Hashing

Question 1

What is hash value of MD5?

Answer 1

128

Note: Known to have collisions

Question 2

What is SHA-1’s hash value?

Answer 2

160

Question 3

What are the SHA-2 and SHA-3 hash values?

Answer 3

SHA-224
SHA-256
SHA-348
SHA-512

Question 4

SHA’s main competitor is RACE Integrity Primitive Evaluation Message Digest (RIPEMD) - What are its hash values?

Answer 4

160
256
320

Note: 160-bit is the most commonly used. It is open source, made to compete with SHA but not as popular.

Question 5

What does Hash-based Message Authentication Code (HMAC) do? How?

Answer 5

Uses a hash algorithm, to check the integrity of a message and authenticity.

It uses other hash algorithms to do the work.  
Exa:
HMAC-MD5
HMAC-SHA1
HMAC-SHA256

Question 6

How is a digital signature created?

Answer 6

The file/email to be sent, is hashed. The sender uses then uses their private key, and encrypts the hash. Then the email is sent, along with the encrypted hash.

Question 7

How do you verify a digital signature?

Answer 7

The receiver takes the digital signature and decrypts it with the senders public key to reveal the hash value before decryption. The receiver then takes the original message and hashes it with the same hash algorithm. If the hash value is the same as the one in the digital signature, then the message is authentic and can not be repudiated.

Question 8

What hash algorithms are used for digital signatures?

Answer 8

DSA (Digital Security Algorithm)
RSA
ECDSA (Elliptic Curve DSA)
SHA

Question 9

What other uses are digital signatures good for?

Answer 9

Code signing of software code to verify it hasn’t been modified or tampered with after it was submitted by the developer.

Note: Apple and Google send each developer a private key that must be used to digitally sign the code of their mobile app install file.

Question 10

What is the first HASH algorithm that was used to protect passwords?

Answer 10

LANMAN Hash (LM Hash).

Used by Windows, based on the DES algorithm. It is only 14 characters long. Super not safe. Still exists but it is auto-disabled in Windows.

Note: OOOLLLD. Was made in the 80’s. Don’t turn it on unless you have a VERY good reason.

Question 11

What is the second HASH algorithm for passwords?

Answer 11

NT LAN Manager Hash (NTLM Hash)

Uses RC4. Still exists but it is auto-disabled in Windows.

Note: Used in the of Windows NT 3.1, back in 1993.

Question 12

What is the current HASH algorithm used to store passwords?

Answer 12

NTLMv2 Hash

Uses HMAC-MD5 and is difficult to crack. This is used for Windows computers that do not use Kerberos.

Question 13

Exam Tips

Answer 13

Hashing is used to ensure integrity. If you see a question about integrity on the exam, instantly think of hashing.

Remember that MD5 and SHA are the most commonly used hash functions. Also remember that MD5 is less secure than SHA.