Graduate Assignment

Due: August 3rd

Only Masters students in ECE750 Section 001 need to do this assignment.

Overview

This assignment asks you to watch a keynote video about cryptography use by activitsts in South Africa during apartheid. You need to watch the video, answer the following questions about it, and upload the answers to Crowdmark.

Video

In the below talk, Seny Kamara describes how the African National Congress (ANC) develped an imporved secure communication system during apartheid using tape-recorded DTMF tones and public payphones.

Crypto for the People, Invited talk at Crypto 2020 by Seny Kamara only the portion of the video between 20:40 - 35:00 needs to be watched.

Questions

Answer the following questions and upload them to Crowdmark:

  1. Briefly describe the threat model that motivated the creation of the Vula system described in the video. Include the capabilities of the attacker. Also discuss the limitations of the defenders. (4 points)

  2. Assume the South African government learns that ANC members are using public payphones but does not know which ones. Propose one realistic attack against the system. Evaluate whether the attack would likely succeed. (4 points)

  3. The system is purposely asynchronous. What security advantage exists to making it asynchronous? Think about the threat model described above. (4 points)

  4. Suppose the ANC had access to modern smartphones and WhatsApp. Which aspects of the original threat model would still exist and which would change? Discuss at least two threats that become easier and two that become harder. (5 points)

  5. The encryption scheme used pseudo random number generators based on seed values. These seeds were the keys. They took the keys from books. How is this approach similar and different from one-time-pads? (5 points)

  6. Identify one design decision in the Vula system that you think was particularly strong and one that you think was a weakness. Include timestamps for where both are described in the video. Justify both judgments using concepts from this course and evidence from the talk. (11 points)

  7. Kamara argues that the ANC’s challenge was not simply an encryption problem. Drawing on the talk and any external resources you choose to consult (include full citations), explain why existing cryptographic methods in the mid-80’s were not sufficient for the ANC’s needs. Identify at least three constraints faced by ANC operatives and discuss how those constraints affected the design of secure communications. In your view, which aspects of the Vula system relied on cryptography and which aspects relied on operational security (OPSEC)? Provide examples from the talk with timestamps to support your argument. (12 points)

  8. Select one course activity that you believe best connects to the Vula system. The connection does not need to involve cryptography directly. Answer all three parts: (10 points)

    • (a) What was the primary security lesson taught by the activity?
    • (b) How did that lesson appear in the Vula system?
    • (c) Either:
      • One way the ANC successfully applied that lesson
      • One way following that lesson would have been difficult in the ANC’s operating environment.

  9. Describe something you learned from the video (include timestamp) that you personally found to be surprising or that changed your understanding of cryptography. Explain why you found it surprising or why it changed your understanding of cryptography. (5 points)

Answer formatting

Answer length Most answers should be approximately 100-300 words. The lower-point questions are expected to be on the shorter end of that range and the higher-point answers on the longer end. Longer answers are acceptable if additional detail is necessary.

Timestamps Answers should cite video timestamps whenever discussing specific events or system properties described in the talk.

Citations If external sources are being referenced, then a full citation must be provided directly after the answer OR in a references section at the end of the document. The citation should use a common referencing format like MLA or APA, and it should be used consistently, we will take marks off for some citations being in say MLA and others in APA.

Submission

Submission is done on Crowdmark labeled “Graduate Assignment”. This submission option is only visible to students enrolled in ECE750.

Grading

Each question above has a set number of points associated with it. Higher grades will be awarded for analysis, evaluation, and synthesis of ideas rather than simple summaries of the talk. The question portion totals 60 points.

The following criteria will also be considered when grading:

  • Engagement With Source Material

    • Appropriate use of timestamps.
    • Accurate description of events and system properties from the talk.
    • Use of evidence from the talk to support claims. Optionally use of external references to support additional fact statements.

  • Overall Coherence and Professional Writing

    • Arguments are internally consistent.
    • Responses do not contradict one another.
    • Writing is clear and concise.
    • Citations are present where required.

Final Exam

The material covered in this assignment may appear on the final exam and does count towards the 30% of final exam points that are linked to assignments. Students should ensure that submitted answers accurately reflect their own understanding of the topic. Instructors and TAs may draw from concepts discussed in the assignment when designing final-exam questions.