AES Encryptor
Enter text and a passphrase to get an encrypted, Base64-encoded blob back — or paste that blob and the same passphrase to recover the original text. Nothing here is ever transmitted or stored.
Overview
AES-GCM is an authenticated encryption mode: it doesn't just hide the plaintext, it also detects tampering — decrypting with the wrong passphrase or a modified ciphertext fails outright instead of silently returning garbage. This tool derives a 256-bit key from your passphrase using PBKDF2 (250,000 iterations, SHA-256) with a random salt generated fresh on every encryption, then encrypts with a random 96-bit IV. The salt and IV are prepended to the ciphertext and the whole thing is Base64-encoded into one copyable blob, so decryption only needs that blob and the original passphrase.
Because the salt and IV are random every time, encrypting the same text with the same passphrase twice produces two different outputs — this is expected and is what stops an observer from noticing that two encrypted blobs hide identical text.
Examples
Encrypting a short message
Text: "the launch code is 4821", Passphrase: "correct horse battery staple"
A Base64 blob — decrypting it with the same passphrase recovers the original text exactly.
How It Works
- Choose Encrypt or Decrypt.
- Enter the text (or, for Decrypt, the Base64 blob this tool produced).
- Enter a passphrase — the same one must be used for both encrypting and decrypting.
- Click Run to get the result.
FAQ
No. Key derivation and encryption/decryption both run entirely in your browser using the Web Crypto API — nothing is transmitted anywhere.
AES-GCM authenticates the ciphertext, so even a single changed character in the Base64 blob (from a copy/paste error, for example) makes decryption fail rather than return corrupted text. Re-copy the full blob and try again.
No — this tool works on text pasted into the browser, not file uploads. For encrypting files, use a dedicated file-encryption tool.
Only as strong as the passphrase itself — PBKDF2's 250,000 iterations make brute-forcing a weak passphrase slower, but a short or common passphrase is still the weakest link. Use a long, random passphrase for anything sensitive, similar to a strong password.