AES Encrypt / Decrypt

AES-GCM encryption with a passphrase (Web Crypto).

AES Encrypt / Decrypt secures text with AES-256-GCM using a passphrase, all in your browser via the Web Crypto API. Your passphrase is run through PBKDF2 (SHA-256, 100,000 iterations) to derive the key, and the random salt and IV are packed with the ciphertext into a single Base64 string. Use it to encrypt notes, tokens, or config snippets and decrypt them back later with the same passphrase.

Common uses

  • Encrypt a sensitive note or password before storing or sharing it
  • Protect an API key or token with a passphrase you can share separately
  • Decrypt a Base64 AES-GCM string you previously generated with this tool
  • Demonstrate or test PBKDF2 + AES-GCM behavior without writing code
  • Quickly verify that a passphrase correctly decrypts a given ciphertext

FAQ

Is my data sent to a server?

No. Encryption and decryption run entirely in your browser using the Web Crypto API. Neither your text nor your passphrase is uploaded anywhere.

What algorithm and key derivation does it use?

It uses AES-256-GCM for encryption. The key is derived from your passphrase with PBKDF2 using SHA-256 and 100,000 iterations and a random 16-byte salt.

What is the format of the encrypted output?

The output is a single Base64 string containing the 16-byte salt, then the 12-byte IV, followed by the AES-GCM ciphertext and authentication tag. Decryption expects this exact layout.

Why does decryption fail?

Decryption fails if the passphrase is wrong, the Base64 input is altered or truncated, or the ciphertext was not produced by this tool. AES-GCM verifies integrity, so any tampering causes an error rather than garbled text.

Can I decrypt output from other AES tools?

Only if they use the same scheme: AES-256-GCM with PBKDF2-SHA-256 at 100,000 iterations and the salt + IV + ciphertext packed in that order as Base64. Other formats will not decrypt here.

Related tools

  • Adler-32 Checksum
  • Argon2 Hash
  • Bcrypt Hash / Verify
  • CRC32 Checksum
  • File Hash
  • Hash (SHA)
  • Hash Identifier
  • HMAC Generator