How Encriptar/Desencriptar AES Works
The Advanced Encryption Standard (AES) is the global benchmark for electronic data encryption. Also known as Rijndael, it is a "Symmetric-Key" block cipher, meaning the same secret key is used for both encrypting and decrypting the data. Defined in FIPS PUB 197, AES is trusted by governments, banks, and intelligence agencies to protect the world's most sensitive information.
The AES engine operates through a series of mathematical "Rounds" (10, 12, or 14 depending on the key length):
- Block Creation: Data is divided into 128-bit blocks (16 bytes), organized into a 4x4 grid (State).
- Key Expansion: The original secret key is expanded into several "Round Keys" using the Rijndael Key Schedule.
- SubBytes Transformation: Each byte in the block is replaced by another using a pre-defined lookup table (S-box). This provides non-linearity and protects against mathematical attacks.
- ShiftRows and MixColumns: The rows of the grid are shifted horizontally, and the columns are mathematically mixed. This ensures that every bit of the output depends on multiple bits of the input (diffusion).
- AddRoundKey: A Round Key is combined with the State using a Bitwise XOR operation.
- Ciphertext Output: After the final round, the resulting "Ciphertext" is typically outputted in Base64 or Hex format for safe storage.
The History of AES and Joan Daemen
In the late 1990s, the U.S. National Institute of Standards and Technology (NIST) announced a competition to replace the aging DES (Data Encryption Standard). Out of fifteen international candidates, the "Rijndael" cipher was selected as the winner.
It was designed by two Belgian cryptographers, Joan Daemen and Vincent Rijmen. Their design was praised for its mathematical elegance, its resistance to all known attacks, and its exceptional performance on everything from supercomputers to Smart Cards. NIST officially adopted it as AES in 2001, and it remains the standard for the Modern Internet.
Technical Comparison: AES vs. RSA vs. ChaCha20
Choosing the right encryption algorithm is a matter of speed, key length, and implementation context.
| Feature | AES (Symmetric) | RSA (Asymmetric) | ChaCha20 (Stream) |
|---|---|---|---|
| Key Pairs | One Shared Key | Public & Private Keys | One Shared Key |
| Speed | Extremely Fast | Very Slow | Extremely Fast |
| Security Level | High (Quantum Resistant) | Moderate (Vulnerable) | High |
| Common Use | Hard Drives / Large Files | Key Exchange / HTTPS | Mobile CPUs / VPNs |
| Block Size | 128-bit Fixed | Variable | Not Applicable |
By using a dedicated AES tool, you can protect your data using the same standards used by the U.S. Federal Government for classified information.
Security Considerations: Keys and IVs
AES is mathematically unbreakable, but it can be defeated by poor implementation:
- Key Strength: Always use AES-256 for long-term security. While AES-128 is faster, AES-256 provides a significant margin of safety against future Quantum Computing threats.
- Initialization Vector (IV): You should never encrypt two different messages with the same key and the same IV. Doing so creates patterns that an attacker can exploit. Our tool generates a random, cryptographically secure IV for every session.
- Encryption Modes: Avoid the "Electronic Codebook" (ECB) mode, as it preserves patterns. We use the more advanced Cipher Block Chaining (CBC) or Galois/Counter Mode (GCM) for authenticated encryption.
- Client-Side Privacy: To maintain the absolute Privacy of your data, all encryption and decryption happens locally in your browser. Your secret keys and private files never leave your machine.