AP CS Principles
Interactive tools and tutorials to help you review for the AP Computer Science Principles exam.
Encryption & Decryption Tools
Symmetric-Key Encryption
Encrypt and decrypt messages using a shared password (AES). See how symmetric-key cryptography works in practice.
Try it →Public-Key Encrypt
Encrypt a message using someone's public key. Only they can decrypt it with their private key.
Try it →Public-Key Generate & Decrypt
Generate your own public/private key pair, then decrypt messages that were encrypted with your public key.
Try it →Number Systems
Number Base Converter
Convert numbers between any bases — binary, octal, decimal, hexadecimal, and beyond.
Try it →Converting Decimal to Base b
Step-by-step tutorial on how to convert from decimal (base 10) to any other base, with practice problems.
Read tutorial →Programming Practice
Classroom Activities
Encryption Mission
A spy-thriller group activity where paired teams send encrypted messages while the teacher tries to intercept them. Three escalating missions cover symmetric, asymmetric, and hybrid encryption.
View activity guide →Breakout EDU: The Great Bitcoin Bonanza
A physical escape-room review game with five cryptography puzzles, real locks, and a Satoshi Nakamoto mystery. Reviews number systems, encryption, protocols, and more.
View activity guide →