AES Encryption
Encrypt and decrypt text with AES-256 algorithm
La contraseña se usa para generar la clave AES-256
Sobre el cifrado AES-256
- • AES-256-GCM: Algoritmo de cifrado simétrico de grado militar
- • PBKDF2: Derivación de clave con 100,000 iteraciones
- • Salt aleatorio: Cada cifrado genera un salt único
- • IV único: Vector de inicialización diferente cada vez
Free Online AES-256 Encryption - Secure Text Encryption
What is AES-256 encryption and why is it so secure?
AES (Advanced Encryption Standard) is the symmetric cipher adopted by the United States government and used worldwide to protect classified information. AES-256 uses 256-bit keys, which means 2^256 possible keys, a number with 77 digits. With current technology a brute-force attack would take billions of years. It is the industry standard for protecting banking data, military communications, medical records and any sensitive data that demands maximum security.
How do GCM mode and PBKDF2 key derivation work?
This tool uses AES-256-GCM (Galois/Counter Mode), which provides both confidentiality through encryption and authentication through message integrity. GCM detects whether anyone has tampered with the ciphertext, protecting you against manipulation attacks. The password you type is turned into a cryptographic key with PBKDF2 (Password-Based Key Derivation Function 2) using 100,000 iterations and a unique random salt, which makes dictionary attacks impractical even with relatively simple passwords.
Why is local processing crucial for security?
Your text and your password NEVER leave your browser. All encryption and decryption happens locally through the browser Web Crypto API, a native and audited cryptographic implementation. We send nothing to any server, store nothing, and cannot see your information. You can verify that yourself by disconnecting from the internet and confirming that the tool keeps working perfectly. This is the safest way to encrypt sensitive information online.
If you work with this tool, you will probably also find these useful Base64 Encoder, RSA Key Generator, HMAC Generator, Bcrypt Generator.
Frequently asked questions
Can I decrypt my data if I forget the password?
No, it is cryptographically impossible. AES-256 is designed precisely so that without the correct password the data is completely unrecoverable. There is no backdoor, no password recovery and no alternative way in. That is why you must keep your password somewhere safe, such as a password manager. This is a security feature rather than a flaw: it guarantees that nobody, including us, can reach your encrypted data.
Is this tool safe for highly sensitive information?
Yes, for most use cases. AES-256-GCM is the same algorithm used by banks, governments and the military. For nation-state level threats or genuinely life-or-death information, however, consider using your own verified encryption software, keeping your operating system patched, checking that you are on the correct URL to rule out phishing, and choosing long unique passwords. The weakest link is almost always the chosen password, not the algorithm.
Why is the encrypted text longer than the original?
The output carries more than the ciphertext alone: a 16-byte random salt for secure key derivation, a 12-byte initialisation vector (IV) required by GCM, the encrypted data itself, and a 16-byte authentication tag used to verify integrity. All of that is encoded in Base64, which adds roughly another 33%. This overhead is the price of genuinely secure encryption with authentication built in.
What is the difference between AES and RSA for encrypting data?
AES is symmetric encryption: it uses the same key to encrypt and decrypt, it is very fast, and it handles large volumes of data comfortably. RSA is asymmetric: it uses a key pair, public to encrypt and private to decrypt, it is far slower, and it is limited to small amounts of data. In practice the two are combined: RSA encrypts a random AES key and AES encrypts the actual payload. This tool uses plain AES because it fits encrypting text with a password both parties already share.