CRYPTO

Question 1

DES

Answer 1

Block Cipher / 56 bits / Weak

Question 2

3DES

Answer 2

Block Cipher / 56*3 bits(168) / Slower

Question 3

AES

Answer 3

Block Cipher / 128/192/256 bits / Faster than 3DES

Question 4

IDEA

Answer 4

Block Cipher / 128bits /

Question 5

Twofish

Answer 5

Block Cipher / up to 256 bits

Question 6

BlowFish

Answer 6

Fast Block Cipher / 64bits / replaced by AES

Question 7

RC4

Answer 7

Stream Cipher / 1-256 bits / Used in TLS or WEP, no recommended

Question 8

RC5

Answer 8

Block Cipher / up to 2048 bits

Question 9

Diffie-Hellman

Answer 9

Asymectric / > 2048bits / Shared secret in an insecure channel, used in SSL and IPSec encryption

Question 10

RSA

Answer 10

Asymetric / > 2048 bits / Prime number, encryption and digital signatures, standard

Question 11

ECC (Elliptic Curse Cryptosystem)

Answer 11

Asymetric encryption cipher, good choice for mobile cause it’s usedless processing power than other method

Question 12

El Gamal

Answer 12

Asymetric encryption cipher

Question 13

DUHK attack

Answer 13

refers to a vuln that allow attacker access to keys in certain VPN

Question 14

FREAK attack

Answer 14

downgrade RSA key

Question 15

POODLE

Answer 15

a hacker jump in conversation and downgrade cipher to SSL V3 (using RC4)

Question 16

Heartbleed

Answer 16

read 64bits (like password), version openssl 1.0.1 and 1.0.1f is vulnerable, cve: CVE-2014-0160

Question 17

known plaintext attack

Answer 17

the attacker get both plaintext and cipher text

Question 18

chosen plaintext attack

Answer 18

attacker select a plaintext and check the cipher text