AES Encrypt/Decrypt — Free Online AES-256 Encryption Tool
Encrypt and decrypt text with AES-256-GCM or AES-256-CBC — uses Web Crypto API with PBKDF2 key derivation.
Frequently Asked Questions
AES-256 Encryption: The Gold Standard for Symmetric Encryption
AES (Advanced Encryption Standard) is the world's most trusted symmetric encryption algorithm. Approved by NIST in 2001 and classified for use with US government Top Secret data, AES-256 provides 256-bit security — more than enough to protect any sensitive information against brute force attacks for the foreseeable future.
This tool implements AES with two modern modes: GCM (Galois/Counter Mode) and CBC (Cipher Block Chaining). AES-GCM is recommended for new applications — it's an authenticated encryption mode that simultaneously encrypts and authenticates your data, making it impossible to tamper with ciphertext without detection. AES-CBC provides encryption without authentication and should be paired with an HMAC for integrity.
Key derivation uses PBKDF2 with 100,000 SHA-256 iterations, converting your password into a cryptographic key. A unique random salt is generated per encryption, preventing pre-computed attacks. All operations use the Web Crypto API — the browser's native cryptographic implementation — with no external libraries required.