2.3 Encryption

Plain Text & Ciphertext

• Plain text: original data sent (no encoding)
• Ciphertext: plaintext that has been encoded

State the purpose of encrypting data

• Data becomes scrambled/unreadable.
• If intercepted it will not be understood

Symmetric Encryption

• Data is encrypted and decrypted using the same key/algorithm
• Encryption algorithm is used
• Data before encryption is known as plain text
• Data after encryption is known as cipher text
• Key is sent to receiver (to allow data to be decrypted)

Explain how data is encrypted using symmetric encryption

• Data is encrypted and decrypted using the same key
• Plain text is encrypted into cipher text
• Data is encrypted using an algorithm…
• …that uses a key
• The key can be generated using an algorithm
• The key is transmitted to the receiver

Asymmetric Encryption

• Asymmetric encryption was developed to overcome the security problems associated with symmetric encryption
• Uses a public key and a private key
• Public key is available to everyone
• Private key only known by the computer user
• Both keys are needed to encrypt and decrypt data

State differences and similarities between Symmetric and Asymmetric

Differences

• Symmetric has a shared key…
• …to encrypt and decrypt
• Both the sender and receiver know the key
• Asymmetric has different keys (public + private)
• …public to encrypt the data and private to decrypt
• …anyone can know the public key but only those intended know the private key

Similarities

• They both use a key
• They both scramble data
• They both turn plain text to cipher text

SSL (Secure Sockets Layer)

State how SSL secures the data for transmission

• It encrypts it
• Uses digital certificates