Cryptography: Encryption and Hashing

Learning Objectives Define plaintext, ciphertext, encryption, and decryption. Explain the role of a 'key' in cryptography. Differentiate between encryption (two-way) and hashing (one-way). Manually encrypt a short message using a simple Caesar cipher. Manually decrypt a short message using a simple Caesar cipher and a given key. Describe why hashing is used for storing passwords. Identify at least two real-world examples of where encryption is used. Have you ever sent a secret note to a friend? 🤫 How did you make sure no one else could read it? In this lesson, we'll explore the digital version of secret codes, called cryptography. You will learn how encryption keeps your messages private and how hashing protects your passwords, which are super important sk...

TermDefinitionExample CryptographyThe science of writing and solving secret codes to protect information.Using a secret decoder ring to send a message that only your friend with the same ring can read. PlaintextThe original, readable message before it's been scrambled.The simple message 'hello'. CiphertextThe scrambled, unreadable message after it has been encrypted.If you encrypt 'hello' with a simple code, it might become 'khoor'. EncryptionThe process of turning plaintext into ciphertext using a secret code or 'key'.Using a rule like 'shift every letter forward by 3 places' to turn 'cat' into 'fdw'. DecryptionThe process of turning ciphertext back into plaintext using the correct 'key'.Using the rule &...

Caesar Cipher Algorithm Ciphertext Letter = Plaintext Letter + Key This is a simple encryption method. To encrypt, you pick a number as your key and shift each letter of your message forward that many places in the alphabet. To decrypt, you shift the letters backward by the same key. The One-Way Hashing Rule hash_value = hash_function(data) Hashing is like putting something in a blender. You can put 'apple' in and get a smoothie, but you can never turn the smoothie back into a perfect 'apple'. This is used for passwords because even if a hacker steals the hashed passwords, they can't easily figure out the original ones.