The computers on two networks need to securely communicate and they use two gateways. Each gateway stores its private and public keys as well as the public key of the other gateway. They encrypt the message on one gateway and decrypted on the other. The computers on each network do not store these keys, but they use the keys that they have stored, as in part A, to encrypt their messages before sending them to the gateways. a) Sketch how does the message look like when it leaves the computer and when it leaves the gateway. What information can be encrypted and what information should be available in unencrypted format. Why? Note: The message has a payload and a header (m = hp). The header contains sender’s and receiver’s address, while the payload contains data. Use SC for sending computer, RC for receiving computer, SG for sending gateway, RG for receiving gateway, KPu for public key, KPr for private key. For example, KPuSCN1 is the public key for sending computer on network 1. Also, {m}KPuSCN2 is message encrypted with public key of sending computer on network 2. b) Would this protocol decrease the number of public and private keys needed in part A? Explain. Show how many keys are needed to be stored per computer.

1. the program must provide following functions to extract some statistics. note that the data_list parameter specified in these functions may be the same for all functions or different for different functions—that is your choice. a skeleton file is provided on mirmir. a) open_file()prompts the user to enter a year number for the data file. the program will check whether the year is between 1990 and 2015 (both inclusive). if year number is valid, the program will try to open data file with file name ‘year.txt’, where is the year. appropriate error message should be shown if the data file cannot be opened or if the year number is invalid. this function will loop until it receives proper input and successfully opens the file. it returns a file pointer and year. i. hint: use string concatenation to construct the file name b) read_file(fp)has one parameter, a file pointer read. this function returns a list of your choosing containing data you need for other parts of this project. c) find_average(data_list) takes a list of data (of some organization of your choosing) and returns the average salary. the function does not print anything. hints: i. this is not the average of the last column of data. it is not mathematically valid to find an average by finding the average of averages—for example, in this case there are many more in the lowest category than in the highest category. ii. how many wage earners are considered in finding the average (denominator)

Your company has 1,500 desktop computers running windows 7. you want to upgrade them to windows 10. which type of microsoft license would be best suited in this situation?

4. a1. vince owns a television repair shop that is insured undera commercial package policy. the policy includes thebuilding and personal property coverage form and thecauses-of-loss broad form. the declarations page indicatesthat coverage applies to both the building and the namedinsured's business property. explain whether or not thefollowing losses would be covered under his policy.a. a fire occurs on the premises, and the building isbadly damaged.b. a burglar steals some money and securities from anunlocked safe.c. a business computer is damaged by vandals whobreak into the shop after business hours.d. a tornado touches down near the store. several tel-evision sets of customers in the shop for repair aredamaged in the storm.til