The Role Of Cryptography In Network Security Computer Science Essay

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Network security is concerned with the protection of network resources against alteration, destruction and unauthorized use, cryptography and encryption are most critical components of network security. In my assignment, as a network security manager, I will try to research "explore the performance of various cryptographic schemes and evaluate web security and the security of wireless network system".

Networks take all kind of sensitive data and security play a vital role of any wireless network system. Security certify level of data integrity and data confidentiality as maintain wired network, without accurately implement security measures and wireless network adapter come within range of the network adapter. Security is high lack, laziness, and lack of knowledge and employee are not aware of these things, especially in small organisation and home, every organisation need to aware and training for employees time to time.

Cryptology has two components, kryptos and logos. Cryptographic methods to certify the safety and security of communication and main goal is user authentication, data authentication such as integrity and authentication, non-repudiation of origin, and confidentiality and it has two functions encryption and decryption.

In my research, as a network security manager, I will analyze cryptography, web security, and security of wireless network system to implement the network security strategies for the organisation in future.

1. Explore and explain different types of cryptography and assess the role of cryptography in network security.

Cryptography has different methods for taking clear, readable data, and converts into unreadable data of secure communication and also transforms it back. Cryptography is also used to authenticate identify of message source and certify integrity of it. Cipher send message and use secret code. "The cipher scrambles the message so that it cannot be understood by anyone other than the sender and receiver. Only the receiver who has the secret code can decipher the original message, thus ensuring confidentiality." (Citrix-system, 2010)

Type of cryptography

Following three common types of cryptography as below:

Secret key cryptography is identified as symmetric key cryptography. Both sender and receiver know same secret code described the key and messages are encrypted by the sender and use key, decrypted by the receiver. It use single key for both encryption and decryption. This method works healthy "if you are communicating with only a limited number of people, but it becomes impractical to exchange secret keys with large numbers of people". Secret key cryptography use is such as data encryption standard, advance encryption standard, Cast-128/256, international data encryption algorithm, and rivest ciphers etc. (Citrix-system, 2010)

Public key cryptography is called asymmetric encryption and use couple of keys one for encryption and another for decryption. Key work in pairs of coordination public and private keys. Public key can freely distributed the private key. If senders and receivers don't have to communicate keys openly, they can give private key to communication confidentially. Public key cryptography use for key exchange and digital signatures such as RSA, digital signature algorithm, public-key cryptography standard etc.

Hash functions use a mathematical transformation to permanently encrypt information. It also called message digests and one way encryption. Hash function use to provide a digital fingerprint of file contents and it is commonly employed by many operating system to encrypt passwords and it provide measure of the integrity of a file. It is also use message digest, secure hash algorithm, RIPEMD etc. (Kessler, G,2010)

The role of cryptography

Many feature combine to throw network security to the top issues in the organisation and face IS professional daily. Nowadays business operation decentralization and correspondence growth of computer network is the number one driver of concern about the network security. As far as security concern, many organisation networks are accidently waiting to occur, such accident will occur is impossible to predict but security breaches will occur. When organisation network security chooses is 100% involve cryptography technology. The following five basic uses of cryptography in network security solution are:

Confidentiality - Cryptography gives confidentiality through changing or hiding a message and protects confidential data from unauthorized access and use cryptographic key techniques to critically protect data;

Access control - Only authorized users (login & password) can access to protect confidential data etc. Access would be possible for those individual that had access to the correct cryptographic keys; (Mitchell, M, 1995)

Integrity - Cryptographic tools give integrity verify that permit a recipient to authenticate that message transformed and cannot prevent a message from being transformed but effective to identify either planned and unplanned change of the message;

Authentication is the ability to verify who sent a message. It done through the control key because those with access to the key are able to encrypt a message. Cryptographic function use different methods to certify that message is not changed or altered. These hash functions, digital signatures and message authentication codes.

