AES Encrypt / Decrypt — Free Online Tool
Encrypt any text using AES-256-GCM — the same algorithm used in HTTPS and Signal. The passphrase is stretched into a 256-bit key via PBKDF2-SHA256 (100,000 iterations) with a random salt. Output is a self-contained base64url string. The same tool decrypts it given the correct passphrase.
100% client-side. No uploads. Your data never leaves your browser.
How to use AES Encrypt / Decrypt
- Select Encrypt or Decrypt mode.
- Enter your message or ciphertext.
- Enter your passphrase (keep it safe — you need it to decrypt).
- Click the button and copy or save the output.
Frequently Asked Questions
Is this real encryption?
Yes. AES-256-GCM is the gold standard for symmetric encryption, used in HTTPS, WhatsApp, and Signal. The key is derived from your passphrase via PBKDF2 with 100,000 iterations.
Can I decrypt without the passphrase?
No. Without the correct passphrase, decryption is computationally infeasible. If you lose the passphrase, the data is unrecoverable.
Why does the same text encrypt differently each time?
AES-GCM uses a random initialization vector (IV) and random salt each time. This is correct and expected — it prevents pattern analysis. Only the passphrase matters for decryption.
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