Which webhost are you reffering to? B4j provides jB4XEncryption library you can use it should be compatible with the whole B4X frenchise. If you sign up somewhere it usually comes with a mySQL database and PHP. On server side you can manage encrytion through MD5, SH1, Crypyt, Bcrypt and Hash-strings by using PHP. Or set up your own server, but as I understood from your question this is not an option. I've seen your many posts about ABMaterials which seems to be the hot trend for everybody. Google is on top for a reason. However, it's important to do something with past knowledge and MySQL+PHP+CSS is truly POWERFUL. You might want to combine encryption shemes with eachother to cook up a stronger security, and never decrypt your string. Just compare the Hash result for optimal safety.