Question 1 (5 pts) One-time pad (OTP) encryption is provably secure. It would be expected that an unbreak- able encryption method would be highly desirable yet it is not widely used. Describe what makes OTP hard to use in practice. Question 2 (5 pts) Comparing secret-key and public-key encryption, what is the main advantage that the latter offers over the former? Question 3 (10 pts) The definition of a Shift Cipher can be expressed as follows: Def. Let x, y, k 226 with the encryption operation as ek(x) = x + k mod 26 and the decryption operation as dk(y) = y - k mod 26. Given the provided letter encoding, what would be the encoding of the plaintext word ATTACK after applying a shift cipher with a k=17? ABCDEFGHIJKLM 0 1 2 3 4 5 6 7 8 9 10 11 12 NOPQRSTUVWXYZ 13 14 15 16 17 18 19 20 21 22 23 24 25 Question 4 (10 pts) Assume a hash function H(m) which is collision resistant. This particular function maps a message of arbitrary bit length into an n-bit hash value. Can we assume that for all messages m, m' with m # m', we have H(m) + H(m')? You must explain your answer to receive credit. (Hint: see textbook section about Secure Hash Functions.) Question 5 Develop a single program using any programming language (e.g. Java, Python, C++, etc.) that: a. (15 pts) Encrypts and decrypts a message using the Cesar's Cipher. The user encrypting the message is prompted to enter a message and then a key that indicates the displacement. The user decrypting the message is prompted to enter the encrypted message and the key. b. (10 pts) Decrypts and displays all (26) possible solutions. Requirements. 1. Your may not collaborate with others. 2. You may not use existing code that you find on the internet or any other resource (even if you cite it) 3. Unfortunately, your instructor is not permitted to provide any programming assistance. This assignment serves as an accreditation evaluation requirement for the program to assess stu- dent ability to code in the discipline. If you have passed CSIT 512 and/or you have otherwise fulfilled the Foundation requirement for programming, you should be able to partially or fully complete this assignment. If not, we may have to revisit the need to (re-)take CSIT 512. 4. If you are unable to complete this question due to lack of time rather than inability to code, please make sure that you indicate: Not Complete (lack of time) in the Question 1-4 submission document under Question 5 or, Partially Complete (lack of time) in the README file along with the description of what has been done. A. Submission Requirements (Questions 1-4 1. Assignment must be delivered in one document that has your full name, email and semester/year. Filename: CYBR555-lastname_fname assignment_01 2. Format: 1-inch margin all around, 12 point font, page numbers. 3. You must indicate the question number your are answering using a heading and a number (e.g. Question 1) for the question and the enumeration of each sub-question. 4. Questions answered must be listed in order. If a question is skipped, the question heading and number must still appear in the document. 5. The submission and all its elements (e.g. tables, graphs, etc) must be created electronically (not photos, scans of hand-drawn parts) unless this is conducted as an in-class exercise. 6. Failure to comply will result in a 25% point reduction. B. Submission Requirements (Question 5 You must submit in a single .zip or .tar file: 1. Your source code. 2. A README text file that describes the requirements to run the code (e.g. Java, Python, C++, etc.) and a brief description of what exactly your program does, any assumptions (and what it doesn't do related to the assignment) and a URL of an unlisted, private link to either YouTube or Vimeo of the code being executed (see next). 3. You must provide a live, video compilation and execution of a sample run of your code. Your video must be a screen capture, no cell phone or camera recording of your screen
