CHAPTER 17: TRANSPORT-LEVEL SECURITY
TRUE OR FALSE
T F 1. A TLS session is an association between a client and a server.
T F 2. Secure Sockets Layer (SSL) is an Internet standard that evolved
from a commercial protocol known as Transport Layer Security
(TLS).
T F 3. Sessions are used to avoid the expensive negotiation of new
security parameters for each connection that shares security
parameters.
T F 4. The Handshake Protocol is the simplest of the four TLS-specific
protocols that use the TLS Record Protocol.
T F 5. The World Wide Web is fundamentally a client/server application
running over the Internet and TCP/IP intranets.
T F 6. One way to classify Web security threats is in terms of the location
of the threat: Web server, Web browser, and network traffic
between browser and server.
T F 7. The encryption of the compressed message plus the MAC must
increase the content length by more than 1024 bytes.
T F 8. The Change Cipher Spec Protocol is one of the four TLS-specific
protocols that use the SSL Record Protocol.
T F 9. The SSL Record Protocol is used before any application data is
transmitted.
T F 10. The first element of the CipherSuite parameter is the key exchange
method.
T F 11. The certificate message is required for any agreed on key
exchange method except fixed Diffie-Hellman.
T F 12. Phase 3 completes the setting up of a secure connection of the
Handshake Protocol.
T F 13. The shared master secret is a one-time 48-byte value generated
for a session by means of secure key exchange.
T F 14. SSL/TLS attacks can be grouped into four general categories:
attacks on the handshake protocol, attacks on the record and
application data protocols, attacks on the PKI, and other attacks.
T F 15. Server authentication occurs at the transport layer, based on the
server possessing a public/private key pair.
MULTIPLE CHOICE
1. The SSL Internet standard version is called _________ .
A) SSH B) HTTP
C) SLP D) TLS
2. The most complex part of TLS is the __________ .
A) SSL Record Protocol B) Handshake Protocol
C) Change Cipher Spec Protocol D) Alert Protocol
3. _________ attacks include impersonating another user, altering messages in transit
between client and server and altering information on a Web site.
A) Active B) Passive
C) Shell D) Psuedo
4. The symmetric encryption key for data encrypted by the client and decrypted by
the server is a _________ .
A) server write key B) client write key
C) sequence key D) master key
5. _________ provides secure, remote logon and other secure client/server facilities.
A) SLP B) HTTPS
C) TLS D) SSH
6. An TSL session is an association between a client and a server and is created by
the ___________ .
A) Handshake Protocol B) user
C) Spec Protocol D) administrator
7. An arbitrary byte sequence chosen by the server to identify an active or
resumable session state is a _________ .
A) peer certificate B) session identifier
C) compression D) cipher spec
8. The _________ is used to convey TLS-related alerts to the peer entity.
A) Change Cipher Spec Protocol B) Alert Protocol
C) SSL Record Protocol D) Handshake Protocol
9. With each element of the list defining both a key exchange algorithm and a
CipherSpec, the list that contains the combination of cryptographic algorithms
supported by the client in decreasing order of preference is the __________ .
A) CipherSuite B) Random
C) Session ID D) Version
10. Phase _________ of the Handshake Protocol establishes security capabilities.
A) 4 B) 1
C) 2 D) 3
11. The __________ approach is vulnerable to man-in-the-middle attacks.
A) Anonymous Diffie-Hellman B) Fixed Diffie-Hellman
C) Remote Diffie-Hellman D) Synchronous Diffie-Hellman
12. The final message in phase 2, and one that is always required, is the ___________
message, which is sent by the server to indicate the end of the server hello and
associated messages.
A) server_done B) no_certificate
C) goodbye D) finished
13. A ______ is an identifier of a user of TCP.
A) protocol B) port
C) seed D) shell
14. A PseudoRandom Function takes as input:
A) a secret value B) an identifying label
C) a seed value D) all of the above
15. _________ is organized as three protocols that typically run on top of TCP for
secure network communications and are designed to be relatively simple and
inexpensive to implement.
A) SSL B) SSH
C) TLS D) SSI
SHORT ANSWER
1. __________ uses Diffie-Hellman or Elliptic Curve Diffie-Hellman for key
exchange and does not permit RSA.
2. The _________ Protocol allows the server and client to authenticate each other
and to negotiate an encryption and MAC algorithm along with cryptographic
keys to be used to protect data sent in a TLS Record.
3. _________ attacks include eavesdropping on network traffic between browser
and server and gaining access to information on a Web site that is supposed
to be restricted.
4. The TLS Record Protocol provides two services for TLS connections:
confidentiality and ___________ .
5. The _________ takes an application message to be transmitted, fragments the
data into manageable blocks, optionally compresses the data, applies a MAC,
encrypts, adds a header, and transmits the resulting unit in a TCP segment.
6. __________ refers to the combination of HTTP and SSL to implement secure
communication between a Web browser and a Web server.
7. Two important TLS concepts are the TLS session and the TLS _________ .
8. Three standardized schemes that are becoming increasingly important as
part of Web commerce and that focus on security at the transport layer are:
SSL/TLS, HTTPS, and _________.
9. Three higher-layer protocols defined as part of TLS are: The Handshake
Protocol, The Change Cipher Spec Protocol, and the __________ .
10. _________ would appear to be the most secure of the three Diffie-Hellman
options because it results in a temporary, authenticated key.
11. A signature is created by taking the hash of a message and encrypting it with
the sender’s _________ .
12. With __________ , the user’s SSH client receives traffic with a given destination
port number, places the traffic on the correct port and sends it to the
destination the user chooses.
13. _________ require a client write MAC secret, a server write MAC secret, a client
write key, a server write key, a client write IV, and a server write IV, which
are generated from the master secret in that order.
14. TLS makes use of a pseudorandom function referred to as __________ to expand
secrets into blocks of data for purposes of key generation or validation.
15. __________ allows the client to set up a “hijacker” process that will intercept
selected application-level traffic and redirect it from an unsecured TCP
connection to a secure SSH tunnel.
TRUE OR FALSE
MULTIPLE CHOICE
SHORT ANSWER