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Free AES-256 Encryption and Decryption

Encrypt or decrypt text with AES-256, the modern symmetric encryption standard, using a password of your choice.

100% Free No Signup Works on all devices

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Key Features

Instant Calculation

Get accurate results in real time with our optimized algorithm.

Mobile Friendly

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Privacy Focused

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100% Free

No hidden costs. This tool is completely free forever.

AES (Advanced Encryption Standard) is the symmetric encryption algorithm used to protect everything from HTTPS connections to encrypted hard drives — it's the current industry standard, unlike the classical ciphers found elsewhere on this site.

This tool encrypts or decrypts text using AES-256 in CBC mode, with a real password-based key derivation function rather than using your password directly as the encryption key.

How it works

Enter your text and a password. To encrypt, a random 16-byte salt and a random 16-byte initialization vector (IV) are generated, and your password is combined with the salt using PBKDF2 (100,000 rounds of SHA-256) to derive a proper 256-bit key. The text is then encrypted with AES-256-CBC, and the salt, IV, and ciphertext are combined into one base64-encoded block you can copy. To decrypt, paste that block back in with the same password — the tool extracts the salt and IV, re-derives the same key, and reverses the encryption.

  1. Enter mode.
  2. Enter text.
  3. Enter password.
  4. Click Calculate to see your results.

Examples

Encrypting a message

Encrypting "Attack at dawn" with a password produces a different base64 block every time (because the salt and IV are random), but decrypting any of them with the correct password always returns "Attack at dawn".

Who should use it

  • Encrypting sensitive notes or short messages before storing or sharing them.
  • Learning how modern password-based encryption (salt + PBKDF2 + AES-CBC) actually works in practice.

Industry applications

  • Data security and encryption software
  • Secure messaging and storage systems

Advantages

  • AES-256 is a real, modern, industry-standard cipher — not a classical/historical one.
  • Uses proper password-based key derivation (PBKDF2) instead of a naive password-as-key approach.

Limitations

  • Security still depends on choosing a strong password — this tool can't protect a weak, guessable one.
  • RSA can only encrypt very short messages directly — for this tool that's not a concern since AES has no such limit, but the point still holds that a cipher's theoretical strength doesn't remove the need for good password hygiene.

Common mistakes to avoid

  • Losing the password used to encrypt — there's no way to recover the original text without it, by design.
  • Copying only part of the base64-encoded result when decrypting — the salt, IV, and ciphertext are all packed into that single block and all of it is needed.

Best practices

  • Use a long, unique password rather than a short or reused one — PBKDF2 slows down brute-force attempts but can't make a weak password strong.
  • Keep a secure backup of anything important you encrypt — if you lose the password, the data is unrecoverable.

Tips

  • If you need to share encrypted text with someone else, share the password through a separate, trusted channel — never alongside the encrypted text itself.

Frequently asked questions

Yes, with no signup and no limit on how many conversions you run.
Your input is processed to generate your result and isn't retained afterward — see the Privacy Policy for full details.
Because a new random salt and IV are generated every time you encrypt — this is intentional and is what keeps identical messages from producing identical ciphertext, which would otherwise leak information.
Yes — AES-256 is the current real-world encryption standard, used by governments, banks, and secure messaging apps. This tool's security in practice depends entirely on choosing a strong, unique password, since PBKDF2 slows down but can't fully prevent password-guessing attacks against a weak password.
The tool tells you decryption failed rather than silently returning garbled text — AES-CBC decryption with the wrong key almost always fails a data-integrity check rather than producing a plausible-looking wrong answer.

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