Skizzle is a chrome add-on that helps users share end-to-end encrypted files over email. It is extremely easy to use and works right alongside your regular email workflow. It uses blockchain to manage your keys and file access permissions so that users do not have to deal with them. This ensures that no one except the sender and recipient has access to files and keys, not even Skizzle. Users can retrieve their keys even if they lose them. The receiver need not be an existing user - you just need their email ID. You can revoke access to files for a specific user. It is intuitive and comes with a generous free plan. Features are also available as SDKs for custom application development.