Cryptography

Question 1

Diffie-Hellman groups

Answer 1

Diffie-Hellman group 1—768 bit group
Diffie-Hellman group 2 —1024 bit group
Diffie-Hellman group 5—1536 bit group
Diffie-Hellman group 14—2048 bit group
Diffie-Hellman group 19—256 bit elliptic curve
Diffie-Hellman group 20—384 bit elliptic curve group

Question 2

Which of the algorithms provides better protection against brute force attacks by using a 160-bit message digest?

Answer 2

SHA-1

Question 3

MD5

Answer 3

Can be cracked by brute-force attack and suffers from extensive vulnerabilities

Question 4

RC4

Answer 4

is ideal for software implementation

Question 5

MD4

Answer 5

used to verify data integrity through the creation of a 128-bit message digest from data input

Question 6

Which optimized for confidential communications, such as bidirectional voice and video

Answer 6

RC4 enables safe communications such as traffic encryption (which secures websites) and for websites that use the SSL protocol.

Question 7

Advanced encryption standard ( AES ) is an algorithm used for

Answer 7

Bulk data encryption

Question 8

Which contains a public key and the identity of the owner and the corresponding private key is kept secret by the certification authorities

Answer 8

Signed certificates

Question 9

popular CAs

Answer 9

Comodo, IdenTrust, Symantec, and GoDaddy

Question 10

Cross certification

Answer 10

enables entities in one PKI to trust entities in another PKI

Question 11

Which Describes a component of public key infrastructure (PKI) where a copy of a private key is stored to provide third-party access and to facilitate recovery operations?

Answer 11

Key escrow

Question 12

Which element of public key infrastructure (PKI) verifies the applicant?

Answer 12

Registration authority (RA): This acts as the verifier for the certificate authority.

Question 13

Which Cryptography attack methods is usually performed without the use of a computer?

Answer 13

Rubber Hose attack

Question 14

Which cryptanalysis methods is applicable to symmetric key algorithms?

Answer 14

Differential cryptanalysis

Question 15

In which attack can an attacker obtain ciphertexts encrypted under two different keys and gather plaintext and matching ciphertext?

Answer 15

Related-key attack. The related-key attack is similar to the chosen plaintext attack except that the attacker can obtain ciphertexts encrypted under two different keys

Question 16

An attacker breaks an n bit key cipher into 2 n/2 number of operations in order to recover the key. Which cryptography attack is he performing?

Answer 16

Chosen-key attack

Question 17

Which attack is a physical attack that is performed on a cryptographic device/cryptosystem to gain sensitive information?

Answer 17

Side channel attack

Question 18

Which of the following attacks mainly affects any hardware/software using an ANSI X9.31 random number generator (RNG)?

Answer 18

DUHK attack

Question 19

attack that is used for cracking a cryptographic algorithm using multiple keys for encryption.

Answer 19

Meet-in-the-middle Attack

Question 20

SHA-512 encryption uses ____ bit words

Answer 20

64

Question 21

The Encrypted information is known as a ____

Answer 21

Cipher