RC4 Stream Cipher (Legacy): Encrypt and Decrypt Data
The RC4 Stream Cipher (Legacy) tool encrypts or decrypts data for compatibility with older RC4 use and for studying the algorithm. Enter a key as UTF-8, hexadecimal, or Base64, then choose Base64 or hexadecimal output. RC4 is broken and prohibited in TLS by RFC 7465, so use this browser tool for legacy data—not to protect new secrets.
The RC4 Stream Cipher (Legacy) tool lets you encrypt or decrypt data with RC4 in your browser. RC4 is a stream cipher introduced in 1987 and was once widely used in SSL/TLS and WEP. This converter is intended for working with legacy data and studying the algorithm, not for protecting new secrets.
To use it, provide the input and a key, then choose the algorithm options. The key can be entered as UTF-8, hex, or Base64, and the result can be output as Base64 or hex. You can also enter a salt if your workflow requires one. These choices let you work with different representations without changing the underlying legacy algorithm.
RC4 is now considered thoroughly broken: biases in the cipher can let attackers recover plaintext. RFC 7465 formally prohibited RC4 in TLS. Use this tool only when you need to process existing RC4 data or examine how the cipher works; do not rely on it to secure new information. For legacy tasks, the ability to select key and output encodings can help match the data you have or the format you need.
The tool runs entirely in your browser. Your input is processed on your device, and no data is sent to a server. It works offline once the page has loaded, so you can continue using it without a connection. This browser-based RC4 tool can help developers, DevOps engineers, and learners handle legacy cipher data or explore the algorithm while keeping their input local.
Step 1: Paste or drop the data you want to process. Use the tool for legacy RC4 encryption or decryption.
Step 2: Enter the key, and provide a salt if needed. The key can be represented as UTF-8, hex, or Base64.
Step 3: Choose the algorithm and available options. Select Base64 or hex for the output format.
Step 4: Run the operation and review the result. Copy the output for your legacy-data workflow or algorithm study.
Use case: Check an RC4 cipher output against a value you were given. This can help verify that your input and key produce the expected result.
Use case: Explore how RC4 behaves with a known input. Trying sample data can help you study this legacy algorithm.
Use case: Process legacy data locally instead of entering it on a third-party page that sends it to a server.
Use case: Decrypt data that still needs to be read for compatibility with an older RC4-based workflow. RC4 is broken, so this is for legacy use rather than protecting new information.
Use case: Compare the same key represented as UTF-8, hex, or Base64. The available key formats make it easier to work with different representations of legacy key data.
Use case: Choose Base64 or hex output to match the representation expected by your legacy workflow or study task.