An attack is any malicious or accidental disruption of the confidentiality, integrity or availability of information and network resources. Attacks can come from many places: electronic, physical or human. Electronic attacks can come from the external network (Internet) or the internal network (Intranet); physical attacks can take the form of sabotage or theft of materials and equipment, and human attacks most often take the form of social engineering. Some of the attacks identified and evaluated in this paper are: spoofing, replay attacks, relay drop access attacks, and source and repudiation attacks. Identity theft occurs when attackers attempt to impersonate someone else, usually a genuine user. The phenomenon of web spoofing, or creating deceptive websites that accurately represent real sites in order to extract personal financial data from unwary web visitors, is a common form of online scam that helps identify financial fraud and credit and threatens to undermine consumer confidence in the Internet. purchases and banking operations. The FBI calls identity theft "the most widespread and troubling new scam on the Internet, contributing to the increase in identity theft, credit card fraud, and other Internet fraud." . Around thirty of these scam attack sites are detected each day, although many others go undetected. Replay attacks occur when the attacker attempts to capture packets en route from one host to another and then replay them on a targeted host in an attempt to imitate a legitimate user or system. Replay attack is easy because it is not difficult to capture commands to replay. A user on a network can run a sniffer program and capture all packets that pass through the network. The replay attack looks for systems with low...... middle of paper ......es and the disadvantages of symmetric and asymmetric cryptography are: Symmetric advantages • Use password verification to prove the identity of the recipient. transferred over the link even if there is a chance that the information could be intercepted. No keys are transmitted with the information, the likelihood of the data being decrypted is unlikely • Secure • Quick and easy to implement Symmetric Disadvantages • Unable to provide digital signatures which cannot be repudiated • Share keys • Cause a lot of damage if compromised• Have difficulty with key transportAsymmetric advantages• Scalable and does not require much administration• Easy for the user to use• Can provide digital signatures that can be repudiatedSymmetric disadvantages• slower due a longer key length • complexity of the encryption algorithm used