Most municipal emergency response plans include some form of emergency communication protocols. Satellite, private radio, and other solutions all play their part.

But the reality is, most city staffers will not have access to a satellite phone or radio, and many will be somewhere in the field doing their job to address the situation at hand.

What’s the best way to communicate with them? The fallback for most will be consumer grade Instant Messaging (IM) products. With phone lines jammed, texting will be the most viable method of sending short, mission critical messages and photos of the situation amongst a team.

But are consumer grade Instant Messaging apps safe to use for emergency communications?

The answer is no. Most use unencrypted plain text messages, and worse, no way to fully authenticate the person you are communicating with is who they say they are, and that there is no “man-in-the-middle” listening in on your conversation.

What is the solution?

Municipal emergency response

Pre-determining a secure method of team communication before an emergency event could prevent a bad situation getting even worse. Municipal teams should have an easy way to quickly secure a 100% private channel using any available network – be it cellular, or even a public WiFi network. The handsets should be mobile and something everyone has access to – such as their personal smartphone!

The British Ministry of Defence had a very similar need for their coalition forces. Those dropped into foreign territories without satellite equipment needed to create secure channels amongst each other from any device, and over any available network.

They turned to the world renowned cyber-security team at the University of Oxford for a solution, who were more than up to the challenge.


The result? An authentication protocol which quickly creates secure channels between two or more endpoints for transmission of sensitive communication data.

Called Hash Commitment Before Knowledge (HCBK), the protocol has been patented in both European and US markets, and is now available commercially for the first time in Scrambl, a highly secure Instant Messaging communications app for smartphones.

Scrambl allows municipal staff teams to have a secure means of communicating amongst themselves at a moment’s notice. Just open the app on any iOS device, enter the email address of the person you’d like to connect with, and Scrambl runs an authentication process to create an encrypted, secure channel between you and the other party.

To save time in a crisis, teams can set up the channels in advance. All they have to do is open the app, and they’re ready to communicate securely right away with the team.

Scrambl also works with groups – just add more people to the channel as required, for the ability to chat and share image files in a group session.

Download Scrambl


Scrambl VPC diagram

Scrambl creates authenticated private channels between users. These ‘Scrambl channels’ provide end to end encryption of all messages, with keys only ever being stored on the devices – never on a server.

But most importantly is how Scrambl authenticates users on each end of the channel, — thereby ensuring there can be no “man-in-the-middle” compromising its encryption or privacy.

For professionals requiring absolute privacy in their communications, there is no safer way than Scrambl.


Scrambl is the first commercial deployment of the HCBK (Hash Commitment Before Knowledge) protocol, invented by OxCEPT, a team of security experts spun out from the University of Oxford.

Developed to protect MOD soldiers in the coalition battlefield, HCBK provides military-grade authentication over any network, and has been validated and deemed virtually unbreakable by an independent panel of security experts.