Rijndael Encryption/Decryption Tool
Original AES algorithm with flexible block size options
Rijndael vs AES
AES is a subset of Rijndael (fixed 128-bit block size). This tool supports the full Rijndael specification (128/192/256-bit blocks).
About Rijndael Encryption
Rijndael is a symmetric-key block cipher designed by Belgian cryptographers Joan Daemen and Vincent Rijmen. It was selected by NIST as the winner of the Advanced Encryption Standard (AES) competition, becoming the global standard for encryption. While AES is strictly defined with a fixed block size of 128 bits, the original Rijndael algorithm supports variable block sizes of 128, 192, and 256 bits, offering greater flexibility and potentially higher security margins for specific applications.
This tool provides a full implementation of the Rijndael algorithm, allowing you to experiment with configurations that go beyond the standard AES specification. By supporting 256-bit block sizes alongside 256-bit keys, Rijndael offers a theoretical security advantage against certain types of cryptanalysis compared to the 128-bit block size limit of standard AES. All encryption and decryption operations are performed entirely in your browser using JavaScript, ensuring that your sensitive data never leaves your device.
Rijndael vs AES Comparison
| Feature | Rijndael | AES |
|---|---|---|
| Block Size | 128/192/256 bits | 128 bits |
| Key Size | 128/192/256 bits | 128/192/256 bits |
| Standard | AES Original | NIST FIPS 197 |
| Flexibility | High | Medium |
Key Features
- Flexible Block Sizes: Supports 128-bit (AES standard), 192-bit, and 256-bit block sizes.
- Variable Key Lengths: Full support for 128-bit, 192-bit, and 256-bit encryption keys.
- Comprehensive Modes: Includes CBC, ECB, CFB, OFB, CTR, and RAW modes for diverse security needs.
- Client-Side Security: 100% local processing; no data is ever transmitted to a server.
Encryption Modes
- CBC: Each plaintext block is XORed with the previous ciphertext block. Requires IV, provides strong security.
- ECB: Each block encrypted independently. No IV needed, but identical plaintext produces identical ciphertext.
- CFB: Cipher Feedback mode converts block cipher to stream cipher. Requires IV.
- OFB: Output Feedback mode, similar to CFB but generates keystream independently. Requires IV.
Security Considerations
- Local Processing: Data is processed in the browser memory, preventing network interception risks.
- Strong Encryption: Uses the same mathematical foundation as the U.S. government standard AES.
- IV Management: diverse IV handling options ensure semantic security in CBC/CFB/OFB modes.
- Open Source: Transparent algorithmic implementation for verification and educational trust.
Use Cases
- Advanced Security: Using 256-bit blocks for higher collision resistance than standard AES.
- Legacy System Support: Interacting with systems implementing non-standard Rijndael parameters.
- Educational Analysis: Understanding the relationship and differences between Rijndael and AES.
- Cryptographic Testing: Validating test vectors for different block/key size combinations.
References
Frequency Asked Questions (FAQ)
What is the difference between Rijndael and AES?
AES is a subset of Rijndael. The AES standard (FIPS 197) strictly defines the block size as 128 bits, while allowing key sizes of 128, 192, or 256 bits. Rijndael, the original algorithm, was designed to support block sizes of 128, 192, and 256 bits (and others in the spec) independently of the key size. This tool allows you to use those non-standard block sizes.
Is Rijndael encryption secure?
Yes, it is extremely secure. Rijndael was selected as the Advanced Encryption Standard (AES) after a rigorous 5-year analysis by the world's leading cryptographers. It is approved by the NSA for top-secret information (when using standard AES parameters) and is the de facto global standard for data encryption.
When should I use the 256-bit block size?
You should use the 256-bit block size if you need to interface with a specific system that requires it, or if you desire a higher margin of security against birthday attacks (collision attacks) than the 128-bit block size provides. However, for maximum compatibility with standard software and libraries, the 128-bit block size (AES mode) is recommended.
What is RAW mode?
RAW mode processes a single block of data without any padding or chaining mode. It is primarily useful for educational purposes, debugging the core algorithm, or verifying test vectors. It is not recommended for encrypting general data files or messages as it cannot handle data longer than the block size securely.
Is my data sent to your server?
No. This tool is built with a privacy-first architecture. All cryptographic operations (encryption and decryption) are executed locally in your web browser using JavaScript. Your keys, IVs, and plaintexts are never transmitted over the internet or stored on our servers.
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