Section 8.72 Hashing

Question 1

Hashing

Answer 1

One-way cryptographic function that takes an input and produces a unique message digest as its output

Question 2

Hash Digest

Answer 2

■ Like a digital fingerprint for the original data

■ Always of the same length regardless of the input’s length

Question 3

Common Hashing Algorithms

SHA (Secure Hash Algorithm) Family

Answer 3

● SHA-1
○ Produces a 160-bit hash digest, less prone to collisions than MD5

● SHA-2
○ Offers longer hash digests (SHA-224, SHA-256, SHA-348, SHA-512)

● SHA-3
○ Uses 224-bit to 512-bit hash digests, more secure, 120 rounds of computations

Question 3

Common Hashing Algorithms

MD5 (Message Digest Algorithm 5)

Answer 3

● Creates a 128-bit hash value

● Limited unique values, leading to collisions

● Not recommended for security-critical applications due to vulnerabilities

Most popular over the last few decades

Question 4

Common Hashing Algorithms

RIPEMD (RACE Integrity Primitive Evaluation Message Digest)

Answer 4

Versions available
○ 160-bit (Most common)
○ 256-bit
○ 320-bit

● Open-source competitor to SHA but less popular

Question 5

Common Hashing Algorithms

HMAC (Hash-based Message Authentication Code)

Answer 5

● Checks message integrity and authenticity

● Utilises other hashing algorithms (e.g., HMAC-MD5, HMAC-SHA1,
HMAC-SHA256)

Question 6

Digital Signatures

Answer 6

Created by hasing a file and then taking the resulting hash digest and encrypting it with a private key

■ Recipient decrypts the digital signature using the sender’s public key

■ Verifies integrity of the message and ensures non-repudiation

Question 7

Common Digital Signature Algorithms

DSA (Digital Security Algorithm)

Answer 7

Utilised for digital signatures

● Uses a 160-bit message digest created by DSS (Digital Security Standard)

Governmetn uses this

Question 8

Common Digital Signature Algorithms

RSA (Rivest-Shamir-Adleman)

Answer 8

● Supports digital signatures, encryption, and key distribution

● Widely used in various applications, including code signing

○ Hashes change drastically even with minor changes in input

○ Hashing is used to verify data integrity and detect any changes

Commercial use