Applied Cryptography And Analysis Computer Science Essay

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I have made a scheme to secure your company's (Uob Manufacturing Company) networks system using Cryptographic protocols. This system uses strong Cryptographic algorithms to encrypt data to travel save on a network. But you have to scarify 15-20% performance because of heavy encryption and decryption done by both end users. With such a minor performance penalty, your data will save. I will use The Ronald Rivest's algorithm. I think RC5 is the strongest algorithm compare to other Ron Rivest algorithms that why they called RC5 as "fast symmetric block cipher". It is compatible to almost all hardware and software. However if you want to upgrade your hardware it also supports 64 bit processor. This report also includes the


Encryption algorithms, RC5, Uob Manufacturing Company, encryption protocol, RC2, RC4, RC5, DES, Triple DES,  TRIPLE_DES_3KEY, 128-bit RC4, DESX, 128-bit AES, 192-bit AES, and 256-bit AES.


In modern era where internet plays the main part also security comes first. Cryptography is the way or art of encryption and that is the main goal. The security in networks is very important as all valuable information travels on a network. Cryptography is used for small problem to convert into hard to understand and difficult to solve.

Cryptography allows protecting from theft or alteration, but it can also help us to do user authentication. (Kessler, 21 April 2011)

There are three main types of cryptographic schemes to full fill these goals: (Kessler, 21 April 2011)

secret key (or symmetric) cryptography

public-key (or asymmetric) cryptography

hash functions

Choosing Algorithms for Encryption:

Now a days every network related person concerning many algorithms for network security for data and valuable information. These algorithms are as follow:

DES, Triple DES, TRIPLE_DES_3KEY, RC2, RC4, RC5, 128-bit RC4, DESX, 128-bit AES, 192-bit AES, and 256-bit AES.

Not all algorithms are suitable for one situation. They are implementing with the level of complexity of the situation and level of how much security required. But there are some key points on based we can choose algorithm for encryption.

Performance: Sometimes strong encryptions slow down the CPU performance while weak encryption consumes fewer resources.

Key formation: Stronger the encryption is when longer the key has given.

Differences: Asymmetric encryptions are stronger then symmetric encryptions. As Asymmetric uses same key length but they affect the performance.

Password: Stronger the encryption is when longer the password has given.

The encryption of large data should use a symmetric key, and then its key should be encrypted by an asymmetric key. (Microsoft, 2000)

Comparison Encryption Algorithms:

Most of Algorithms are protecting valuable information. But each of these algorithms has different level of capabilities and complexities for security on a network like DES, tripleDES, AES, Blowfish, RC2, RC4 and Rijndael are most secure encryption algorithms in Cryptography.

For comparison on performance of these algorithms, I have concern the other resources. I have got some know source that have cryptography libraries in Crypto++. It is free and has all C++ class libraries. It includes all types of cryptography schemes coded and compile in MS Visual C++ .Net 2003. Table 1 shows the performance of the most commonly used algorithms.

Table 1 Comparison results using Crypto++


Megabytes(2^20 bytes) Processed

Time Taken






Rijndael (128-bit key)




Rijndael (192-bit key)




Rijndael (256-bit key)




Rijndael (128) CTR




Rijndael (128) OFB




Rijndael (128) CFB




Rijndael (128) CBC
















Choosing Network Protocol for Company's network:

As looking into the diagram, first I like chose wireless network and as we learnt from comparison I would like to use RC4 encryption method for wireless network diagram and discuss some key protocols used for encryption.

Wireless network

2.1 Wireless Access point (WAP):

Has this diagram shows it is wireless connection means it will use either WIFI connection or Bluetooth connection devices.

Considering this diagram the communication between manager laptop and wireless adaptor is done by wireless Access point and USB wireless adaptor is connecting other stations. Such as wireless Access point is connected with wired equivalent protocol. As I am using RC4 encryption algorithm for security protocols of 64 bit stream cipher.


This encryption algorithm is designed by Ron Rivest for RSA security. "It is variable key size stream with byte oriented operation". It also allows random permutation. I have used RC4 to have a secured communication via WEP (Wired Equivalent Protocol). The 64 bit RC4 key stream cipher is used in WEP, because of layer two security protocol. It can let network down

3.1 Description of Wired Equivalent Privacy:

The goal is to create private wired LAN and also Wireless LAN key that will used by WEP. The key is already shared and pre-established and the basic building blocks are encryption cyclic redundancy check (CRC) And RC4

The wired equivalent protocol can be supports up to four different base keys. This can be indentified as key 0 to 3. To develop the key we will need a selected base key of 24 bit Initialization vector (IV).

3.2 Encryption details:

Analysis of Network:

The company networks seems to be very sensitive because it has lot of department that are sharing valuable information and also sharing confidential data over a network. As I have seen there is a CNC programming workstation that need to be secure and encrypted. According to network diagram another important node is wireless access point and manager's laptop because manager has company valuable data and also some financial data that cannot be access by any unauthorized user so these terminals should be encrypted and secured.


After deep investigation for current network and company's future enhancements. I suggest that company should be applying Ron Rivest's Algorithms that is RC4 that would be the best choice as suggested by the Ron L.Rivest also because RC4 is one of the strongest algorithm and also it is compatible for all sorts of software and hardware implementations. However the company want to enhance the network hardware it will also support the latest technology easily as the encryption is concern it is the strongest security system that most of the network supervior and developers are using it.