Android Application Marketing

I have developed an android application for saving passwords in an encrypted form and view it by using pattern lock. Password generator tools also its part which is a handy way to create strong passwords with required [login to view URL] this app if the user is changing the device he/she can export saved passwords and import it back in new device by using the same pattern that was used while exporting. This app does not use the internet because we save nothing. It is paid app with no advertisement and no in-app purchase. I am regularly updating its features but I don't have marketing skills to get downloads. If someone is interested to help me increase its downloads then bid on this project. I want at least 350 downloads + Good Rating + Reviews. I have 500 promotion code which will be used to download this app free of cost I will provide that. Application Link [login to view URL]