2. • As a result of globalization, new pandemics
have the potential to spread like wildfire
around our planet
• The last decade has seen an alarming increase
in the number of new infectious diseases cross
over from animals to people
• Until we address the root causes (food supply
chain, urbanization, biodiversity loss, etc.), we
need to be prepared for new pandemics
Threat of Pandemics
3. • The economic impact of pandemics can be
devastating. Millions unemployed and many
more facing an uncertain future
• Unless we make major breakthroughs in
medical science, it will always take time to
create effective treatments and vaccinations
• Many businesses will simply not be able to
survive another wave of lockdowns in the face
of a new pandemic
Economic Challenges
4. SafetyScore
SafetyScore allows us to take back control.
We can keep people safe while keeping the
economy and critical industries open.
7. • SafetyScore calculates a score for everyone
based on the encounters they've had with
potentially infected people
• Authorities can verify an individual's
SafetyScore by simply scanning a QR code on
the user's app
• Being able to assess people's risk levels gives
countries a powerful tool to contain epidemics,
save lives, and keep economies alive
SafetyScore Health Passport
Scanning ...
14:18
Verified.
Entry Granted
14:18
92
8. • Places like universities, offices, restaurants, and
bars can operate safely by simply checking
people's SafetyScore before letting them in
• This helps to keep premises safe. Governments
can regulate the required Safety Levels on a
regional basis depending on the premise type
• SafetyScore empowers communities to self-
manage their risk so that local economies can
function while keeping people safe
Keeping Businesses Open
SafetyScore 11
63
85
67
21
9971
74
73
82 60
68
9. Traffic Light System
26
13:27
Nov 22
13:27
45
18:11
Nov 9
18:11
SAFE ON ALERT SELF-ISOLATE
Unrestricted Access Restricted Access at Large Events Regulated Access
10:52
88
10:52
Oct 5
10. SafetyScore Air Bridges
• SafetyScore enables people to visit other
Air Bridge countries without the need for
quarantine
• Governments can limit their exposure to
foreign infection risk by checking people's
SafetyScore before letting them in
• Governments specify the Air Bridge
countries that they trust, and this will be
factored into the verification process
12. SafetyScore
SafetyScore takes a radically different approach
to first-generation contact tracing apps built on
the Apple/Google framework
13. • SafetyScore uses Bluetooth on mobile phones
to detect others that come in close proximity
to a user
• Unlike first-gen apps which broadcast random
IDs over Bluetooth, SafetyScore broadcasts
cryptographic public keys
• This allows us to establish secure
communication channels between users that
will remain private from others
Proximity Detection
10:42 11:15 13:28
14. SafetyScore
distributes risk
Patient confirms
diagnosis
Health official
checks patient
First Degree
Contacts
Second Degree
Contacts
82
-10
71
-20
11
-9
15-6
85
-2
09
-17
• Health officials certify when someone is infected.
This propagates risk to the contact chain of the
infected person, updating SafetyScores
• Unlike first-gens apps that only notify direct
contacts, SafetyScore also propagates risk to
indirect contacts, improving accuracy
• If a person's score drops below a threshold,
governments can use this to prioritize access to
testing, treatment, and benefits
Risk Propagation
17. • A range of factors are brought together to
make an individual's SafetyScore as accurate as
possible while maintaining privacy
• The score includes risk exposure from direct
and indirect contacts, recent test results, and
the Geo-Regions the individual has visited
• To minimize cheating, the score factors in user
behavior, e.g. that they haven't turned the
phone off
SafetyScore Calculation
SafetyScore
1st
, 2nd
Degree
Risk Exposure
Geo-Region
Activity Profile Risk Profile
Test Results
(Immunity,
Negative Tests)
18. • Most contact tracing apps have seen adoption
rates of less than 20% — resulting in less than
4% of contacts being traced
• In contrast, the SafetyScore health passport is
able to work effectively at the local community
level, and can thus grow to scale organically
• The ability to safeguard spaces aligns with the
operational and liability concerns of universities
and businesses, further accelerating adoption
Designed for Growth
19. • SafetyScore has been designed from the
ground up to maximize a user's privacy and to
protect them from being tracked
• User activity is obscured through multiple
cryptographic layers and constantly changes so
as to limit the potential for mass surveillance
• SafetyScore builds on established primitives
such as cryptographic blinding to obscure the
social interactions between people
Privacy First
20. • SafetyScore nodes act as an API server for
clients like mobile apps. Collectively, these
nodes form a peer-to-peer network
• Since they are not controlled by a single entity,
it protects the system from malicious parties
such as foreign agents
• While we expect governments to run nodes to
serve their population, anyone will be able to
run one to further improve network security
Decentralized Protocol
Distribution
Commitments
Risk
Account
Day 7
Notary1
Notary2
Notary3
A305
B305
B305 B306
C306 D306 E306
B307
1
2
3
4
7
6
5
21. • SafetyScore is built around a distributed ledger
which serves as a high-integrity, shared
database without a single point of control
• Our distributed consensus algorithm is able to
scale to meet the high throughput needs of
SafetyScore
• To protect against resource exhaustion attacks
and spam, nodes will only gain the right to
write to the ledger by acting reliably over time
Distributed Ledger
Signature for Block 5 Signature for Block 6
Block
Reference
Block
Reference
Block
Reference
Block
Reference
Block
Reference
Entry Entry Entry Entry Entry
Entry Entry
Entry Entry Entry Entry Entry
Entry Entry Entry Entry Entry
22. • When health officials certify infections, they
make public some anonymized data, e.g. type
of disease, test method, location, etc.
