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, Page 1 of 8 School of Science COSC2536/2537 Security in Computing and Information Technology Assignment 1 Assessment Type: Individual assignment; no group work. Submit online via Canvas → Assignments → Assignment 1. Marks awarded for meeting requirements as closely as possible. Clarifications/updates may be made via announcements/relevant discussion forums. Due date: Week 5, Friday the 23rd Aug 2019 11:59pm Deadlines will not be advanced, but they may be extended. Please check Canvas→Syllabus or via Canvas → Assignments → Assignment 1 for the most up to date information. As this is a major assignment in which you demonstrate your understanding, a university standard late penalty of 10% of full mark (i.e. 1.5 marks) per each working day applies for up to 5 working days late, unless special consideration has been granted. Weighting: 15 marks (Contributes 15% of the total grade) 1. Overview The objective of Assignment 1 is evaluating your knowledge on the topics covered in Lecture 1-4. Topics include Basic Cryptographic Techniques, and Public-Key Cryptography (RSA, ElGamal and Paillier cryptosystems). Assignment 1 will focus on developing your abilities in application of knowledge, critical analysis and decision making. Assignment 1 contains several problems related to the topics mentioned above. You are required to prepare the solutions and upload them as a single PDF or Word document in CANVAS. In this assignment, there are 6 (six) questions in total. The first question Q1 is on cryptanalysis. The term Cryptanalysis is used to breach cryptographic security systems and gains access to the contents of encrypted messages, even if the cryptographic key is unknown. Therefore, you are expected to apply cryptanalysis in order to obtain plaintext from the given ciphertext in Q1. The second question Q2 is about the application of hash algorithm. Q2 has two parts. In the first part, you are expected to perform a forward search attack for a given protocol that uses hash algorithm for providing security. In the second part, you have to discuss a modified version of the given protocol where the forward search attack would not work. The third question Q3 is related to RSA Encryption algorithm. In this question, you are expected to demonstrate your understanding of the RSA Encryption algorithm. Values of required parameters are provided including the plaintext or message M and you should demonstrate the key generation, encryption and decryption processes with detail computations and brief explanations. Marks will be deducted if you fail to show the detailed computation correctly, skip the computation steps, or do not provide explanations. The fourth question Q4 is related to breaking the RSA Encryption algorithm. In this question, you are expected to determine the plaintext M from the ciphertext C without knowing the RSA private-key. Public-key parameters and ciphertext are provided to you. You should demonstrate the detailed steps with explanations about how the RSA encryption algorithm can be broken. Marks will be deducted if you fail to show the detailed computation correctly, skip the computation steps, or do not provide explanations. The fifth question Q5 is related to ElGamal Encryption algorithm. In this question, you are expected to demonstrate your understanding of the ElGamal Encryption algorithm. Values of required parameters are provided including the , Page 2 of 8 plaintext or message M and you should demonstrate the key generation, encryption and decryption processes with detailed computations and brief explanations. Marks will be deducted if you fail to show the detail computation correctly, skip the computation steps, or do not provide explanations. The final question Q6 is related to Paillier Encryption algorithm. In this question, you are expected to demonstrate your understanding of the RSA Encryption algorithm. Values of required parameters are provided including the plaintext or message M and you should demonstrate the