Buttercup by MadDev

Manage your online identities and credentials with Buttercup: An open-source, free and secure credentials manager. Buttercup uses the strongest industry techniques to encrypt and store your details in a variety of locations of your choosing. Use Google Drive, Dropbox, WebDAV or local files, all via the desktop application, to remotely or locally access your vault. Save new logins to your secure archives.

This extension requires the desktop application to function. Please note that this extension does not support Android platforms.