Free Encryption/Decryption Tool

The Encryption/Decryption Tool is a free online utility that encrypts and decrypts text using AES, DES, and other cryptographic algorithms.

Yes, it is completely free with no registration required. All encryption and decryption happens client-side in your browser, ensuring your data never leaves your device.

The Encryption/Decryption Tool supports AES (128/256-bit), DES, Triple DES, and other algorithms for varying levels of security.

Absolutely. The Encryption/Decryption Tool processes everything client-side in your browser. No data is uploaded to or stored on any server. Your content remains private on your device at all times.

Yes, the Encryption/Decryption Tool is fully responsive and works on smartphones and tablets. You can use it on any device with a modern web browser -- no app download required.

No account or registration is needed. Simply open the Encryption/Decryption Tool in your browser and start using it immediately. There are no sign-up walls or usage restrictions.

Simply enter your input in the provided field, adjust any settings to your preference, and the tool will process it instantly. You can then copy the result to your clipboard or download it.

The Encryption/Decryption Tool works in all modern browsers including Chrome, Firefox, Safari, Edge, and Opera. For the best experience, use the latest version of your preferred browser.

Both modes use the same AES cipher, but they handle integrity differently. AES-GCM is authenticated encryption: it scrambles your text and attaches a built-in integrity tag, so if the ciphertext is altered even slightly, decryption fails cleanly instead of returning corrupted output. That makes it the safer default and the reason it is recommended for new work. AES-CBC is an older, widely supported mode without that built-in authentication, so it cannot detect tampering on its own; it is offered mainly for compatibility with systems that expect it. In practice, GCM also uses a shorter 12-byte initialization vector versus 16 bytes for CBC. Unless you specifically need CBC for an existing workflow, choose AES-GCM. You can switch between the two modes in the tool's algorithm dropdown before encrypting.

You never type a raw AES key directly. Instead you enter a passphrase, and the tool derives the actual key from it using PBKDF2 with 100,000 iterations of SHA-256 over a fresh random 16-byte salt. PBKDF2 is deliberately slow, which sharply raises the cost of brute-forcing a weak passphrase because an attacker must repeat all those iterations for every guess. The random salt means the same passphrase produces a different key each time, defeating precomputed lookup attacks. A new random initialization vector is also generated for every encryption, so encrypting identical text twice never yields the same ciphertext. The salt, IV, and ciphertext are packed into the single string you copy, so you only need to remember the passphrase, algorithm, and key size to decrypt later. Enter your text and passphrase above to try it.

All three key sizes use the same AES cipher and are considered secure; the number refers to how long the derived key is. A 128-bit key is already strong enough for the vast majority of real-world uses and would take an impractical amount of computing power to brute-force. 256-bit gives the largest security margin and is the level associated with top-secret government classifications, which is why it is the tool's default. 192-bit sits in between. For most people the practical difference is negligible, so 256-bit is a sensible choice when in doubt. The one rule that matters is consistency: you must decrypt with the exact same key size used to encrypt, or it will fail. Pick your key length from the dropdown above before encrypting, and use the same setting when you decrypt.

A correct passphrase alone is not enough — decryption only succeeds when the algorithm, key size, and passphrase all match the values used at encryption. If you encrypted with AES-GCM at 256-bit but try to decrypt with AES-CBC or 128-bit, it will fail even with the right words. The same applies to the output format: ciphertext copied as Base64 must be decrypted as Base64, not hexadecimal. Another common cause is incomplete copying — the salt and IV are packed into the start of the encrypted string, so a missing or truncated character breaks decryption. With AES-GCM specifically, any tampering or corruption trips the built-in integrity check and stops decryption deliberately. When it fails, recheck those three settings and confirm you pasted the full string. Re-enter your settings above to match and try again.

No — sharing both in the same message defeats the whole point of encryption. If an attacker intercepts a single email or chat that contains the ciphertext and the passphrase side by side, they can decrypt it instantly, and the strong AES cipher provides no protection at all. The standard practice is out-of-band sharing: send the encrypted string one way, such as email or a chat app, and deliver the passphrase through a separate channel like a phone call or a different messaging app. Because this tool derives the key from your passphrase, the ciphertext is only as secure as the passphrase behind it, so use a long, unique one — 12 or more characters mixing cases, digits, and symbols, or the built-in generator. The strength meter above rates your passphrase before you encrypt.