Question 1

The security of the Kerberos server should not automatically be assumed but must be guarded carefully by taking precautions such as placing the server in a locked room.

Accepted Answer

The security of the Kerberos server is crucial for ensuring the protection of network resources and user authentication. Simply assuming that the server is secure can lead to vulnerabilities and potential breaches. Precautions such as placing the server in a locked room can help to enhance its security and reduce the risk of unauthorized access or tampering.

Question 2

________ is a procedure that allows communicating parties to verify that the contents of a received message have not been altered and that the source is authentic.
A)Identification
B)Message authentication
C)Verification
D)User authentication

Accepted Answer

Message authentication is the procedure that verifies that the contents of a received message have not been altered and that the source is authentic. Identification refers to the act of recognizing who the communicating party is. Verification is a more general term that can refer to multiple types of procedures, and user authentication specifically refers to the process of verifying the identity of a user.

Question 3

Any timestamp based procedure must allow for a window of time sufficiently large enough to accommodate network delays yet sufficiently small to minimize the opportunity for attack.

Accepted Answer

Timestamp based procedures rely on synchronized clocks to ensure that transactions occur in a specific order. However, network delays can cause clocks to drift apart, which can lead to errors or vulnerabilities. To mitigate these issues, a window of time is typically introduced to account for potential delays. This window must be carefully balanced to ensure that delays are accommodated without giving attackers a large enough window of opportunity to exploit.

Question 4

User authentication is the means by which a user provides a claimed identity to the system.

Accepted Answer

The answer of User authentication is the means by which...

Question 5

A common item of authentication information associated with a user is a ___________ .
A)nonce
B)timestamp
C)ticket
D)password

Accepted Answer

A password is a commonly used authentication information associated with a user, which is kept secret and known only by the user. Nonce, timestamp, and ticket are also used for various authentication protocols and systems, but they are not as commonly associated with a user as a password is.

Question 6

There are a variety of problems including dealing with false positives and false negatives,user acceptance,cost,and convenience with respect to biometric authenticators.

Accepted Answer

Biometric authenticators have several issues such as false positives and false negatives, user acceptance, cost, and convenience.

Question 7

The __________ approach is unsuitable for a connectionless type of application because it requires the overhead of a handshake before any connectionless transmission,effectively negating the chief characteristic of a connectionless transaction.
A)timestamp
B)backward reply
C)challenge-response
D)replay

Accepted Answer

The challenge-response approach involves a handshake between the sender and receiver before any transmission takes place. This approach is suitable for connection-oriented applications, but not for connectionless applications. The overhead of the handshake would negate the chief characteristic of a connectionless transaction, which is the lack of a dedicated, continuous connection between the sender and receiver. The other options (timestamp, backward reply, and replay) do not necessarily require a handshake and could be suitable for use in a connectionless application.

Question 8

The operating system cannot enforce access-control policies based on user identity.

Accepted Answer

The operating system can enforce access-control policies based on user identity through user authentication and authorization mechanisms.

Question 9

__________ is an authentication service designed for use in a distributed environment.
A)Kerberos
B)PCBC
C)Toklas
D)X.509

Accepted Answer

Kerberos is a widely used authentication protocol for providing secure access to network resources. It is designed to work in distributed environments and uses symmetric key cryptography to authenticate clients and servers, and to establish secure communication channels between them. Kerberos is widely used in enterprise environments, and is supported by various operating systems and applications. The other options provided (PCBC, Toklas, X.509) are not specifically designed for use in distributed environments, and are not widely used for authentication.

Question 10

An e-mail message should be encrypted such that the mail handling system is not in possession of the decryption key.

Accepted Answer

This is true as it ensures that only the intended recipient can decrypt and read the message, thus ensuring confidentiality and privacy.

Question 11

Kerberos provides a trusted third party authentication service that enables clients and servers to establish authenticated communication.

Accepted Answer

Kerberos is a widely used authentication protocol that allows clients and servers to authenticate each other and establish secure communication with the help of a trusted third-party called the Kerberos Key Distribution Center (KDC). This trusted third-party authentication service enables secure communication in a network by issuing a ticket granting ticket (TGT) to the client after successful authentication, which grants access to other network resources without requiring the user to enter credentials repeatedly.

Question 12

Identity federation is in essence an extension of identity management to multiple security domains.

Accepted Answer

Identity federation allows for the sharing of identity information between different security domains, allowing for seamless access to resources across multiple systems.

Question 13

For network based user authentication the most important methods involve cryptographic keys and something the individual possesses,such as a smart card.

Accepted Answer

The answer of For network based user authentication the most...

Question 14

Because there are no potential delays in the e-mail process timestamps are extremely useful.

Accepted Answer

While timestamps can be useful, potential delays in email delivery can occur due to server issues, network congestion, or other factors, making timestamps not always reliable for precise timing.

Question 15

Examples of dynamic biometrics include recognition by fingerprint, retina,and face.

Accepted Answer

The answer of Examples of dynamic biometrics include recognition by...

Question 16

The overall scheme of Kerberos is that of a trusted third party authentication service that uses a protocol based on a proposal by __________ .
A)Needham and Schroeder
B)Kehn
C)Denning
D)Gong

Accepted Answer

Kerberos protocol is based on the Needham-Schroeder protocol proposal for secure key exchange between two parties over an insecure network, which was later extended by both Needham and Schroeder and Bellovin and Merritt to include a trusted third-party authentication service.

Question 17

It is the ticket that proves the client's identity.

Accepted Answer

A ticket does not prove a client's identity. Other forms of identification, such as a driver's license or passport, are typically required for identity verification.

Question 18

Once the server verifies that the user ID in the ticket is the same as the unecrypted user ID in the message it considers the user authenticated and grants the requested service.

Accepted Answer

Once the server verifies the user ID in the ticket and the unencrypted user ID in the message, it considers the user authenticated and grants the requested service.

Question 19

Identity providers may also assign attributes to users,such as roles,access permissions,and employee information.

Accepted Answer

The answer of Identity providers may also assign attributes to...

Question 20

User authentication is the basis for most types of access control and for user accountability.

Accepted Answer

User authentication verifies the identity of a user who wants to access a system, service, or application. Once authenticated, the user is granted access based on their permissions and privileges. User authentication is essential for controlling access to sensitive information and ensuring that users are held accountable for their actions.

Quiz 15: User Authentication Protocols