In this assignment, you are required to complete the following questions: 1. Ali
ID: 3582732 • Letter: I
Question
In this assignment, you are required to complete the following questions:
1. Alice can read file X, can append to file Y, and can write to file Z. Bob can append to file X, can write to file Y, and cannot access file Z. Design the access control matrix M that specifies the described set of access rights for subjects Alice and Bob to objects file X, file Y and file Z.
2. Write the set of access control lists and the set of capability list for the previous question (Q1)
3. What is port scanning and how is it typically launched?
4. What is the difference between symmetric and asymmetric encryption?
5. What is a process, and how is it managed in Windows 7?
Explanation / Answer
1 ans:
Alice read file X
Alice append x to y
Alice write to z
Bob append to x
Bob write to Y
Bob cannot have access to z
From the above access control matrix is:
Alice
Bob
File X
Read
Append
File Y
Append
write
File z
Write
---No access
2 ans:
Access control list for the given three files:
File x- {(Alice,{read}),(bob,{append})}
File y – {(Alice,{append}),(bob,{write})}
File z - {(Alice,{write})}
Capabilities set is:
Capablities of Alice: {(filex.sys(read)), (filey.sys{append)),(filez.sys(write))}
Bob: {(filex.sys(append)), (filey.sys(write))}
3 ans:
a port scn is all about to learn about networks of computer through an attempt
It is a good approach for crackers and as well a port scan consists of sending
messages to each port one at a time.
There are differenttypes of port scans
UDP
Sweep
Strobe
Vanilla
In this approach ports are nothing like liitele doors of our systems.
Most of the data packets tranfer throgh that only. Packets transfer in two protocols TCP, UDP.
port scans are launched to see which ports are in open status and with listening service
on the system.
4 ans:
Symmetric encryption:
Symmetric encryption is depends on security and how well the sender and receiver
protects the encrypteion key.
Symmetric encryptionis used one secret key that has is shared among reciever and sender
Assymetric encryption:
It is more secured than the symmetric encryption. it relies on digital certificates.
It uses public and private key to decrypt and encrypt messages during communication.
5 ANS:
Process: A process specified for a particular task. A process is an instance of program
running inside the system. A process may be having child process or sub process.
Process calls the new process or child processes.
Processes can exchange information or synchronize their operation through several methods of interprocess communication
In windows there is task manager is handled of all the tasks which are running
inside the system.
Alice
Bob
File X
Read
Append
File Y
Append
write
File z
Write
---No access