Intrusion Detection System (IDS), as its name suggests, is used to detect network anomalies. It is nothing but a combination of software and hardware used to network and host monitoring. If you are a network administrator, and you have the habit of regularly checking your server log, workstation login details, and/or firewall access logs. Then you […]
Screened Subnet Architecture refers to setup a firewall (or two firewalls) in a way that there is a separate subnet dedicated for network di-militarized zone (DMZ). The traffic comes from external Internet can only get to the DMZ whereas internal users can access the DMZ only before their traffic going to reach Internet. Bastion Hosts […]
Firewall is a perimeter security device. A perimeter security device is only good at protecting the internal network from external attack. That means if an intrusion originates from internal network, then firewall cannot deal with it. Statistics shows that most of the network attacks of an organization comes from internal employee and hence most likely […]
Firewall cannot operate properly without careful configuration. It is actually a device that help realize your company (or home)’s Internet Access Policy. Who decides the Internet Access Policy? The information owner! Many people mistaken this to be done by the company’s system administrator. It is wrong. The administrator’s role is to help implementing the firewall […]
What can be improved so that the the susceptibility to frequency analysis attack problems of alphabetic subsitution methods like Caesar Cipher and Monalphabetic Substituion can be removed? We can use a different set of encryption mapping in the order of each alphabet encryption. Suppose we have the sentence again ATTACK STARTS ON SEVEN TONIGHT We […]
To improve Caesar Cipher Encryption, we can assign each alphabet with another one in an non-sequential manner. For example A can be mapped to D while B can be mapped to R, and so are the rest being mapped to a different alphabet. Recall that Caesar Cipher has a key space of 25, Monoalphabetic Substitution […]
One information that is truly important when conducting Cryptographic Attack, it is: the nature of the plaintext. Is it a sentence of a particular language? or is it of some software code? If we know the fundamental nature of the plaintext, then our code breaking job could be a bit easier. If it is of […]
In cryptographic study, we know the simpliest way to conceal the information is by ‘substitution’. You replace the original word/alphabet by another word/alphabetic ‘systematically’. The word ‘systemtically’ have to be in place because you need a way to decrypt the concealed message. In Latin language system, we use a alphabet to replace another one sequentially […]
