Internet History, Technology, and Security - Final

Final Exam

1. How did the top-secret computing technologies developed at Bletchley Park during World-War II impact computing technology after the war:

• The computer scientists used their knowledge of electronic computers to build the first generation of general purpose computers

2. What did Alan Turing contribute to Computer Science?

• He founded the field of Artificial Intelligence

3. What was the primary reason the Colossus computer was faster than the BOMBE computer?

• The Colossus computer used vacuum tubes instead or gears and relays

4. Which of the following was the greatest weakness of store-and-forward networks like BITNET?

• If your message was behind a large message it would have to wait until the large message was completed before it was sent.

5. Which of the following is most like a “packet” on the Internet?

• A postcard

6. What was the original “stated” intention of the National Science Foundation Network (NSFNet)?

• To connect scientists to supercomputers

7. Given the original five-year and 15 million dollar budget of the National Science Foundation Network (NSFNet), what was the expected speed of the national NSFNet backbone?

• 56 thousand bits per second

8. Which of the following is the best explanation as to why the web was invented at CERN?

• Well-funded smart people in a culture that was open and fun

9. Which of the following is something that Robert Cailliau and Tim Berners-Lee did not do?

• Invented the first object-oriented language (WWW++)

10. Where was the first web server in America in production on December 12, 1991?

• Stanford Linear Accelerator (SLAC)

11. What protocol was commonly used during 1990-1993 to organize and find information on the Internet that did not use the world-wide-web protocols?

• Gopher

12. Which of the following products could be thought of as the “early ancestor of the Mozilla Firefox browser”?

• NCSA Mosaic

13. Where was JavaScript developed at?

• Netscape

14. What is the purpose of the World-Wide-Web Consortium?

• Define standards for the web and avoid proprietary balkanization of the web

15. Why was the first product sold by Amazon books?

• Because there are over 3 million books in print

16. Which of the following is most similar to an Internet router?

• A train station

17. About how many separate physical connections (i.e. hops) will a packet cross on the Internet as it goes from University of Michigan to Stanford University?

• 15

18. What is the value of a layered network model?

• It allows a complex design problem to be broken into smaller manageable parts

19. What is the IETF?

• It is a coordinating body where the standards that define the inner workings of the Internet are developed and published

20. Which is the lowest layer in the TCP/IP network model?

• Link

21. Which of the following is a Link Layer address?

• 00:1f:5b:81:62:e7

22. Which of the following is *not* an attribute of the Internet (IP) Layer?

• It is designed to recover lost packets

23. What is the purpose of the TTL value in an IP packet?

• It ensures that a packet does not get stuck in an infinite loop in the Internet

24. Which of the following is a domain name?

• www.coursera.org

25. What problem did Van Jacobson solve in TCP?

• He invented the slow-start algorithm to keep systems from overloading a slow link

26. When we talk of the protocols that move data over the Internet, we talk of TCP/IP. Which of the following is FALSE about TCP/IP?

• IP makes use of TCP as its underlying transport mechanism

27. Secure TCP (TLS) is between which two layers?

• Application and Transport
Symantec CA

28. When you are using secure http and sending data between your computer and your bank’s computer, where is the data encrypted and decrypted?

• Encrypted in your computer and decrypted in the bank’s computer

29. Which of the following is a TCP port (such as port 80 for HTTP) most like?

• A telephone extension

30. Which of the following commands is part of the Hypertext Transport Protocol (HTTP)?

• GET

31. What is the problem with secret key distribution via the internet?

• We cannot all physically visit every web site and physically pick up a key book to work securely with that site

32. What does a cryptographic hash function do?

• It takes a block of data and computes a fixed-size bit string called the hash value

33. Which of the following is credited as one of the inventors of Public Key Cryptograhy in the 1970’s

• Whitfield Diffie

34. Which historical figure is credited with encrypting military messages using a simple “shifted alphabet”?

• Caesar

35. Which of the following are the steps to sign and send a message to insure that the message came from the sender and was not modified in transit?

