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Caesar Cipher

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Security & Encryption

Caesar Cipher

Encode and decode text using the Caesar cipher with custom shift.

Workspace

Run the tool here

Browser utility

Input

Shift

Output

Run the workspace to see the response here.

How to use

Enter the text and the shift value.
Choose encode or decode.
Copy the result and keep the shift key.

About this tool

Shift letters by a chosen amount to encode or decode a Caesar cipher.

Caesar Cipher is part of the TmpMailer Security & Encryption set — free browser utilities that open instantly, need no account, and pair well with a temporary-email workflow when you just need a quick result.

Common use cases

Teaching classical cryptography.
Creating a simple puzzle.
Decoding a historical-style message.

Common questions

How many possible keys are there?

Twenty-five useful shifts. That is small enough to try every key by hand or script.

Does it handle lowercase and uppercase?

Yes, case is preserved. Non-letters are left alone.

Is it secure?

No. Frequency analysis breaks it quickly. Use modern encryption for anything sensitive.

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