Lesson 3

Question 1

symmetric cryptography

Answer 1

A cryptography system that uses a single shared encryption key to encrypt and decrypt data. Best suited for bulk encryption

Question 2

Symmetric Cryptography formula

Answer 2

N(N-1)/2 = number of keys needed

Question 3

Two types of symmetric algorithms

Answer 3

Stream Cipher / Stream Algorithm

Block Cipher / Block Algorithm

Question 4

XOR Stream Cipher

Answer 4

An exclusive disjunction, which means that it produces an output of truth
(or 1) whenever the two inputs differ (such as one is a zero [false] and the other is a one [true]).

Question 5

C32 BRAIDS

Answer 5

C ast 128 / 256 (64 bit/128 bit)
3 DES 2-112 bit / 3-168 bit (48 Rds)
2 fish 128 bit
B lowfish 64 bit
R C 4 (Stream and WEP) 5,6 (Block)
A ES 128 bit Block (128/10)(192/12)(256/14)
I DEA 64 bit Block / 128 key
D ES 64 bit Block / 56 bit key (8 bit parity)
S afer+, Safer++

Symmetric Algorithms

Question 6

3DES

Answer 6

A standard that uses three iterations of DES with two or three different
keys to increase the effective key strength to 112 bits

Question 7

Advanced Encryption Standard (AES)

Answer 7

The encryption standard selected in October
2000 by the National Institute of Standards and Technology (NIST) that is based on the
Rijndael cipher.

Question 8

Escrowed Encryption

Answer 8

Trusted 3rd party keeps copy of private key pair

Provide a balance between privacy and the needs of law enforcement

Question 9

Clipper Chip

Answer 9

Used 80 bit symmetric encryption with the Skipjack algorithm (classified up

Question 10

asymmetric key

Answer 10

A form of cryptography that does not use symmetric keys. It either uses complex formulas to solve problems (such as Diffie-Hellman to generate/exchange symmetric
keys) or uses key pair sets to provide digital signatures and digital envelopes.

Question 11

DEER

Answer 11

D iffie-Hellman
E CC
E lGamal
R SA

Asymmetric Algorithms

Question 12

Hashed Message Authentication Code (HMAC)

Answer 12

An algorithm that implements a partial
digital signature—it guarantees the integrity of a message during transmission, but it does
not provide for nonrepudiation

Question 13

A forward-looking
concept that has no publicly known current real-world applications or uses. The idea is to take advantage of the dual nature of light at the quantum level, where it acts both as a wave and as a particle

Answer 13

quantum cryptography

Question 14

A hierarchy of trust relationships that makes it possible to
facilitate communication between parties previously unknown to each other

Answer 14

public-key infrastructure (PKI)