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RC4 Encrypt / Decrypt

RC4 Encrypt / Decrypt. Local browser processing.

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RC4All encoding tools ↗

Enter a raw hexadecimal key. A blank IV generates a fresh one in a JSON envelope; use the same mode to decrypt.

key: 5–256 bytes / no IV

How to use

  1. Enter your data and parameters, or load the example.
  2. Choose the operation and confirm the input format.
  3. Run the tool, then copy or download the result.

Example

UTF-8 ⇄ Base64

Details and limitations

Everything runs in your browser; text, files and keys are not uploaded.

Input is limited to 100,000 characters per field. Cancel stops the worker and discards the pending result.

Demo keys and passwords are public examples. Generate your own key before using real data.

Compatibility algorithms such as DES, RC4, MD2, MD4, SHA-1 and Type 7 are retained for existing systems; choose a modern algorithm for new designs.

CBC, ECB and stream ciphers do not authenticate data. A readable decryption does not prove integrity. AES-GCM verifies its tag; never reuse an IV with the same key.

FAQ

Are my keys or files uploaded?

No. Calculation happens locally in a Web Worker. Clearing or leaving the page discards its working state.

Format references

Tool page updated: