Two email providers forced to close their services in the wake of the Edward Snowden revelations on mass surveillance have proposed a new open standard for secure email that would be harder for security services and others to eavesdrop upon.

The encrypted email service Lavabit, and Silent Circle, a firm also encrypting phone calls and texts, are the founding members of the Darkmail Alliance, a service that aims to prevent government agencies from listening in on the metadata of emails.

The metadata is the information bundled up with the content of an email such as that showing the sender, the recipient and date the message was sent.

Conventional email can never be made fully secure because the standard requires some metadata to be sent unencrypted.

Mike Janke, Silent Circle's chief executive and co-founder, said that this factor meant the medium was "fundamentally broken".

The new service was revealed at the Inbox Love conference in California on Wednesday. The alliance hopes to bring on board potential partners.

"We want to get another dozen to two dozen email providers up and running on Darkmail architecture so that at any one time citizens of the world can choose two dozen email providers to get their email service from," said Janke.

The ultimate aim is to get the big email providers, such as Microsoft, Yahoo! and Gmail, using the new standard too.

The Darkmail Alliance aims to fix many of the problems affecting the old standard. "The existing email architecture is 40 years old, and it's what allows the world's surveillance community, hackers and other data mining companies, to get [users'] data," Janke told the Guardian.

He said that the services Lavabit and Silent Mail kept too much data on the provider's server. "So what happened is you saw nation states can go to an email provider and coerce them into turning over the keys and decrypting.

"Look at Lavabit, they were coerced by law. The same thing happened to Hushmail. And on top of that, you've got big data companies like Microsoft, Yahoo! [Google] and 50 others that offer these free services that are actually mining your email for keywords. And selling it and packaging it up for ads. So it's broke, it's absolutely broke."

Lavabit, which was once used by the US whistleblower Snowden, was forced to shut down in July 2013 when its founder, Ladar Levison, was ordered to hand over the keys to all his users' private data. Facing a fine of $5,000 a day, he complied, then switched off the servers.

Levison said: "I'm worried about how we're just a blink technologically away from becoming a totalitarian state, where our government is watching us all the time.

"You have to remember that the email protocols that we're using today were developed in the 70s when there were only a handful of people on the internet, or back then it was called Darpanet, and everybody trusted everybody else.

"Security was never baked into the protocols, it's really become an afterthought. And as a result, messages [are] passed over the internet in plaintext. It's hard to develop a system which is backwards compatible but is secure by default. In fact it's impossible."

The proposal of the alliance, it says, is as close to being compatible with conventional email as can be; users can send and receive insecure emails with contacts on normal services, and it is only when an email is sent between two accounts within the alliance that the message is encrypted and routed from one peer to the other without going through a central server.

That mechanism would prevent the kind of metadata collection routinely carried out by intelligence agencies, such as that exposed by Snowden, the alliance says.

Janke said: "We always say we will be successful if, in three years, 50% of the world's email are sent through this Darkmail architecture. That's why we teamed up [with Lavabit] … This whole unique engine that we developed, we're putting it out open source. We think it's our responsibility to do that."

The focus is on the mid-to-small providers initially, but Janke said he had one bigger target in mind.

"The interesting part is, at Inbox Love it's going to be all the big [providers], Microsoft, Yahoo!, Gmail – you name it. And we know that eventually, as we start to proliferate what we call the email 3.0 architecture, they're going to have to decide. It's going to be very difficult for them."

The ball was going to be in the court of big email providers. "What are they going to do?" said Janke. "Are they going to actually join in? Or are they going to kick the can down the road?"