Cracking encryption (extension)

What this lesson covers

Key vocabulary

Cryptanalysis

Decoding encrypted data without having the key.

Brute force attack

Trying every possible key until the right one is found.

Key length

The number of bits in a key. An n-bit key has 2ⁿ possible keys.

Non brute force attack

Working out the key with cleverer methods than trying every key.

Frequency analysis

Using how often letters appear in ciphertext to work out the key. E is the most common letter in English.

Check your learning

• Quick check: 4 questions
• Key vocabulary test: 5 terms
• Activity 1: Key strength · 8 questions
• Activity 2: Crack the code · 6 messages
• Activity 3: Cracking encryption quiz · 8 questions