Storing Transmitting Data

Storing Transmitting Data

1. Firewall

   • They can be hardware or software and stop unauthorised access to our computers from hackers and viruses.
     • They act as a filter for incoming and outgoing traffic by checking to see if the data meets specific requirements.
       • So they block unacceptable data and let acceptable data in
         • Firewalls can be software installed on the pc or hardware which comes as a router.

2. Proxy Server as a Firewall

   • Use Case 1 - The proxy server sits infront of your webserver controlling access to the webserver.
     • This basically can protect a webservers from hackers by managing and checking the data directed to webservers by users
       • it can direct invalid traffic away from the webserver
         • Basically, what it does is check all traffic requests to webservers and examines them.
           • If they are valid, they get through and if they are not valid they are declined.
             • They can also block certain IP addresses such as no Russians please, help prevent hacking of a webserver, can be used to prevent DDoS (Distributed Denial of Service)
   • Use Case 2 : The proxy server in this case acts as the gateway to the internet for an organisations users.
     • Proxy Server act as middlemen
       • You make the request to the proxy server and it is the proxy server that makes the request for a webpage on your behalf. You remain anonymous.
         • The actual process is split into 2 parts:
           • - The proxy server intercepts all the packages hiding the true address of the client (anonymous).
           • - The proxy server has a cache of websites so once your request has been validated it can send you the page from the cache so this is fast as no need to reconnect

3. Encryption

   • Using an algorithm and a key to convert message data into a form that is not understandable without the key to decrypt the text.
     • Why would you do this?
       • • Store information securely
         • • Transmit messages so that only the sender and legitimate receiver can read them
   • Key Terms
     • • Plain Text – message data before it is encrypted
       • cipher Text – Message data after it has been encrypted
         • • Encryption - Using an algorithm and a key to convert message data into a form that is not understandable without the key to decrypt the text
           • • Decryption - Using an algorithm and a key to convert encrypted message data into its plain text equivalent
   • Symmetric vs Asymmetric Encryption
     • Symmetric
       • • Encryption is symmetric if the cipher text (that’s the text after its been encrypted) can be decrypted by knowing the encryption algorithm and the encryption key
         • • Easy to decrypt the message with key
           • • Difficult to distribute symmetric key without being intercepted
             • The user selects a key and encrypts a file. They then give the key and the ciphertext to receiver separately. The receiver can then use the key to decrypt the file into plain text.
               • The cipher can be easy to break if the language is known for example what if the key was to replace each letter with another where the key was the sixth letter on
     • Asymmetric
       • Basically, there are 2 keys at play here and that increases security.
         • If a file is encrypted using a public key, then it can only be decrypted using the corresponding private key
           • If the file is encrypted using the private key then it can only be decrypted using the corresponding public key
             • • Also called public key encryption
               • • Both parties have 2 keys – public and private
                 • • Private key is kept secret
                   • • Encryption algorithm and public keys are freely available
                     • • A message encrypted with a public key can only be decrypted with the corresponding private key
                       • • A message encrypted with a private key can only be decrypted with the corresponding public key

4. Secure Socket Layers

   • Secure Sockets layers refer to creating secure connections across a network – for example between a web browsers and a website to allow secure transmission of data
     • • Encrypts data sent over the web/network
       • • Uses symmetric and asymmetric encryption.
         • • The key itself is encrypted
           • • Makes use of public and private keys
             • • Data is meaningless without decryption key
   • It has 2 layers
     • Handshake protocol
       • record protocol
   • Security Protocols
     • This is an updated version of SSL and it also encrypts data sent over the web/network
       • Differences to SSL
         • TLS allows for session caching, a method of resuming an existing secure connection rather than establishing a new one (quicker)
           • It is possible to extend TLS by adding new authentication methods
             • TLS separates the handshaking process from the record protocol (layer) which holds all the data.
               • Where are these services used – Online shopping payments, email, cloud based storage, VPN, video conferencing, online gaming, social networking