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Tool Factory

Cryptography & Ciphers

RC4 Cipher Processor

Apply RC4 with explicit key, format, and algorithm settings. Enter the data and key material, choose the parameters, then review the result.

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Apply RC4 with explicit key, format, and algorithm settings. Enter the data and key material, choose the parameters, then review the result.

This tool runs open-source code from CyberChef by GCHQ (Apache License 2.0). See open-source credits.

RC4 Cipher Processor uses RC4 stream transformation to process the supplied input. The operation returns RC4 ciphertext in the selected output format using the supplied passphrase.

The operation returns RC4 ciphertext in the selected output format using the supplied passphrase. Processing runs in the browser for this catalog category, so the result depends on the supplied bytes and settings. Processing runs in the browser.

RC4 changes bytes with a passphrase; it does not provide modern confidentiality or message integrity.

Instructions

  1. Provide text or data for this tool.
  2. Enter a public test passphrase and short message. This applies to RC4 Cipher Processor.
  3. Set Passphrase encoding, input format, and output format explicitly. This applies to RC4 Cipher Processor.
  4. Use the same passphrase and formats to reverse a test value. This applies to RC4 Cipher Processor.

Example

Input: Input "Test message"; Passphrase "public-test" in UTF8; Input format UTF8; Output format Hex.

Settings: RC4 Cipher Processor: Passphrase: public-test with UTF8 encoding. Input format: UTF8. Output format: Hex.

Result: The operation returns RC4 ciphertext in the selected output format using the supplied passphrase. Processing runs in the browser for this catalog category, so the result depends on the supplied bytes and settings.

Limits

  • RC4 Cipher Processor: RC4 is a legacy stream cipher and does not provide authenticated encryption.
  • RC4 Cipher Processor: Changing passphrase encoding changes the derived RC4 key stream.
  • RC4 Cipher Processor: This operation has no IV, mode, or padding control; do not invent one for interoperability.

Questions

What should I enter for RC4?

Enter the source data and select its actual Input format. Supply the matching Passphrase and choose a byte-safe Output format for ciphertext. Literal hexadecimal characters differ from bytes decoded as Hex.

Why does RC4 fail to match another implementation?

The operation does not add an independent authentication tag. Treat it as legacy compatibility or analysis.

Can RC4 recover an unknown password?

This operation applies the passphrase you provide; it does not search passwords. RC4 output alone does not establish that the passphrase is correct. Confirm a known sample and the surrounding protocol conventions.