A computer implemented method for encrypting one or more files and wrapping them in an HTML document. The HTML document contains the encrypted files, the necessary code to decrypt the files, as well as user interface code to receive a passphrase input from a user. The HTML document can be opened using any modern web browser, to obtain the original files using the same passphrase with which the encryption was performed. This offers a convenient way of sharing encrypted files via email or cloud file sharing services using a platform independent file format (without having to install any additional software).