2. Explore encryption for network security.

Encryption for network security

Encryption is the most effective method to reduce data loss or theft to encrypt the data on the network security. Encryption is a process of network security to apply crypto services at the network transfer layer on top of the data link level and under the application level. Network encryption other name network layer or network level encryption. The network transfer layers are layers 2 and 4 of the open systems interconnections (OSI) is the reference model, "the layers responsible for connectivity and routing between two end points. Using the existing network services and application software, network encryption is invisible to the end user and operates independently of any other encryption processes used. Data is encrypted only while in transit, existing as plaintext on the originating and receiving hosts".

Encryption for network security execute through internet protocol security and set of open internet engineering task force (IETF) standard and apply in combination and build structure for confidential communication over IP networks. Internet protocol security works through the network architecture and encrypted packets show to be the same to unencrypted packets and rout through any IP network easily. Network encryption product and services provide several companies such as Cisco, Oracle etc. (Search security, 2010)

Figure - 1 Network Encrypted

3. Critically review the key and password management in terms of network system security.

The key management

Information become essential assets and protects it and availability is vital for business success. Encryption is the technology for doing so and become significant part of network system security. Encryption key is very helpful to secure data and information. There are two types of key public and private key use to secure the information and network. These key used in cryptographic system as below:

Public Key - it was invented in 1976 and refer to cypher architecture type and apply two key pairs is encrypt and decrypt. It can use to encrypt message and corresponding private key to decrypt it. Public key encryption believe extremely secure because it does not need secret shared key among the sender and receiver. It is helpful for keeping private emails and stored on mail servers for many years. It programs such as PGP has digital signature ability built message sent can digitally signed.

Private Key - it also called secret key and encryption/decryption key to exchange secret messages and shared by the communicators so that each can encrypt and decrypt messages. Public key uses with private key together. (Search-security 2010)

Password management

Password is the most important aspect to login into the system and the network. Organisation should allow only authorised users to access to the network and every user access individual login and passwords to enter the network, its result increase the security aspects. There are following necessary things to secure password in the network system as below:

Long Password - every user need to long password because short password can very quickly compromised and analyse the permutation based on the password length;

Change password anytime - employee should change password regularly, nobody assume easily and helpful for security breaches of the network;

Avoid utilize similar password - don't use the same password for different accounts because it would naive for administrator to think and employee should use different password for safety and security for network system;

Necessity to changing password regularly - employees also gradually more access their work accounts from remote location, user need to educate/awareness on the required of altering the password frequently. (Storts, J, 2010)

4. Compare symmetric and asymmetric encryption systems and their vulnerability to attack.

Symmetric encryption systems and their vulnerability

Symmetric encryption system use same secret key is used to encrypt and decrypt information and transform between two keys. Secret key concern to information to transform the content because both can use encrypts and decrypts traffic. Symmetric encryption system has two types are:

Stream ciphers - it is bits of information one at a time and operates on 1 bit of data at a time. It is faster and smaller to implement and have an important security gap. Certain types of attacks may cause the information to be revealed;

Block ciphers - it is encrypts information by breaking it down into blocks and encrypt data in each block and this data is fixed sized commonly 64 bit and mostly use in triple DES and AES. (Encryptionanddecryption, 2010)

Symmetric encryption algorithms including Des, 3DES, AES, and RC4 etc. 3DES and AES are normally used in IP sec and other types of VPNs. RC4 is used on wireless networks and used by WEP and WPA for encryption. "Symmetric encryption algorithms can be extremely fast, and their relatively low complexity allows for easy implementation in hardware. However, they require that all hosts participating in the encryption have already been configured with the secret key through some external means". (Stretch, J, 2010)

Symmetric Encryption Vulnerabilities are:

To break symmetric encryption system through brute force and cryptanalysis;

Figure-2 Symmetric encryption system

Weak password can break symmetric encryption systems;

Password always keep in mind or make a backup copy of the password;

Exchange secret keys in secure manner and stored properly. (Encryptionanddecryption, 2010)

To leaking and spying out password.


