Encrypted email provider Lavabit is coming back, with improved protection and security.

Lavabit founder Ladar Levison says relaunching the secure email service will protect US Constitution-guaranteed values of freedom, justice and liberty.

Email is “the heart of our cyber-identities”, he said.

Levison closed down Lavabit in 2013 when United States authorities were seeking silent interception of user communications, so as not to have to hand over digital decryption keys under a search warrant.

The new version is built around the Dark Internet Mail Environment (DIME) – and end-to-end encryption standard developed with Kickstarter crowdfunding, which provides automated and federated encryption capabilities and can work with a range of different service providers.

The new Lavabit is intended to enhance to function and usability of email encryption offered by existing solutions such as OpenPGP and S/MIME, including automatically scrambling messages and their metadata.

Levison says Lavabit is using hardware security modules (HSM) in line with the US Federal Information Processing Standard 140-2, which means digital keys can be used without being accessed directly.

To protect the HSM key, Lavabit creates a passphrase for the system supervisor account blindly, locking out any service provider staffers.

“Any attempt to extract the key will trigger a tamper circuit causing the key to self-destruct,” Levison said.

Versions of DIME can already be used with mail clients such as Mozilla Thunderbird and Microsoft Outlook, Outlook Express and Windows Live Mail.