• Append the shared secret to the message, compute the cryptographic hash of the message + secret, send the message + cryptographic hash across the internet

36. Which of the following statements is false

• Public key encryption cannot be broken

37. What is the mathematical underpinnings of public key encryption?

• Prime numbers

38. Considering the four-layer TCP/IP model, which two layers does Secure Sockets Layer (SSL) fit between?

• Application and TCP

39. If you are sending credit card information from a coffee shop WiFi to an Internet web site and later you find your credit card information has been stolen, which is the most likely scenario as to how your information was stolen?

• You did not use secure HTTP (https) at a coffee shop with an open WiFi
Symantec Corp.

40. Which of the following would be major a warning sign that indicates lax security practices when dealing with a site where you have an ID and Pasword?

• They can send you a mail message with the password you previously used to log in if you forget it

Internet History, Technology, and Security - Week 10

Security: Web Security

1. Which of the following is false about the two keys used in public key encryption?

• If you have the public key it is easy to compute the private key

2. When you are using secure http and sending data between your computer and your bank’s computer, where is the data encrypted and decrypted?

• Encrypted in your computer and decrypted in the bank’s computer

3. In regards to security, what do we assume about the Internet?

• That neither the routers nor the links between the routers are secure

4. This week we’ve updated our model of how we communicate information via the internet to add in a fifth mini-layer to the structure in order to protect the confidentiality of transmissions. What is the new list of layers and in what order do we list them?

• * Application

• * Secure Sockets

• * TCP

• * IP

• * Link

5. What is packet sniffing?

• Computers watching packets being transmitted across the network in hopes of finding important or valuable data

6.Which of the following is FALSE about using secure sockets (i.e. https) to send sensitive information like a credit card across the Internet?

• It is impossible to decrypt your data

7.Which of the following is NOT a major threat to your data when using secure sockets?

• Someone may see your public key

8. Which of the following is not an equivalent name to ‘digital certificate’?

• Private key certificate

9. What is a digital certificate?

• An electronic document used to give a public key an identity

10. What is a certificate authority?

• An entity that certifies the ownership of a public key by the named subject of the certificate

11. Which of the following is NOT an indicator of the effectiveness of Verisign as a certificate authority?

• Verisign publishes its private keys on a little-known web site only available to key owners

12. How does your computer typically know the public key of a certificate authority during secure communications?

• Manufacture setup

Internet History, Technology, and Security - Week 9

Security: Encrypting and Signing

1. Which of the following is true of security?

• Perfect security is achievable and requires a trade-off with cost

2. What is the difference between active and passive wiretapping?

• In passive wiretapping the network is snooped whereas in active wiretapping the network data is altered

3. Integrity is preserved if

• The information you receive is from who you think it is and has not been modified since it was sent

4.  Which of the following factors has the smallest effect on the strength of a cryptosystem?

• The data being transmitted

5. What is one possible advantage of public-key cryptosystems over secret-key ones?

• Public-key cryptosystems do not have the problem of secure key distribution

6.What does it mean if a cryptosystem is symmetric-key in nature?

• The key used for encryption is not the same as the key used for decryption

7. The following question is encrypted using a Caesar Cipher with a shift of 13. You can use www.rot13.com to decrypt the question.

• Jub vf perqvgrq nf orvat bar bs gur vairagbef bs Rgurearg?

• Bob Metcalfe

8. The following question is encrypted using a Caesar Cipher with a shift of 13. You can use www.rot13.com to decrypt the question and answers.

• Jung qbrf gur Gjvggre unfugnt #VUGF fgnaq sbe?

