Revision

Revision

1. Cyber attacks

   • Forms of malware
     • Ransomware
       • Encrypts data and demands money for its decryption. Usually targets big businesses and hospitals who they know will pay.
     • Botnets
       • A network of computers under the control of a hacker
     • Keylogger
       • A form of malware that traces all of your keystrokes and sends them to a hacker.
   • Phishing
     • Phishing is a very common type of cyber attack that sends a link to a a fake website in an attempt to make the victim enter there password and other important information which will then be sent to them.

2. Cyber defences.

   • Anti virus software
     • This is the most common form of defence against cyber attacks as it scans your computer for known viruses and removes them
       • Very important to keep your anti virus software up to date with the latest malware defintions as it will be unable to protect your computer from new viruses. Without updating the system it is almost useless.
   • White hat hackers
     • These hackers are employed by companies to hack into there defences to see if there are any areas of there defences that are weak and easily accessible so that the company can make that area stronger and make sure black hat hackers cannot exploit there weaknesses.
   • Grey hat hackers
     • Grey hat hackers do the exact same job as a white hat hacker but they are not employed by a company to do it. They hack and exploit their weaknesses and then call the company anonomously advising them to employ a white hat hacker to check out there system.
   • Black hat hackers
     • This kind of hacker exploits weaknesses but instead of reporting to the company they hack it for their benefit using a malware technique like ransomware or botnet.

3. Encryption

   • Altering important data making it only readable by the intended recipient ad nobody else.
   • Any encryption starts with the plaintext which is the not encrypted data readable for everyone. Then the plaintext will be changed to ciphertext which is the data in its encrypted form. The only way to read the ciphertext is with a key that changes the data to its original form.
   • Caesar cipher: This is an example of a cipher as it changes each letter in the alphabet by shifting it a certain number of places to the left or right.
     • Simple to crack using the brute force method as there are only 26 possible shifts for the encrypted text.
   • Substitution cipher: This cipher is also relatively simple with each letter being replaced by another random letter.
     • A far bit harder to crack meaning the brute force method wouldn't work as there are just too many possible solutions. For this type of cipher you would use a statistical attack which is where you look at each word for example if 'a' was replaced with 'k' the is there were any solo letters you would know a is most commonly alone so 'k' would most likely be 'a'. It is about knowing the most common letter for example is 'e' so the letter that pops up most is likeliest to be 'e'.