Base64 is a way to encode binary data into an ASCII character set known to pretty much every computer system, in order to transmit the data without loss or modification of the contents itself. For example, mail systems cannot deal with binary data because they expect ASCII (textual) data. So if you want to transfer an image or another file, it will get corrupted because of the way it deals with the data. Note: base64 encoding is NOT a way of encrypting, nor a way of compacting data. In fact a base64 encoded piece of data is 1.333… times bigger than the original datapiece. It is only a way to be sure that no data is lost or modified during the transfer.