Asymmetric encryption systems and their vulnerability

Asymmetric encryption system use two keys one for encryption use for public, anyone can encrypt a message and another for decryption use for private and only receiver can decrypt a message, normally set up a key pair within a network and involve in six main elements are:

Plaintext - Text message applied in algorithm;

Encryption algorithm - it performs mathematical operation to conduct substitutions and transform to the plaintext;

Public and Private keys - the keys pair where one use for encryption and other decryption;

Ciphertext produce encrypt message by applying algorithm to plaintext message through using key;

Decryption Algorithm generates ciphertext and match key to produce the plaintext. (Encryptionanddecryption, 2010)

Most common asymmetric encryption is RSA and if compare with symmetric encryption it is much slower but its capability to establish secure channel over a non-secure medium such as internet. "This is accomplished by the exchange of public keys, which can only be used to encrypt data. The complementary private key, which is never shared, is used to decrypt." (Stretch, J, 2010) asymmetric_encryption.png

Asymmetric Encryption Vulnerabilities are:

Figure-3 Asymmetric encryption systemPublic key can be distributed freely;

It is computing intensive;

It process very slowly;

Weak password can easily steal;

Weak encryption to break this system;

Crash digital signature;

Security breach at the time of key exchange.

5. Explain and critically assess web security and critically list down different type web security tools and technologies.

Web security

Web is very vital role in our daily life such as online searching, surfing, customers, vendors, co-staffs, email, etc but need to be web security and identity theft protection. Web security has many problems like spam, viruses, security breaches & theft etc. This problem with web security is the part of network of attack computers and servers send out spam messages without knowing it and email / passwords produce and re-sale to competitor.

In my research, security expert says that "shows you how to "do something in five minutes" and conveniently neglect to mention the security implications of their advice. If it sounds too easy to be true, it probably is. A perfect example of this is PHP solutions that use a file for data storage and ask you to make it writable to the world. This is easy to implement, but it means that any spammer can write to this file." (Heilmann, 2010)

Web security has many risk and attacks such as IP address identify the computer, Fixed IP address is larger security risk, share network, staff unaware security leak in the network setting, SQL injection attacks, exploits browsers and websites, remote file inclusion (RFI), phishing etc. (Heilmann, 2010)

Web Security Tools and Technologies

The following list down of different type of web security tools and technologies as below:

Spike Proxy

It is a professional grade tool for looking for application level vulnerabilities in web application and cover SQL injection and cross-site-scripting;

Power fuzzer

It capable of spidering website and identifying inputs and common web vulnerabilities such as XSS, SQL injection and support https. Written in python;

Sec point penetrator

It network security tools based, penetration testing appliance or web based service give vulnerability scan pen testing and can change IP address to scan and report;

Net sparker

It allows users to exploit the identified vulnerabilities and see real impact of the problem. It capable false positive free, handling of websites that rely on AJAX and JavaScript;


It uses multiple techniques such as conditional errors injection, blind injection based on integers, strings/statements, MS-SQL verbose error message and identify database version and gather information

Gama Sec

It is automated online website vulnerability assessment delivers test to web servers, web based application and web-interfaced system and support HTTP authentication schemes, HTTP protocol, BASIC etc;

NIkto Scanner

Open source web server scanner and perform complete tests against web servers for multiple items, dangerous files, CGIs, and problems of the server;

Perimeter check

it analyze external network devices such as servers, websites, firewalls, routers and security vulnerabilities and also lead to interrupted service, data theft, system destruction and help immediately remedy security problem. (Hower, R, 2010)


6. Identify vulnerabilities and mis-configurations in wireless networks.

Vulnerability and mis-configuration describe as some event that exposes organisation and network security has ability to work efficiently its required confidentiality level and protects lack of the systems.