• Vagrearg Uvfgbel, Grpuabybtl, naq Frphevgl

9. What is the SHA-1 hash of the string below as computed by http://www.dr-chuck.com/sha1.php
The Transport Layer does retransmission

• 1399edc7e55f7be8dbc7024bcb8830527722e179

10. What does a cryptographic hash function do?

• It takes a block of data and returns a fixed-size bit string called the hash value

11. What critical element does simple digest-based Message Signing as described in lecture depend on?

• The sharing of a secret transported securely ‘out of band’

12. What is the problem with secret key distribution via the internet?

• The communication of the secret key is insecure

13. You are going to send the message below using shared secret of IHTS. Use http://www.dr-chuck.com/sha1.php to compute your message digest using the technique from lecture. What will the first six characters of the digest/signature that you send along with the message?

• Be sure to drink more Ovaltine

• 8b4258

14. Select the valid signed message(s) from Annie if your shared secret is IHTS? Use http://www.dr-chuck.com/sha1.php to compute your message digests using the technique from lecture. Only the first 6 characters of the SHA1 message digest are shown below. (Choose all that apply)

• Bring me cookies51be4e

• Everything is all right7dd244

Internet History, Technology, and Security - Week 8

Technology: Application Protocols

1. What does the Application Layer expect from the Transport Layer?

• A reliable pipe that delivers data from another application across the Internet

2. If you were “hacking” the Hypertext Transport Protocol using the ‘telnet’ command, what command would you send to the web server once you are connected to retrieve a document?

• GET

3. Which of the following are examples of applications in the application layer?

• Internet Explorer

• Chrome web browser

• Firefox

• Instant Messaging Client

• Microsoft Outlook

• Apple Mail

4. When is the Internet 100% up and working?

• It never is. It is constantly having pieces connect, fail, disconnect, reboot, etc.

5. Last time! What are the layers of the internet, and the order in which we structure them?

• * Application

• * Transport

• * IP

• * Link

6. What does the browser do when you click a Hypertext Link from your current web page to another web page?

• It does a Request-Response Cycle

7. What does port 23 do? (Check for common ports)

• Telnet (Login)

8. What does port 80 do?

• HTTP

9. RFCs are: (Check all that apply)

• Requests For Comment

• Issued by the Internet Engineering Task Force (IETF)

• The standards defining protocols on the Internet

10. Which of the following is most like a TCP/IP port number:

• Telephone extension

11. What is a protocol?

• A set of rules that govern how different components of the Internet interact with each other

Internet History, Technology, and Security - Week 7

Technology: Transport Control Protocol (TCP)

1. What part of data transfer does TCP solve, and what part does IP solve?

• The reliability of data transmissions, and the actual movement of the data

  2. What is window size in regards packet transfer?

• The amount of data that can be sent before receiving an acknowledgement

3.What was the problem that Van Jacobson experienced and worked to solve?

• Extremely slow transmission of data when two fast internal networks were connected via a slow network.

4. The storage of unacknowledged data is whose responsibility?

• The transport layer of the sending computer

5. How did Van Jacobson change TCP so that it would work properly?

• He changed the sending computer to start sending data slowly and speed up as the data was acknowledged

6.What do we learn from the four layer TCP about about how to solve complex problems?

• Break things up into smaller pieces, and allow many different people and organizations to tackle each piece indvidually.

7. If you listened closely to the Bob Metcalfe video, he mentioned that Ethernet was designed after the early ARPANET had been designed and knowing how ARPANET would work allowed him to greatly simplify the design of Ethernet. Which layer is most likely the layer that let him keep Ethernet simple? (Video)

• TCP – Because he knew that lost packets would be re-transmitted by a higher layer

8.When we talk of the protocols that move data over the Internet, we talk of TCP/IP. Which of the following is FALSE about TCP/IP:

• IP makes use of TCP as its underlying transport mechanism

9. In TCP, when does a sending system know it is safe to discard packets after it has sent them?

• After it has received an acknowledgement from the receiving system.

10. If you wanted to register the domain dr-chuck.go.com – who would you contact?

• The owner of go.com

11. Which of the following is a domain name?

• www.umich.edu