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Encrypt and decrypt text using symmetric key algorithms: AES-GCM, AES-CBC, ChaCha20-Poly1305, TripleDES, and more. Select the algorithm, choose the Encrypt or Decrypt, enter the text and key, and execute the operation. Algorithms marked with ⚠ are obsolete; use them only for compatibility.

AES in CBC mode. Widely compatible. Requires a random IV per message.

Keys and parameters
Entrance

How it works

Symmetric encryption uses a single secret key to both encrypt and decrypt. Whoever holds the key can do both operations, so it must be shared over a secure channel.

Choose the algorithm, generate or paste the key (and the IV or nonce when applicable), type text or upload a file, and encryption happens instantly in your browser. The result can be shown in hexadecimal or Base64.

AES-GCM and ChaCha20-Poly1305 are authenticated ciphers (AEAD): besides hiding the content, they detect any tampering. AES-CBC and AES-CTR do not authenticate, and DES, 3DES, RC4, and Rabbit are included only for compatibility with legacy systems.

Examples

AES-GCM · 256 bitsPlaintext → ciphertext in Base64, with the authentication tag included.
AES-CBC · 256 bits + IV 128 bitsRequires a random IV per message; with the same IV and key, the same text would always produce the same result.Never reuse an IV or nonce with the same key, especially in GCM and CTR modes: it compromises the security of the encryption.
ChaCha20-Poly1305 · nonce 192 bitsAuthenticated alternative to AES-GCM, ideal on devices without AES-NI acceleration.

Use cases

  • Encrypt a text or file to store or send it protected, sharing the key over a separate channel.
  • Decrypt received data using the correct key and IV.
  • Test interoperability with another system by adjusting algorithm, mode, key size, and IV.
  • Understand in practice the differences between modes: authenticated GCM versus unauthenticated CBC or CTR.

Frequently asked questions

What is the difference between symmetric and asymmetric encryption?

Symmetric uses the same key to encrypt and decrypt; asymmetric uses a public and private key pair. Symmetric is faster, but requires sharing the key securely.

Which algorithm should I use?

For general use, AES-GCM is the recommended standard. ChaCha20-Poly1305 is an excellent alternative on devices without AES-NI acceleration. Avoid DES, 3DES, RC4, and Rabbit except for compatibility.

What is the IV or nonce and why must I generate it?

It is a random value combined with the key on each message so that the same text does not always produce the same ciphertext. It must be unique per message and never reused with the same key.

What should the key be like?

Random and of the size indicated by the algorithm (for example 256 bits for AES-256). Use the button to generate a secure key; do not use passwords or predictable values.

Why do DES, 3DES, or RC4 appear if they are insecure?

Only to decrypt data generated by old systems that still use them. Do not use them to protect new information.

Are my text and key sent to a server?

No. All encryption and decryption happen locally in your browser; neither the content nor the key leaves your device.

See also