Encryption Playground: AES-256-GCM Encrypt/Decrypt Online
Encrypt text using AES-GCM with a passphrase or raw key. Decrypt messages. Educational and client-side secure.
Try the free online tool mentioned in this guide:Encryption Playground
AES-GCM encryption basics
AES-GCM (Galois/Counter Mode) is a symmetric encryption algorithm that:
- Encrypts — scrambles plaintext so only someone with the key can read it.
- Authenticates — verifies the data hasn't been tampered with.
- 256-bit key — extremely strong (2^256 possible keys).
AES-GCM is used in: - TLS/HTTPS (your browser uses it). - File encryption tools (7-Zip, VeraCrypt). - Password managers (1Password, Bitwarden).
Symmetric vs asymmetric encryption
Symmetric (AES-GCM) — same key encrypts and decrypts. Fast, but both parties need the key.
Asymmetric (RSA) — public key encrypts, private key decrypts. Slower, enables key exchange.
For this playground, we use symmetric: you encrypt with a passphrase, decrypt with the same passphrase.
How encryption works in MyDevTools
1. Raw key mode — Provide a 32-byte hex key (256 bits). Use for deterministic encryption. 2. Passphrase mode — Enter a password. PBKDF2-SHA256 derives a 256-bit key, then encrypts.
The output is a JSON bundle:
`json
{
"ciphertext": "...",
"iv": "...",
"tag": "..."
}
`
Share this bundle; decrypt by pasting it back with the same passphrase.
Encryption workflow
1. Type or paste plaintext. 2. Choose mode: raw key or passphrase. 3. Encrypt. Output is a JSON bundle. 4. Share safely — paste the JSON to someone. 5. Decrypt — they paste the JSON and enter your passphrase.
When to use
- Learning — understand how encryption works.
- Quick encryption — share sensitive data via email (encrypted, not plaintext).
- Testing — verify encryption/decryption in applications.
- Not for production — use dedicated security libraries and key management.
Frequently asked questions
Is this secure for real use?
Encryption is secure, but browser-based key management is not enterprise-grade. Use a password manager or key vault for production secrets.
What if I forget the passphrase?
The encrypted data is unrecoverable. Always store passphrases securely.
Can I encrypt files?
Current version handles text. For files, use dedicated tools like 7-Zip, VeraCrypt, or gpg.