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AES Decrypt (AES-256-GCM)

Paste the Base64 or hex ciphertext, enter the passphrase, and recover the original text.

Processed locally in your browser

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The same passphrase used for encryption. The iteration count is read from the data.

0 chars · 0 lines
The result will appear here.

What is AES Decrypt (AES-256-GCM)?

This is the counterpart of AES Encrypt. It reads the container ("DTAE" magic, version, PBKDF2 iteration count, salt, IV, ciphertext and GCM tag), derives the same 256-bit key from your passphrase with PBKDF2-HMAC-SHA-256 and decrypts with AES-GCM. The iteration count is read from the data, so you do not have to remember it.

AES-GCM is authenticated: if the passphrase is wrong, or even a single bit of the data was changed or truncated, decryption fails with a clear message instead of returning garbage. Base64 and hex inputs are detected automatically. It only opens data produced by the AES Encrypt tool, not arbitrary AES files from other programs.

How does it work?

  1. Paste the encrypted text (Base64 or hex) exactly as the AES Encrypt tool gave it.
  2. Enter the same passphrase that was used to encrypt.
  3. Click Decrypt. The original text appears, or you get a message saying the passphrase is wrong or the data was modified.

Common use cases

  • Reading a note you encrypted earlier and stored in a file or message.
  • Verifying that a ciphertext round-trips before relying on it.
  • Testing how a modified ciphertext is rejected by authenticated encryption.
  • Decrypting a secret that a colleague sent you along with a separately shared passphrase.

Examples

Try this input in the tool above:

Input
RFRBRQEAAYagg8kbNuFJhcNXIfU0mnvMX9qteGoCmVFwe87LngpSSsNcICkl9HcmutSYXtAKhxO2auxKRXp40Eov3IPVZB0h8VsPhhTMrI3i9XZMmKyO
Output
Meet me at the usual place at 9pm.

Privacy

AES Decrypt (AES-256-GCM) runs entirely in your browser. The text or files you provide are processed on your device and are not uploaded, logged or stored on our servers.

Limitations

It cannot recover data without the correct passphrase, and it does not attempt to guess passphrases. It only reads the tool’s own format. For high-stakes data prefer audited software; keep passphrases in a password manager.

Frequently asked questions

Why does it say wrong passphrase or corrupted data?

AES-GCM cannot tell the two cases apart: a wrong key or any changed byte makes the authentication tag fail. Check the passphrase (case, spaces) and that the whole text was pasted.

Can it decrypt files from OpenSSL, GPG or other tools?

No. It reads only the "DTAE" container format created by AES Encrypt on this site, documented in the AES Encrypt page.

Do I need to know the iteration count?

No. It is stored in the header of the encrypted data and used automatically. It is authenticated too, so tampering with it is detected.

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