An explanation right after you solve
Historical background, real-world use, weaknesses and how the cipher was broken, and the bridge to modern technology, while the win is still fresh.
// NazoRaku — Cipher Puzzles
Ciphers make sense
once you crack them.
A puzzle game where you don't study ciphers, you break them. From the Caesar cipher to RSA and hashing, crack classic and modern ciphers one puzzle at a time. Work out the key from a clue, spot letters with frequency analysis, look up a grid in reverse, and enjoy the moment ciphertext turns into plaintext, again and again.
$ How to play — HOW TO PLAY
One stage, one puzzle. Read the ciphertext and the clue, work out the key or the answer yourself, and tap "Decrypt". Get it right and the ciphertext lights up cyan.
- 01Pick a cipher.Five classic and four modern ciphers. Each stage unlocks when you clear the one before it.
- 02Read the clue.A crib (known plaintext) such as "the first letter of the ciphertext is H in plaintext" lets you reason out the key.
- 03Work it out and enter it.Shifts and XOR keys are entered as numbers. In Vigenère, the preview clears up as you fill in the key tiles; in substitution, you map letters in a decoding memo.
- 04Cracked, then explained.After each clear, read the cipher's history, real-world use, weaknesses, and how it leads to modern technology.
$ nazoraku crack caesar KHOOR crib K → H shift 3 plain HELLO # cracked $ nazoraku crack xor 62 6F 66 66 65 crib 0x62 → 'H' (0x48) key 0x62 ⊕ 0x48 = 0x2A plain HELLO $ nazoraku crack rsa --e 3 --n 55 --c 13 try m = 7 → 7³ mod 55 = 13 plain m = 7 # matches c
$ Ciphers — CIPHERS
From classic ciphers that shift, substitute, and rearrange, to introductions to XOR, public-key, hash, and block ciphers. Every classic stage and XOR are free.
| Type | Cipher | Puzzles | How you crack it | Access |
|---|---|---|---|---|
| Classic | Caesar cipher | 10 | Letters shifted by a fixed amount. Work out the shift from the clue and enter it | Free |
| Classic | Vigenère cipher | 10 | Polyalphabetic with a keyword. Guess the key letters and fill them in | Free |
| Classic | Substitution cipher | 8 | One-to-one letter swaps. Spot letters with frequency analysis | Free |
| Classic | Transposition cipher | 6 | Letters rearranged. See through it with a column-by-column grid | Free |
| Classic | Polybius square | 6 | Letters turned into numbers on a 5×5 grid. Look it up in reverse | Free |
| Modern | XOR cipher | 6 | Exclusive OR. Work out the one-byte key to recover the plaintext | Free |
| Modern | Public key (simplified RSA) | 4 | Find the message m whose me mod n matches the ciphertext c | Modern Cipher Pack |
| Modern | Hash function | 4 | Feel one-wayness. Find an input that gives the same output (a collision) | Modern Cipher Pack |
| Modern | Block cipher (AES-like, simplified) | 3 | Relive key addition → substitution → permutation, one step at a time | Modern Cipher Pack |
$ Features — FEATURES
Designed first and foremost around the feeling of "I solved it myself."
Staged hints
The first hint is a free recap. If you are stuck, reveal more in stages: the direction to take, then the first few letters, then nearly the answer. Never the whole thing, so it still feels like your solve.
No ads while you solve
The puzzle screen never shows ads. Banners appear only at the bottom of the home and stage screens, full-screen ads only when you close a clear result at a milestone, and hint videos only if you choose to watch.
Monospaced ciphertext
Ciphertext and decryption previews are aligned in a monospaced font. Vigenère lines the repeating key up under the ciphertext; transposition lays it out column by column.
Badges and stats
Earn a badge for each cipher you complete. Puzzles solved, total puzzles, and your daily solving streak (with your best) keep you coming back.
Free to play
Every classic stage and XOR are free. Hint tickets, Remove Ads, the Modern Cipher Pack, and the all-in-one Premium are optional in-app purchases.
$ In-app purchases — IN-APP PURCHASES
All optional. See your store for prices in your region.
hint ticketsUsed for the second hint onward (1 ticket / pack of 10)
remove adsHides all banner and full-screen ads
modern packUnlocks the public-key, hash, and block cipher stages
premiumRemove Ads + all stages + unlimited hints
$ Made for — FOR
puzzlersAnyone who loves riddles and puzzles
securityStudents and engineers curious about cryptography and security
examLearners who want to get hands-on with the crypto part of IT exams
brainAnyone after a quick brain workout in spare moments
$ Raku Series — RAKU SERIES
The third title in the Raku Series for information systems. What you learn in ARURAKU (algorithms) and DataRaku (data structures) pays off when cracking ciphers in NazoRaku. Hashing and the modular exponentiation behind public keys connect straight back to those foundations.
$ Screenshots — GALLERY
