NazoRaku - Cipher Puzzles
Solve it. Understand ciphers.
Free · In‑App Purchases · Designed for iPad. Not verified for macOS.
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. Work out the key from a clue and enter it, spot letters with frequency analysis, reverse-look up a grid - relive that "aha" moment of decryption again and again.
[ 9 ciphers, 57 puzzles ]
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 - 17 puzzles
- XOR (6, free) - Exclusive OR; XOR with the key to recover the text
- Public-Key, simplified RSA (4, Modern Cipher Pack) - Work out the number locked with the public key
- Hash Function (4, Modern Cipher Pack) - Feel one-wayness; find an input that collides to the same output
- Block Cipher, AES-style (3, Modern Cipher Pack) - Step through add-key, substitute, and permute, one move at a time
[ Features ]
- Explanation right after you solve - history, real-world usage, weaknesses, and the bridge to modern tech
- Staged hints - the first level is free; reveal more step by step 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 (including your daily solving streak)
- iPhone and iPad
- Japanese and English (UI, puzzle text, and hints; follows the device language)
- Ciphertext shown in an easy-to-read 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.
[ Pricing ]
Free to play. All 40 classic-cipher puzzles and the 6 XOR puzzles are free.
In-app purchases: hint tickets (1 or a 10-pack), Remove Ads, the Modern Cipher Pack (unlocks public-key, hash, and block ciphers), and an all-in-one Premium (remove ads + all stages + unlimited hints). Non-consumable purchases can be restored from "Restore" in Settings / Store (hint tickets are consumable and cannot be restored).
[ Ads ]
To keep the app free, ads are shown at the bottom of screens such as Home and the stage list. No ads are shown on the screen where you solve puzzles.
On first launch, the app asks whether ads tailored to your interests (personalized ads) may be shown. You can change this anytime from "Ad Settings" in Settings / Store.
Ratings & Reviews
- This app hasn’t received enough ratings or reviews to display an overview.
- Fixed an issue where the app closed after choosing "Show personalized ads" in the ad settings.
- Fixed input fields where tapping sometimes did not bring up the keyboard, and added a Close button to the keyboard.
- Number fields can now be cleared completely and re-entered, and oversized numbers that are typed or pasted are kept at the field's maximum.
- Fixed I/J answer matching in Polybius puzzles and the results shown in explanations after clearing a stage.
The developer, Fuji Bit Inc., indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Used to Track You
The following data may be used to track you across apps and websites owned by other companies:
- Identifiers
- Usage Data
Data Not Linked to You
The following data may be collected but it is not linked to your identity:
- Identifiers
- Usage Data
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- Fuji Bit Inc.
- Size
- 7 MB
- Category
- Puzzle
- Compatibility
Requires iOS 17.0 or later.
- iPhone
Requires iOS 17.0 or later. - iPad
Requires iPadOS 17.0 or later. - Mac
Requires macOS 14.0 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 1.0 or later.
- iPhone
- Languages
- English and Japanese
- Age Rating
4+
- 4+
- Contains
Advertising
- In-App Purchases
Yes
- Premium (All-in-One) $14.99
- Modern Cipher Pack $5.99
- Remove Ads $3.99
- 10 Hint Tickets $5.99
- 1 Hint Ticket $0.99
- Copyright
- © 2026 Fuji Bit