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Computer Security Exam March 4th, 2016 First name: ________________________ Last name: ________________________ Matricola: ________________________ Signature: ________________________ Homeworks? [ ] (Y) [ ] (N) Instructions ● The exam is composed of 6 pages. ● Just as a cross check, tell us whether you have completed the homeworks, by putting an "X" mark appropriately. ● The exam is "closed books". Please put away in a non­suspicious place (i.e. not below the desk) any note, book, or similar. You will be expelled if, at any time, if you do not follow this rule. ● You are not allowed to communicate with other students, and you will be expelled from the exam if you do. ● Shut down and store electronic devices. They will be subject to inspection if found and you may be expelled if you are found using one. ● Please answer within the allowed space. Schemes are good, short answers are recommended. ● You can write in pen or pencil, any color, but ​avoid writing in red​. ● No extra paper is allowed. ● The answers ​must be written exclusively in the space provided​ below the questions. READ CAREFULLY ​ALL THE POINTS​ OF EACH QUESTION ​BEFORE​ WRITING YOUR ​ANSWER WITH PROPOSED SOLUTION 1 of 6 Question 1 (5 points) Consider the dual signature used in SET. 1. (2 points) Explain which (a) ​properties it guarantees​ in a transaction and (b) briefly ​how it works​. It guarantees that the minimal amount of information about a commercial transaction is disclosed to the parties: the merchant is only informed about the successful payment (without knowing any payment details, e.g., credit card number), whereas the payment gateway is only informed about the payment details (without knowing the purchased goods). It is created by hashing the payment information (PI) and order information…