged. able to exchange private keys over a public channel arsubstitution b. Diffie Hellman algorithm. c.rermatation d.One time pad 3. In the private key never needs to be exchanged. g.iprivate Key Cryptography b.Private Cryptography c.Public Cryptography d.Public Key Cryptography 4. Is very similar to Caesar cryptosystem but we use several keys instead of just a single key. a.DES IraEs cVigenerecipher 5. is an involution so the function's inverse is the function itself. g.xof b.OR CAND d.NAND 6. In theory it is impossible to break a BUT: 1. generating perfectly random numbers (as keys) is extremely hard, 2. the key has the same length as the plaintext. 2.DES brone timepad cars d.RSA 7. We can generate with these algorithms: 1.) middle-square method, 2.) Mersenne twister, 3.) linear congruential generators a.ptime numbers b perfect numbers epseudo-random numbers dkey numbers 8. If an unauthorized party counterfeits an asset, this threat is called. a. Medification b.interruption conterception d.Fabrication 9... Is a hidden, self-replicating section of computer software, usually malicious logic, that propagates by infecting (i.e., inserting a copy of itself into and becoming part of) another program. a.Vires b. Trejan harse clogic bomb d.Trapdoor 10. We can use the AIS algorithm like this with several modes, In mode we use AES on every 128 bits long plaintext hlock. These blocks are independent of each other so we use AES separately on every block. z.CEC(Cpher block Chainina) b.CFB (Cipher FeedBack) COFB (Output FeedBack) d.ECB ( Electronic Code Book) 11. According to If we change a single bit in the input (plaintext) then half of the digits in the output (ciphertext) should change. a. Ronfusion b.Substitution coiffusion d. Permutation 12. is a trapdoor function: validating the result by multiplying two numbers is quite easy but finding the factors is haird. a.Integer factorization btuler's (n) function c.Coprime factorization dimodular inverse 13. is defined as "A flaw or weakness in a system's design, implementation, or operation and management that could be exploited to violate the system's security policy." a.Countermeasure briulnerability c.Risk d.Asset 14 is a private key cryptosystem with three different keylenghts 128,192 and 256. a.AES b.DES done time pad 15. According to each binary digit of the ciphertext should depend on several digits of the private key. a.Diffusion b.Substitution spermutation d. Confusion 16 is the process of encoding a given message in a way that only the authorized parties can access it. a.Plaintext b.Ciphertext cetncryption d.Decryption 17 Is the type of cryptography that uses just a single key. So the same key is used both for encryption and decryption as well. offrivate Key Cryptography b.Private Cryptography c.Public Key Cryptography d.Public Cryptography 18. has a so called Feistel-structure with Block size: 64 bits, Key size: 64 bits ( 56 relevant bits are used in the algorithm), Number of rounds: 16, Number of subkeys: 16 (every subkey is 48 bits long) and Ciphertext size: 64 bits. a.OES b.AES c.RSA d.one time pad 19. Deep Crack has managed to crack with brute-force attack within 22 hours. a.AES B.RSA c.DES gone time pad 20.... ... is a block cipher BUT it has nothing to do with Feistel structure, it stores the values (plaintext, key, ciphertext) in matrix form. a.DES b.AES C.RSA done time pad
