Cryptography

Question 1

What is the standard required for handling credit card information?

Answer 1

PCI DSS (Payment Card Industry Data Security Standard)

Question 2

What do you call the encrypted plaintext?

Answer 2

Ciphertext

Question 3

What do you call the process that returns the plaintext?

Answer 3

Decryption

Question 4

RSA math: n is what?

Answer 4

the product of p and q (p * q)

Question 5

RSA Math: p and q?

Answer 5

Large primenumbers (300 digits)

Question 6

RSA math: Public key is?

Answer 6

n and e (n,e)

Question 7

RSA math: Private key is?

Answer 7

n and d (n,d)

Question 8

RSA math: Representation of plaintext message?

Answer 8

m

Question 9

RSA math: Representation of the encrypted messsage?

Answer 9

c

Question 10

RSA math: ϕ(n) = ?

Answer 10

n - p - q + 1

Question 11

[Forklar] Diffie-Helman Key Exchange

Answer 11

Person A og B har adgang til et fællesmateriale (p og g, hvorom der gælder: p skal være et primtal, og der skal gælde at 0 < g < p)
Person A og B vælger hver deres secret key (a & b), som skal være en integer.
A = g^a mod p
B = g^b mod p
Person A sender A
Person B sender B
Key eller secret kan nu kommes frem til:
key = B^a mod p
key = A^b mod p

Question 12

Diffie-Helman math: Formel for the secret key?

Answer 12

A^b mod p = secret

Question 13

[Forklar] Hvad er cryptography?

Answer 13

It is the science of securing communication and data using codes and ciphers.

Question 14

[Forklar] Hvad er cryptanalysis

Answer 14

It is the study of methods to break or bypass cryptographic security systems without knowing the key.

Question 15

[Forklar] Hvad er Brute-Force Attack

Answer 15

It is an attack method that involves trying every possible key or password to decrypt a message

Question 16

[Forklar] Dictionary Attack

Answer 16

It is an attack method where the attacker tries dictionary words or combinations of them

Question 17

[ABB] Hvad står SHA for?

Answer 17

Secure Hashing Algorithm

Question 18

[ABB] Hvad står MD-5 for?

Answer 18

Message-Digest Algorithm 5

Question 19

[CMD] How do you show NUMBER LINE in a text file?

Answer 19

sed -n ‘NUMBERp’ <file.txt></file.txt>

Question 20

[CMD] Anvend Hashcat på et hash som er $2a$06$7yoU3Ng8dHTXphAg913cyO6Bjs3K5lBnwq5FJyA6d01pMSrddr1ZG
og crack den.

Answer 20

Hashcat.net -> 2a (bcrypt -> hash code 3200)
hashcat -m 3200 -a 0 hashfile wordlist

Question 21

[Eksemplificer!] Kom med eksempler på to hjemmesider man kan bruge til at cracke hashes med

Answer 21

Crackstation.com & hashes.com

Question 22

[Tools] Nævn nogle tools indenfor cracking!

Answer 22

HASHCAT og HASHid