Encrypt & Decrypt Text Online

Encrypt and Decrypt Text with AES-GCM, RC4, or Caesar

Transform text with three supported methods. Use AES-GCM with a passphrase for authenticated encryption, or select legacy RC4 and the simple Caesar shift only when compatibility or demonstration work calls for them.

Key Features

  • AES-GCM with a PBKDF2-derived 256-bit key, random salt, and initialization vector
  • RC4 mode for compatible legacy ciphertext
  • Caesar cipher with a configurable numeric shift
  • Copy and text-file download controls for the generated result

How to Use This Tool

  1. Select AES-GCM, RC4, or Caesar and choose Encrypt or Decrypt.
  2. Enter the source text and the passphrase, text key, or numeric shift required by that method.
  3. Run the transformation, then copy or download the result.
  4. For decryption, keep the original method and secret exactly the same as those used to encrypt.

Important to Know

  • AES-GCM is the suitable choice among these options for modern authenticated encryption.
  • RC4 is a legacy cipher and Caesar is trivially reversible; neither should protect sensitive data.
  • The tool cannot identify an unknown cipher or recover a missing passphrase, key, or shift.

Frequently Asked Questions

Which encryption methods are available?

Choose AES-GCM, RC4, or a Caesar cipher. AES-GCM uses a passphrase, RC4 uses a text key, and Caesar uses a numeric letter shift.

How does the AES-GCM option format encrypted text?

It derives a 256-bit key from the passphrase with PBKDF2 and SHA-256, then packages the random salt, initialization vector, and ciphertext as Base64 text.

Can this decrypt any encrypted text?

No. Select the matching cipher and provide compatible ciphertext plus the same passphrase or Caesar shift used for encryption.

What are the RC4 and Caesar options for?

RC4 is a legacy stream cipher and Caesar is a simple letter-shift cipher. They are useful for compatible inputs, demonstrations, and reversible text transformations.

Can I copy or download the encrypted result?

Yes. After encryption or decryption, copy the output or download it as a text file.