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COVIDSafe captures close contacts with the new Herald Protocol
COVIDSafe captures close contacts with the
new Herald Protocol
30 November 2020
Tags:  COVID-19 (/taxonomy/term/413)   COVIDSafe (/taxonomy/term/419)
Even though we have made a range of significant improvements to COVIDSafe, we continue to
look for ways we can improve the app further. Herald, a Bluetooth communication and range
finding protocol that supports contact tracing, is one such improvement.

The Australian Government’s response to the COVID-19 pandemic has focused on protecting
the health of citizens and the economic wellbeing of the nation. As part of this, Australia was
an early mover in implementing COVIDSafe as a digital contact tracing app that puts contact
tracers and health authorities at the centre of our pandemic response.  COVIDSafe will become
an even more important tool as COVID-19 restrictions ease across Australia and people move
around more.
COVIDSafe was launched on 26 April and since then we have delivered 14 updates, including
improvements in Bluetooth performance, privacy and security. The Australian technology
community’s feedback has been pivotal to the app’s development. These contributions have
directly driven important COVIDSafe performance enhancements that have benefited all users.
We will be giving the tech community the opportunity to review the source code and provide
feedback on the new Herald Protocol, ahead of it being released.
An explanation of Herald
The Herald Protocol employs several techniques (https://vmware.github.io/herald/) to improve
Bluetooth communication across a wide range of mobile devices. This provides contact tracing
apps with regular and accurate proximity information that helps make them highly effective, as
the updated Bluetooth Encounter Logging results below demonstrate.
Herald is a VMware-originated open source project (https://vmware.github.io). It is part of
VMware’s ongoing contribution towards the Linux Foundation Public Health initiative
(https://landscape.lfph.io/selected=herald). The initiative aims to use open source technologies
to help public health authorities across the world combat COVID-19.
The Herald website (https://vmware.github.io/herald/) provides further information, including
Detailed technical documentation (https://vmware.github.io/herald/docs) and a design guide
(https://vmware.github.io/herald/design) that outlines how Herald has been built.
Incorporating Herald into COVIDSafe
Incorporating Herald will further improve COVIDSafe’s performance, particularly when the app
is running in the background on iOS devices.
Herald has been designed to provide the same level of Android and iOS backward
compatibility as COVIDSafe currently does. This ensures COVIDSafe will continue to be
available across the wide range of mobile devices used by the Australian community.
It will also support the current COVIDSafe operating model, which has been designed and
optimised to meet Australia’s contact tracing needs, ensuring Health Officials are at the core of
our response efforts. It is important that any digital contact tracing solution assists Australian
health officials to manage the pandemic using our world-leading contact tracing processes.
The Herald difference
Testing of Herald in COVIDSafe has demonstrated a near 100% detection of close contacts in
the foreground and background across iOS and Android devices. It will give COVIDSafe an
‘excellent’ rating for encounter detection on iPhone to iPhone, and iPhone to Android digital
handshakes.
Our testing results showed:
increased Bluetooth performance, even in background, leading to more encounters being
captured between devices, especially between iOS devices
no substantial change in battery usage when compared to current COVIDSafe – on
average 1 to 3 per cent per hour, depending on the age of the phone and its battery
capacity.
Further details on COVIDSafe’s Bluetooth performance improvements and battery performance
are provided below.
Rigorous analysis and testing by cyber security experts has shown that the Herald-enabled
COVIDSafe app continues to provide users with world leading privacy and security protection.
Please note: Some incorrect reports say that the new Herald Bluetooth Protocol for COVIDSafe
is the same protocol that the UK NHS abandoned earlier this year. This is false, as it is not the
same protocol. Herald has been developed and open sourced as part of the Linux Foundation
Public Health initiative in July 2020. As Herald is an open source technology that is available at
no cost, the implementation of Herald will be covered from existing COVIDSafe resources.
Call to the Australian Tech Community: Improve COVIDSafe and
other contact tracing apps
Australia will be the first country in the world to implement the Herald protocol.
We value this opportunity for your feedback and suggestions to help us, and other countries
that may adopt Herald, to build stronger contact tracing apps that best meet their country
specific contact tracing needs.
We welcome your feedback on the pre-release Herald-integrated COVIDSafe source code
directly in the GitHub repository for iOS (https://github.com/AU-COVIDSafe/mobile-
ios/tree/herald) or for Android (https://github.com/AU-COVIDSafe/mobile-
android/tree/herald) or through xxxxxxxx@xxxxxxxxx.xxx.xx (mailto:xxxxxxxx@xxxxxxxxx.xxx.xx).
We are engaging as early as possible with the technology community to seek your valuable
feedback on the code. We are still testing the pre-release code so in some cases it includes
logging code that will be removed prior to launch. 
We will review all feedback and where appropriate, add it to our backlog for prioritisation in a
COVIDSafe update. We’ve shown our commitment to working with the technology community
as we’ve developed COVIDSafe so far and we’d appreciate your patience as we work through
feedback on the Herald protocol. We value your feedback and it’s an important part of making
sure we continue to have a world-leading contact tracing system.
COVIDSafe Bluetooth Encounter Logging Results
COVIDSafe Bluetooth performance summary results with Herald
27 November 2020
Android to Android
Android to iOS
iOS to iOS
Active -> Active
Excellent
Excellent
Excellent
Active -> Background
Excellent
Excellent
Excellent
Unlocked
Active -> Locked
Excellent
Excellent
Excellent
Locked -> Locked
Excellent
Excellent
Excellent
Encounter logging: Excellent (80% to 100%), Good (50% to 80%), Moderate (25% to 50%), Poor
(25% or below). Shaded cells show areas of improvement compared to previous test results.
COVIDSafe Bluetooth performance summary results prior to Herald 
1 August 2020
Android to Android
Android to iOS
iOS to iOS
Active -> Active
Excellent
Excellent
Excellent
Active -> Background
Excellent
Good
Excellent
Unlocked
Active -> Locked
Excellent
Good
Good
Locked -> Locked
Excellent
Good
Moderate
 