Wireless networks vulnerabilities

Some of the following common wireless networks vulnerabilities as below:

No set physical boundaries - wireless access points can lose signals, due to doors, walls, floors, and insulation etc;

Untrained users setting up unauthorized networks and workstation - untrained users "who either are uninformed and therefore unaware of security measures that must be taken when deploying wireless, or whose desire to have wireless is so strong that it completely overshadows the rules set by the organization to ensure that systems are secure". (Lane, H, 2005)

Rogue access points - this attack consist of connecting illegal access point on the network;

Lack of monitoring - every organisation has some loopholes in monitoring but intrusion detection tools can use continuously monitor to secure the network system;

MAC address filtering - it is unique number assigned and wireless LANs allows access point to connect to network. Filtering can result in security breach as user change MAC address, it result identity theft;

Insufficient encryption standards - weak encryption standard say that users will not enable it and harmful to wireless LAN as weak encryption;

Easy to eavesdrop - wireless use airwaves to listen easy on network traffic or connect to network and it results the data is encrypted with strong encryption. If WEP encryption use, hackers can some attempt to decrypt the information;

Unsecure holes in network - hacker can enter wireless LAN by circumventing firewalls and allow other to come, as a result confidential data lost or may compromise on the network;

Denial-of-service attacks - external causes based is Denial-of-service attacks and make network unproductive and forcefully user to disconnect continually disrupting operation in the organisation such as jamming (jam a radio network), rush access (overload network with malicious connection), spoofed de-authentication frames etc. (Lane, H, 2005)

Wireless network mis-configuration

Mis-matched software and hardware - it is problem arises for network infrastructure that is vulnerable to wide range of attacks. Sometime function work properly but awfully mis-configured;

Service Set ID (SSID) - SSID is a configurable identification mechanism to enables a client to communicate with the correct base-station. Configured properly with SSID otherwise attacker can exploit the SSID in attempt to access base station and change SSID password and change 802.11 security settings for authentication. (Spam-laws, 2009)

7. Demonstrate how to keep wireless network system safe.

Nowadays, wireless network become more common called Wi-Fi /802.11 and allow computer to connect to another without cables and using computer easier and more convenient than ever before with fast internet connection and wireless router and surf internet, data transfer, print documents, email, download information etc but unhappily, it also make easy for outsider/hacker to do the same. Organisation should following points to keep wireless network system safe and secure as below:

Keep-out undesirable wireless guests - wireless network restrict access through encryption is easy through which encoding or scrambling information to receive and send, only those can access with right password or encryption key and restrict wireless network to normal office hours. Some encryption protect wireless network such as wired equivalent protection (WEP), Wi-Fi protected access (WPA), WPA2 etc;

Choose strong password - in my research, I found some basic guideline when create a wireless network password is

Password should be longer (20 characters) it takes someone to figure it out;

Use mixture lowercase and uppercase letters;

Insert numbers in between letters;

Change password every 3 months;

Write password down and keep in safe (in case of forget).

Use the firewall - it is front security and secures network, computers and data from snooping eyes; (Bryan, S, 2010)

Don't show the name of the network (SSID);

Change default SSID, don't use name to identify the organisation;

Use MAC filtering because each network card is unique code known MAC address and access points to restrict access to assured;

Switch on and use built-in encryption to prevent eavesdrop;

Restrict user ability (network administrators) to setup quick and dirty wireless network, even temporarily. One rogue access point can undo all the good work you do on the others;

Certify all security measures are in place, it result defence against intruders; (Microsoft, 2010)

Turn off the wireless network when it isn't use;

Hide/keep safe place confidential files/data.


I conclude that security of wireless network system play key role in every organisation and also implement all network security strategies for the organisation in present and future and secure network resources against alteration, destruction, and unauthorized use. Cryptography tools and web security tools are also very helpful to secure the network system and protect IT assets, confidential data and information.


I recommend some of the important points as below:

Better education and stronger security implementation;

Wireless network awareness and training for employees timely;

Update wireless network security timely;

Certify to secure wireless access point with a strong password;

When it need implement WEP authentication method;

Make sure all users have proper key or password configured on their system;

Make sure all service provide to users are protected by end to end encryption;

Use SSID, MAC address filtering allows to configure wireless APs.