Chapter 6: Hashing and Digital Signature

Question 1

is a security method that scrambles a message into a fixed length string without the possibility of turning it back to its original form.

Answer 1

Hash(ing) or Message Digest

Question 2

is also a basic component of digital signature.

Answer 2

Hash

Question 3

is a one-way function that takes a message of arbitrary length as input and produces fixed-length bit string as output.

Answer 3

Hash Function

Question 4

is the possibility of two different messages that would result to the same hash value.

Answer 4

Collision

Question 5

is a concept under Probability theorem, that states that in a set of randomly chosen people, some pair of them will have the same birthday.

Answer 5

Birthday Paradox

Question 6

this principle state that if a number of items are put into a set of containers, then at least one container will contain more than one item.

Answer 6

Pigeon Hole Principle

Question 7

is a mathematical algorithm that maps data of arbitrary size (message) to a bit array of a fixed size.

Answer 7

Cryptographic Hash Function (CHF)

Question 8

[3] Common Examples of Hash Algorithm

Answer 8

1. Message Digest Algorithm (MD5)
2. Secured Hash Algorithm 1 (SHA 1)
3. Secured Hash Algorithm 2 (SHA 2

Question 9

a hash function that produces 128-bit hash value for arbitrary length.

Answer 9

Message Digest Algorithm (MD5)

Question 10

designed the Message Digest Algorithm.

Answer 10

Ronald Rivest (1991)

Question 11

a cryptographic hash function which takes an input and produces 160-bit(20-byte) hash.

Answer 11

Secured Hash Algorithm 1 (SHA 1)

Question 12

is a family that consists of six hash function with digests that are 224, 256, 384, or 512 bits.

Answer 12

Secured Hash Algorithm 2 (SHA 2)

Question 13

[3] Application of Hash Functions

Answer 13

• Password Protection
• Checksum / Integrity Check
• Digital Signature

Question 14

Desirable Properties of Hash Algorithm

Answer 14

1. Randomness
2. Avalanche Effect
3. Strict Avalanche Criterion

Question 15

[3] Tests perform to evaluate randomness

Answer 15

o Correlation Test

o Run Test

o Compute for the Mean and Variance and Independence of Probability

Question 16

[2] Tests performed to evaluate Avalanche Effect

Answer 16

o Confusion Test
o Diffusion Test

Question 17

test the effect of the key to the ciphertext.

Answer 17

Confusion Test

Question 18

test the effect of the plaintext to the ciphertext.

Answer 18

Diffusion Test

Question 19

at least 50%-bit flip in the ciphertext per one bit flip in the input.

Answer 19

Strict Avalanche Criterion

Question 20

has the same authentication and legally binding function as handwritten signature.

Answer 20

Digital Signature

Question 21

[3] Advantages of Digital Signature

Answer 21

• Authenticity (signed by real signatory)
• Integrity (document is not altered)
• Non-Repudiation

Question 22

[3] Major Components of a Digital Signature

Answer 22

1. Digital Document / File
2. Hash Algorithm
3. Encryption Algorithm

Question 23

the file that is needed to be digitally signed.

Answer 23

Digital Document / File

Question 24

this is to ensure that the document is not altered.

Answer 24

Hash Algorithm -