Topic 1: Data, information, knowledge and processing Encryption

Learning Objectives Define encryption and describe different methods of encryption (including: symmetric, asymmetric, public key, private key)

What is data encryption? Encryption is the process of converting information into a form that is meaningless to anyone except holders of a ‘key’. Define encryption and describe different methods of encryption (including: symmetric, asymmetric, public key, private key)

What is plain text? In cryptography, plaintext is ordinary readable text before being encrypted into ‘ciphertext’ or after being decrypted Define encryption and describe different methods of encryption (including: symmetric, asymmetric, public key, private key)

Symmetric Key Encryption First, Alice needs to generate a secret ‘key’ using encryption software. The key is usually a very long, random number. Define encryption and describe different methods of encryption (including: symmetric, asymmetric, public key, private key)

Symmetric Key Encryption Alice can send Bob the encrypted text, but Bob cannot read it yet Define encryption and describe different methods of encryption (including: symmetric, asymmetric, public key, private key)

Symmetric Key Encryption Alice can send Bob the encrypted text, but Bob cannot read it yet Define encryption and describe different methods of encryption (including: symmetric, asymmetric, public key, private key)

Symmetric Key Encryption Alice must then give a copy of this key to Bob. She must make sure that nobody else can get the key (USB stick) Define encryption and describe different methods of encryption (including: symmetric, asymmetric, public key, private key)

Symmetric Key Encryption Now Bob has the key he can use special software to decrypt the message. Define encryption and describe different methods of encryption (including: symmetric, asymmetric, public key, private key)

Asymmetric Key Encryption Works exactly the same. However there are 2 possible keys: Public key is made freely available to anyone who might want to send you a message. Private key is kept secret, so that only you know it. Define encryption and describe different methods of encryption (including: symmetric, asymmetric, public key, private key)

Asymmetric Key Encryption Any message encrypted by the public key can only be decrypted by using the matching private key. Any message that is encrypted by using the private key can only be decrypted by using the matching public key. Define encryption and describe different methods of encryption (including: symmetric, asymmetric, public key, private key)

How can encryption protect data in an e-mail? It can ‘scramble’ the email, and only the intended recipient can de-scramble it. Therefore sensitive information can be locked away. Define encryption and describe different methods of encryption (including: symmetric, asymmetric, public key, private key)

How can encryption protect data on a hard disk? It can protect sensitive information contained on the disk. Bank Records Personal Information Define encryption and describe different methods of encryption (including: symmetric, asymmetric, public key, private key)

How can encryption protect data in on an HTTPS websites Any information sent by a web-browser to a web server, or the other way, can be encrypted, so that no-one can intercept the information. Define encryption and describe different methods of encryption (including: symmetric, asymmetric, public key, private key)

Exam Questions Define encryption and describe different methods of encryption (including: symmetric, asymmetric, public key, private key)