NazoRaku - Cipher Puzzles

Ciphers, solved by playing. Crack classic and modern ciphers from Caesar to RSA and hashing—work out the key, use frequency analysis, then learn how each works.

A puzzle game where you UNDERSTAND ciphers by solving them - not by reading about them. From the Caesar cipher to RSA and hashing, crack classic and modern ciphers one stage at a time, and the way each cipher works clicks into place. Slide to find the key, spot letters with frequency analysis, reverse-lookup a grid - relive that "aha" moment of decryption again and again.

[ Classic ciphers - free, 40 puzzles ]

• Caesar (10) - Shift letters; work out the shift from the crib and enter it
• Vigenere (10) - Polyalphabetic with a keyword; guess the key
• Substitution (8) - One-to-one swap; crack it with frequency analysis
• Transposition (6) - See through the reordering
• Polybius Square (6) - Letters to numbers via a 5x5 grid; reverse-look up

[ Modern ciphers ]

• XOR (6) - Exclusive OR; XOR with the key to recover the text (free)
• Public-Key (RSA, simplified) - Lock with the public key, find the message
• Hash Function - Feel one-wayness; find an input that collides to the same output
• Block Cipher (AES-style) - Step through add-key, substitute, and permute rounds

[ Features ]

• Explanation right after you solve - history, real-world usage, weaknesses, and the bridge to modern tech
• Staged hints - a free recap first, then gradual reveals when stuck (keeps the "I solved it" feeling)
• No ads at all while you are solving a puzzle - designed to preserve focus
• Achievement badges and stats for collection
• Universal app for iPhone and iPad
• Japanese and English (UI, puzzle text, and hints; follows the device language)
• Ciphertext shown beautifully in a monospaced font

[ Who is this for ]

• Anyone who loves puzzles and riddles
• Students and engineers curious about cryptography and security
• People who want quick brain-training in spare moments

[ Part of the Raku Series ] The third information-systems title of the Raku Series. Knowledge from ARURAKU (algorithms) and DATARAKU (data structures) pays off in NazoRaku's decryption - hashing and modular exponentiation tie ciphers back to the fundamentals.

[ Note on pricing ] Free to play. All classic-cipher stages and the modern-cipher intro are free. Hints, ad removal, the Modern Cipher Pack, and an all-in-one Premium are available as in-app purchases. No ads are ever shown while you are solving a puzzle.