Practice Puzzles

A classic introduction to cipher solving. The Roman emperor has left you a message.

An emergency signal from the past. Can you decode this urgent message?

Someone has converted a message to numbers. What does it say?

This message seems backwards. Or is it?

The most common cipher in geocaching. Can you crack it?

Computers speak in ones and zeros. Can you understand them?

The ancient Romans left numbers for us to decode.

Remember old phone keypads? Each number has letters.

The military uses words to spell things clearly over radio.

These raised dots form a tactile message.

These numbers are in base 8, not base 10!

Someone typed on a shifted keyboard.

Isthay isway away illysay oneway!

These colors have hidden numbers.

Add up these digits repeatedly until you get one digit.

Some words equal numbers when you add up their letters.

The whole message is backwards!

This encoding uses only uppercase letters and numbers 2-7.

Rearrange these letters to form words.

Not all Caesar ciphers use shift 3.

The Freemasons used this cipher for centuries.

These numbers look suspicious. What location do they reveal?

This cipher needs a keyword. The cache title "TREASURE" might be relevant.

These numbers are computer code. What do they spell?

This encoded string ends with an equals sign. What format is it?

Someone left coordinates in hexadecimal. Decode them.

The ancient Greeks used number pairs for letters.

Prisoners communicated by tapping on walls.

Hidden in plain sight with two fonts.

Only take letters at prime positions.

Like Vigenere, but reciprocal.

Flags tell the story.

Text rearranged in columns with a keyword.

Math meets cryptography.

Read every Nth letter.

Pairs of letters, 5x5 grid with a keyword.

Use Fibonacci numbers to extract letters.

These numbers hold a modular secret.

Vigenere with a numeric key.

From the start, go 500m at bearing 045°.

Notes on a staff spell something.

A progressive shift cipher.

Book numbers hide coordinates.

The message becomes part of the key!

Read the grid in a spiral pattern.

This message has been encrypted twice. Unravel both layers.

Chemistry meets geocaching. Use atomic numbers to find the location.

The message seems innocent, but counts for something.

The Hebrew scholars used this reverse cipher. Can you solve it?

This text has been scrambled in a zigzag pattern.

Configure the machine: Rotors I-II-III, Reflector B, no plugboard.

Linear algebra encryption.

Split, mix, and combine.

Four grids, two keywords.

WWI German field cipher.

Russian spy cipher from the 19th century.

Cold War numeric cipher.

Reciprocal polyalphabetic from the Renaissance.

3D fractionating cipher.

Dynamic alphabet cipher.

Find where two bearings intersect.

First letters tell a secret story.

A compact coordinate format.

Military uses a special grid system.

Sherlock Holmes faced these stick figures.

Edgar Allan Poe's pirate cipher.

Alternating single and double letters.

Horizontal variant of Four Square.

Three ciphers in sequence.

Bruce Schneier's playing card cipher.