AES Encryption
Encrypt or decrypt text with AES-256-GCM using a passphrase, instantly inside your browser.
What is AES-GCM encryption?
AES (Advanced Encryption Standard) is the industry-standard symmetric encryption algorithm. GCM (Galois/Counter Mode) is an authenticated mode that both encrypts the data and detects tampering — if the ciphertext is altered or the wrong passphrase is used, decryption fails rather than silently returning garbage. This tool encrypts text with AES-256-GCM using a passphrase you choose, and decrypts it back with the same passphrase.
GuideHow to use it
How the encryption works
Your passphrase is never used directly as the encryption key — instead, it's run through PBKDF2 with 100,000 iterations and a random 16-byte salt to derive a 256-bit AES key, which makes brute-forcing the passphrase far slower. A random 12-byte initialization vector (IV) is generated for every encryption, and the salt, IV, and ciphertext are all bundled together into a single Base64 payload so nothing extra needs to be tracked separately to decrypt it later.
Why it helpsFeatures & benefits
Why this runs entirely in your browser
Both the plaintext and passphrase are sensitive, so everything runs locally using the browser's native Web Crypto API, and nothing is ever sent to a server.
Common uses
Encrypting a sensitive note before storing or sharing it, protecting a piece of text with a shared passphrase before sending it over an insecure channel, or learning how authenticated AES encryption works.
Frequently asked questions
A few things people usually want to know before trusting the numbers.
No. It's run through PBKDF2 with a random salt and 100,000 iterations to derive a 256-bit AES key, which is much more resistant to brute-force attacks than using the passphrase directly.
AES-GCM is authenticated — if the passphrase is wrong or the payload has been altered even slightly, decryption fails outright instead of returning incorrect text.
Only if it uses the exact same format: a Base64 string containing a 16-byte salt, a 12-byte IV, and AES-256-GCM ciphertext, with the same PBKDF2 parameters (100,000 iterations, SHA-256).
The encrypted text can't be recovered. There's no backdoor or recovery mechanism — that's the point of encryption.
No. All encryption and decryption happens locally in your browser using the Web Crypto API. Nothing typed here is sent to a server, stored, or shared.