+Project Goals

- Nowadays security in network is getting more and more important. Whether sharing financial, personal, military information, people want to do it securely.Cryptography is one way to achieve the security goal. No one else can understand the encrypted message without prior information. Only people who have the information - called key - can decrypt the cipher text and then can understand it. Even though this cryptography can resolve the security problem, it also creates some drawbacks.
- The major part of the disadvantage is computational overhead. There is no perfect encryption algorithm so far. So people who want more secure system are trying to make the encryption algorithm more complex so that no one can break the system. But complex encryption algorithm takes more time to encrypt a message as the complexity of the crypto system increases. In other words, if you want to use more secure system, you have to spend more time on communication. Another problem is data overhead. During the securing procedure, depending on the algorithm that used to make it secure, it may generate some additional data. It is also an overhead in network point of view.
- In this project, by simulating encryption algorithm in SSL protocol which is the most common data encryption protocol being used in HTTP, in various network conditions, we will see how the encryption algorithm affect the network performance.

+Analysis

-Fixed bandwidth




-Those three figures show that test results for different data size with the fixed bandwidth. DES and MD5 part is linear to the data size, and RSA is constant. Encrypted data transmission time is also linear to the data size. Even though the RSA is constant, it takes only small part of total processing time, so the total processing time is almost linear to the data size. Unsecured communication is strictly dependent on the data size, so with crypto/without crypto is almost constant.

-Fixed data size

-These show that test results for different bandwidth with the fixed data size. As the bandwidth grows, transmission time decreases, and the time used for cryptography stays constant. So the time with crypto/without crypto is getting bigger.
-This simulation program shows the effect of cryptography in network. Cryptography creates considerable overhead in latency time. Even though all cryptography algorithms that used in SSL are included, the application does not simulate the actual protocol. In real SSL session, the major overhead is from handshaking protocol that includes RSA and negotiation. This test program does not consider the negotiation, so it doesn't show exactly same SSL protocol simulation. It only shows the overhead caused by computations but this can gives intuition about cryptograph effect on the network communication.






+Project report
-report.pdf

+References