Encrypt & Decrypt Text Online (AES, 3DES) — Free
Runs 100% in your browser — your files never leave your device.
Share a secret note, protect a config value, or reverse a ciphertext you received. Pick AES, TripleDES, RC4, or Rabbit, enter a passphrase, and encrypt — the output is a portable base64 string anyone with the same passphrase and algorithm can decrypt here. Keys never leave your device.
How it works
- 1
Choose a cipher
AES is the default; TripleDES, RC4, and Rabbit also work.
- 2
Enter text and passphrase
The passphrase is the shared secret — send it separately.
- 3
Encrypt or decrypt
Get a base64 ciphertext, or paste one to recover the original text.
About this tool
Real encryption, in your browser
The tool applies AES — the standard symmetric cipher — to your text using the passphrase you choose: the same technology protecting disk encryption and secure protocols. Paste ciphertext to decrypt, or plaintext to encrypt; the result is portable base64.
The passphrase is the security
AES is unbroken; passphrases are the weak point. A short or guessable passphrase reduces the cipher to a lock on a paper door — use long, unique passphrases. The tool never stores or transmits your passphrase or your text; everything computes locally.
Round-trip with the right passphrase
Decryption requires the exact passphrase used for encryption — there is no recovery. The output is base64, so ciphertext travels safely through any text channel: email, chat, config files.
Frequently asked questions
Is this secure enough for real secrets?
AES with a strong passphrase is genuinely secure for text secrecy. The passphrase strength is the whole game — length beats complexity, and uniqueness beats cleverness.
What happens if I lose the passphrase?
The data is unrecoverable — that is the definition of working encryption. There is no backdoor, reset, or support channel; the key is the passphrase.
Where do I share the passphrase?
Never in the same channel as the ciphertext — tell the recipient in person, by phone, or through a different system. Encrypted message plus passphrase in one place equals no encryption.