2.3 · Lesson 1 of 3
Encryption and symmetric keys
Syllabus 2.3.1Syllabus 2.3.2
What this lesson covers
- Explain why data is encrypted before transmission
- Describe symmetric encryption
Key vocabulary
- Interception
- When data is captured by someone it wasn't meant for while it's being transmitted.
- Encryption
- Scrambling data so it's no longer in an understandable format.
- Plaintext
- The data or message before it's encrypted.
- Ciphertext
- The encrypted data or message.
- Key
- A sequence of numbers or characters used with the algorithm to encrypt or decrypt data.
- Encryption algorithm
- The set of steps used to scramble plaintext into ciphertext.
- Decryption
- Turning ciphertext back into plaintext using the key.
- Symmetric encryption
- Encryption that uses the same single key to encrypt and decrypt. Also called private key encryption.
- Caesar cipher
- A simple symmetric cipher that shifts each letter forward through the alphabet by the key.
Check your learning
- Quick check: 4 questions
- Key vocabulary test: 9 terms
- Activity 1: Caesar cipher · 8 questions
- Activity 2: Encryption quiz · 8 questions
- Activity 3: Sending a message with a symmetric key · drag and drop