26 May 2020
Android to Android
Android to iOS
iOS to iOS
Active -> Active
Excellent
Excellent
Excellent
Active -> Background
Excellent
Good
Excellent
Unlocked
Active -> Locked
Excellent
Moderate
Good
Locked -> Locked
Excellent
Moderate
Moderate
 
13 May 2020
Android to Android
Android to iOS
iOS to iOS
Active -> Active
Excellent
Excellent
Excellent
Active -> Background
Excellent
Good
Excellent
Unlocked
Active -> Locked
Excellent
Moderate
Moderate
Locked -> Locked
Excellent
Moderate
Moderate
 
26 April 2020
Android to Android
Android to iOS
iOS to iOS
Active -> Active
Excellent
Excellent
Excellent
Active -> Background
Excellent
Good
Good
Unlocked
Active -> Locked
Excellent
Poor
Moderate
Locked -> Locked
Good
Poor
Poor
Encounter logging: Excellent (80% to 100%), Good (50% to 80%), Moderate (25% to 50%), Poor
(25% or below).
COVIDSafe Battery Usage Results
Battery usage tests were conducted using six devices. Results found that a device running
Herald uses between 1.3% and 3.2% of battery power per hour. The exact number varies on
each device, depending on the age of the phone model, age of the phone, and its battery
capacity.
The tests below were performed on devices that only had the Herald-enabled COVIDSafe app
installed.
COVIDSafe Herald-integrated battery usage summary results
 
1 hour
8 hours
12 hours
Samsung J6
1.3%
10.2%
15.3%
iPhone 6 Plus
1.6%
12.9%
19.4%
Samsung A20
1.7%
13.4%
20.2%
Samsung A5
2.0%
16.1%
24.2%
Google Pixel 2
2.8%
22.0%
33.1%
iPhone 6S
3.2%
25.8%
38.7%
The measurements reflect the total battery use for running both the device’s operating system
and the Herald-enabled COVIDSafe app on each device.
Visit the COVIDSafe website (https://covidsafe.gov.au/) for more information or to
access the application source code.
For media enquiries email us at xxxxx@xxx.xxx.xx (mailto:xxxxx@xxx.xxx.xx)
For other enquiries email us at xxxx@xxx.xxx.xx (mailto:xxxx@xxx.xxx.xx)
© Commonwealth of Australia. With the exception of the Commonwealth Coat of Arms and
where otherwise noted, this work is licensed under the CC BY 4.0 license.