key generation, encryption and decryption processes with detail computations and brief explanations. Marks will be deducted if you fail to show the detailed computation correctly, skip the computation steps, or do not provide explanations. Develop this assignment in an iterative fashion (as opposed to completing it in one sitting). You should be able to start preparing your answers immediately after the Lecture-1 (in Week-1). At the end of each week starting from Week-1 to Week-4, you should be able to solve at least one question. If there are questions, you must ask via the relevant Canvas discussion forums in a general manner. Overall, you must follow the following special instructions: • You must use the values provided in the questions. • Hand-written answers are not allowed and will not be assessed. Compose your answers using any word processing software (e.g. MS Word). • You are required to show all of the steps and intermediate results for each question. • Please DO NOT provide codes as an answer. Only codes will not be assessed. • Upload your solution as a single PDF or Word document in CANVAS. 2. Assessment Criteria This assessment will determine your ability to: • Follow requirements provided in this document and in the lessons. • Independently solve a problem by using cryptography and cryptanalysis concepts taught over the first four weeks of the course. • Meeting deadlines. 3. Learning Outcomes This assessment is relevant to the following Learning Outcomes: • understand the fundamentals of cryptographic techniques. • analyse the security limitations of early cryptographic techniques. • learn the fundamentals of cryptanalysis. • learn how hash algorithms and public-key cryptography scheme works. • understand the applications of hash algorithms and public-key cryptography scheme. • develop libraries of public-key cryptographic techniques using any programming language of your choice. • use public-key cryptographic techniques in small and large scale applications. 4. Assessment details Please ensure that you have read Section 1 to 3 of this document before going further. Assessment details (i.e. question Q1 to Q6) are provided in the next page. , Page 3 of 8 Q1. Cryptanalysis (Marks: 4.5) (a) [Cryptanalysis on Simple Substituion Cipher] (Marks 1) Show step-by-step process to find the plaintext and the key for the following ciphertext using the concept of simple substitution cipher ‘shift by n’ as discussed in Lecture-1: Ciphertext: NZXMTYLETZYD Find the plaintext using shift by n as discussed in Lecture-1 and tutorial-1. (b) [Cryptanalysis on Double Transposition Cipher] (Marks 1.5) Decrypt the following ciphertext using the double transposition cipher (as discussed in the Lecture-1 and Tute-1) using a matrix of 7 rows and 8 columns. Ciphertext: NAGEIDVTATLNIITYNDFAOICENHANICTICPRTEYHTPTOSMRIAAYPORHGI Hint: The first two words in the plaintext are “THE” and “CRYPTOGRAPHY”. (c) [Cryptanalysis on Substitution Cipher] (Marks 2) Assume that the following ciphertext has been produced using a substitution cipher. Please note that it may not be a simple ‘shift by n’ substitution. The ciphertext is as follows: MDUNPWV UF IYR PEUQUIV BK PT UTLUNULSPQ BD JDBSM IB FRWQSLR IYRZFRQNRF, BD UTKBDZPIUBT PEBSI IYRZFRQNRF, PTL IYRDREV RHMDRFF IYRZFRQNRF FRQRWIUNRQV. IYR EBSTLPDURF PTL WBTIRTI BK AYPI UF WBTFULRDRL MDUNPIR LUKKRD PZBTJ WSQISDRF PTL UTLUNULSPQF. AYRT FBZRIYUTJ UF MDUNPIR IB P MRDFBT, UI SFSPQQV ZRPTF IYPI FBZRIYUTJ UF UTYRDRTIQV FMRWUPQ BD FRTFUIUNR IB IYRZ. IYR LBZPUT BK MDUNPWV MPDIUPQQV BNRDQPMF AUIY FRWSDUIV, AYUWY WPT UTWQSLR IYR WBTWRMIF BK PMMDBMDUPIR SFR, PF ARQQ PF MDBIRWIUBT BK UTKBDZPIUBT. MDUNPWV ZPV PQFB IPCR IYR KBDZ BK EBLUQV UTIRJDUIV. IYR DUJYI TBI IB ER FSEXRWIRL IB STFPTWIUBTRL UTNPFUBTF BK MDUNPWV EV IYR JBNRDTZRTI, WBDMBDPIUBTF BD UTLUNULSPQF UF MPDI BK ZPTV WBSTIDURF' MDUNPWV QPAF, PTL UT FBZR WPFRF, WBTFIUISIUBTF. Find the plaintext by frequency analysis technique as discussed in Lecture-1 and tutorial-1. Q2. Application of Hash Algorithm (Marks: 2)