1. Entity Relationship Diagram problem:

• Prepare ERD by using draw.io. Hand-drawn diagrams will not be accepted as valid submissions.
• The ERD must have all the maximum and minimum cardinalities identified. State any assumptions if necessary.
• The ERD must be converted to a list of tables (schema) by using the 4 conversion rules discussed in class (gradings for this part are based on whether you have used all the applicable conversion rules, and used them correctly)

Draw an E-R diagram for the following situation: Shi- nyShoesFor All (SSFA) is a small shoe repair shop located in a suburban town in the Boston area. SSFA repairs shoes, bags, wallets, luggage, and other similar items. Its customers are individuals and small businesses. The store wants to track the categories to which a customer belongs. SSFA also needs each customer's name and phone number. A job at SSFA is initiated when a customer brings an item or a set of items to be repaired to the shop. At that time, an SSFA employee evaluates the condition of the items to be repaired and gives a separate estimate of the repair cost for each item. The employee also estimates the completion date for the entire job. Each of the items to be repaired will be classified into one of many item types (such as shoes, luggage, etc.); it should be possible and easy to create new item types even before any item is assigned to type and to remember previous item types when no item in the database is currently of that type. At the time when a repair job is completed, the system should allow the completion date to be recorded as well as the date when the order is picked up. If a customer has comments regarding the job, it should be possible to capture them in the system.

2. TCP/IP problem :

Network access control is very important for information security. The Internet uses mostly TCP/IP to deliver data/messages between individuals and businesses. What is TCP/IP? How does TCP guarantee the delivery of data/messages through the Internet? Please draw a diagram to show your answer. You need to make explanations of what you have drawn and show your understanding of the mechanism. Please note that if you do not draw the diagram, you will not receive points for the explanation.

3. Encryption

Nowadays, many business transactions occur digitally using the Internet. Businesses must obtain the same level of assurance about the enforceability of a digital transaction that a signed document provides for a paper-based transaction. The digital signature is used to accomplish this by using hashing and asymmetric encryption.

Please use a diagram to explain the mechanism of asymmetric encryption through the use of public key and private key. Your diagram and explanation are required.Please note that if you do not draw the diagram, you will not receive points for the explanation.

Also, in Digital Signature, the private key is used to encrypt the documents. Please explain why.