AES Encryption & Decryption Tool

Encrypt and decrypt text with AES-GCM or AES-CBC using this free online tool. Password-based key derivation via PBKDF2. No sign-up required, runs entirely in your browser.

What Is AES Encryption?

AES (Advanced Encryption Standard) is a symmetric-key encryption algorithm adopted by the U.S. government and used worldwide to protect sensitive data. It operates on fixed 128-bit blocks and supports key sizes of 128, 192, or 256 bits. AES-GCM (Galois/Counter Mode) provides both encryption and authentication in a single operation, detecting any tampering with the ciphertext. AES-CBC (Cipher Block Chaining) is a classic mode that chains blocks together but does not include built-in authentication. This tool derives a 256-bit AES key from your password using PBKDF2 with 100,000 iterations and a random salt, ensuring strong key derivation even from weak passwords.

How to Use This AES Encryption Tool

  1. Select the Encrypt or Decrypt tab.
  2. Choose the algorithm (AES-GCM is recommended for authenticated encryption).
  3. Select the output format — Base64 for compact output or Hex for a hexadecimal representation.
  4. Enter your plaintext (or ciphertext for decryption) and a password.
  5. Click the button — the result appears below with a copy option.

Common Use Cases for AES Encryption

  • Encrypting sensitive notes or messages — Protect private messages, API keys, or credentials before sharing them through insecure channels like email or chat.
  • Client-side encryption before cloud upload — Encrypt files or data in the browser before uploading to cloud storage, ensuring the provider cannot read your content.
  • Testing encryption workflows — Developers can quickly test AES encryption and decryption logic, verify output formats, and debug interoperability issues.
  • Secure clipboard sharing — Encrypt text, share the ciphertext with a colleague, and provide the password through a separate channel for secure communication.

FAQ

What is the difference between AES-GCM and AES-CBC?
AES-GCM provides both encryption and authentication (AEAD) — it detects if the ciphertext has been tampered with. AES-CBC only encrypts and does not verify integrity. For most use cases, AES-GCM is the recommended choice.
How is the encryption key derived from my password?
The tool uses PBKDF2 with SHA-256, 100,000 iterations, and a random 16-byte salt to derive a 256-bit AES key from your password. The salt is prepended to the ciphertext so decryption can regenerate the same key.
Can I decrypt data encrypted by another AES tool?
Only if the other tool uses the same format: PBKDF2 key derivation with matching parameters, and salt + IV prepended to the ciphertext. This tool uses its own format, so it is designed to decrypt its own output.
Is my password or data sent to a server?
No. All encryption and decryption happens locally in your browser using the Web Crypto API. No data or passwords ever leave your device.

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