... based on the boolean XOR operation and Javascript

Decryption: Enter your encrypted text message and your secret password into the form fields abovd and press "decrypt" to see the plaintext.

Encryption: Enter your plaintext and password in the form fields below and press "encrypt" to see the encrypted text.

How it works: A JavaScript, which is embedded in this web page and hence is executed locally on your computer, generates an encryption key with the same length as your text using a pseudo-random number generator that uses a hash of the password as the seed. A random salt that is used in the encryption process is appended to the end of the encrypted text. The generated key is then char-wise XORed with the given text in order to decrypt or encrypt it. The security of the encrypted data is dependent on the length and randomness of the key.