Cisco Cisco Certifications 210-250 Questions & Answers

• Question 281:

  Which one of the following is the PKI operation that would likely cause out-of-band communication over the phone?

  A. The client checks with the CA to determine whether a certificate has been revoked.

  B. The client validates with the CA to determine if the peer that they are communicating with is the entity that is identified in a certificate.

  C. A new signed certificate is received by the certificate applicant from the CA.

  D. The CA administrator contacts the certificate applicant to verify enrollment data before the request can be approved.

  Correct Answer: D

• Question 282:

  What does a digital certificate certify about an entity?

  A. A digital certificate certifies the ownership of the public key of the named subject of the certificate.

  B. A digital certificate certifies the ownership of the private key of the named subject of the certificate.

  C. A digital certificate certifies the ownership of the symmetric key of the named subject of the certificate.

  D. A digital certificate certifies the ownership of the bulk encryption key of the named subject of the certificate.

  Correct Answer: A

• Question 283:

  What is the reason that a digital signature can be used to provide the authenticity of digitally signed data?

  A. Both the signer and the recipient must first agree on a shared secret key that is only known to both parties.

  B. Both the signer and the recipient must first agree on the public/private key pair that is only known to both parties.

  C. Only the signer has sole possession of the private key.

  D. Only the recipient has a copy of the private key to decrypt the signature

  Correct Answer: C

• Question 284:

  Which one of the following options was used by Diffie-Hellman to determine the strength of the key that is used in the key agreement process?

  A. DH prime number (p)

  B. DH base generator (g)

  C. DH group

  D. DH modulus

  Correct Answer: C

• Question 285:

  If a client connected to a server using SSHv1 previously, how should the client be able to authenticate the server?

  A. The same encryption algorithm will be used each time and will be in the client cache.

  B. The server will autofill the stored password for the client upon connection.

  C. The client will receive the same public key that it had stored for the server.

  D. The server will not use any asymmetric encryption, and jump right to symmetric encryption.

  Correct Answer: C

• Question 286:

  Which one of the following is the reason that asymmetric encryption is not used to perform bulk encryption?

  A. Asymmetric algorithms are substantially slower than symmetric algorithms.

  B. Asymmetric algorithms are easier to break than symmetric algorithms.

  C. Symmetric algorithms can provide authentication and confidentiality.

  D. Symmetric algorithms use a much larger key size.

  Correct Answer: A

• Question 287:

  How many encryption key bits are needed to double the number of possible key values that are available with a 40-bit encryption key?

  A. 41 bits

  B. 80 bits

  C. 120 bits

  D. 160 bits

  Correct Answer: A

• Question 288:

  Which one of the following methods of cryptanalysis should you use if you only have access to the cipher text messages (all of which have been encrypted using the same encryption algorithm), and want to perform statistical analysis to attempt to determine the potentially weak keys?

  A. birthday attack

  B. chosen-plaintext attack

  C. ciphertext-only attack

  D. chosen-ciphertext attack

  Correct Answer: C

• Question 289:

  Which one of the following options is the attack that can be used to find collisions in a cryptographic hash function?

  A. birthday attack

  B. chosen-plaintext attack

  C. ciphertext-only attack

  D. chosen-ciphertext attack

  Correct Answer: A

• Question 290:

  Which one of the following options describes the concept of small changes in data causing a large change in the hash algorithm output?

  A. butterfly effect

  B. Fibonacci effect

  C. keyed effect

  D. avalanche effect

  Correct Answer: D