• Epidemiologists can use this to track disease
spread and can act as an early warning system
for new infectious diseases
• Health authorities can use this to prioritize
resource allocation and co-ordinate responses
both locally and globally
Epidemic Response Hub
23. • SafetyScore is being developed as an open
source project. This helps us maximize
transparency and build a global community
• The SafetyScore protocol will be an open
standard so that others can build on it, e.g.
hardware devices, software services, etc.
• We will also release an extensible mobile SDK
so that others can integrate SafetyScore into
their existing apps and services
Open Source
24. • SafetyScore’s protocol is flexible enough to
address all contagious diseases, whether it's
the seasonal flu or a new pandemic
• It can be continuously updated to address new
scientific data, e.g. new strains, new diseases,
our understanding of immunity, etc.
• SafetyScore can self-learn and adapt the score
calculation to changes in disease transmission
and social behavior
Future Proof
25. • SafetyScore primarily accounts for
transmission via people and is limited in its
ability to track transmission via surfaces
• While smartphone adoption is high enough in
urban areas, where most transmission happens,
it might be an issue in certain countries
• SafetyScore will use about 30MB of mobile
data every day. This may prove to be costly for
users in some countries
Limitations
26. • The targeted approach of health passports
might feel unfair, but we believe this is better
than blanket lockdowns
• Governments will be able to help ensure fairness
by making special allowances for key workers,
vulnerable citizens, and essential services
• SafetyScore will make visible to users the
various factors that are affecting their score so
as to maximize transparency and trust
Fairness
29. Assembled from World-Leading Experts
✓ Public Health
✓ Epidemiology
✓ Privacy
✓ Cybersecurity
✓ Distributed Systems
✓ Open Source
✓ Human-Centered Design
30. Tav Siva Social entrepreneur,
distributed systems engineer, open
source developer. Chainspace, UK
Home Office, WikiHouse, Freenet
Tom Salfield Social-tech
entrepreneur, collaborative systems
designer. Wikifactory, Impact Hub,
Opencoin, Imperial, LSE
Dr. Luke Robinson Deep tech
entrepreneur, quantum physicist.
Post Urban Ventures, Hazy, Oxford,
Cambridge
Dr. Oliver Zahn Ex-Head of Data
Science at Google. Tech
entrepreneur. SpaceX, Impossible
Foods, UC Berkeley, Harvard
Dr. Laura Kahn Co-founder at One
Health Initiative. Public health
expert, physician, science and
global security scholar. Princeton
Dr. David Spergel Director at
Simons Foundation. Computational
astrophysicist. Breakthrough prize
winner. Princeton, NASA, Harvard
Imtiaz Shams AI entrepreneur,
non-profit builder, fundraising. Post
Urban Ventures, Charities: Think &
Faith to Faithless, LSE
Alice Fung Director at Health
Foundry. Top 100 Women in Social
Enterprise. Architecture 00, Mayor's
Design Advocate, Impact Hub
Hinesh Mandalia Senior full-stack
engineer, fintech. G-Research,
Lloyds Banking Group, Logica,
Imperial
William Pritchard Senior QA
engineer, automation tester, data
security, AI. Genomics England, UK
Cabinet Office, Capgemini
Krishna Kotecha Ex-iOS team lead
at Babylon Health. Award-winning
mobile developer. Hailo, Deutsche
Bank, Symbian
Ramesh Nair Full-stack polyglot
engineer, blockchain enthusiast.
Nayms, TokenCard, Ethereum
Foundation, Imperial
Alex McKinlay Senior software
engineer, distributed systems, fintech,
smart contracts. Refinitiv, TokenCard,
Pantheon Ventures
Huy Dinh Experienced CTO, scalable
systems architect, app developer.
NTT Docomo. Guardian News, BBC
Worldwide
Dr. Nina Fefferman Infectious
diseases modeling expert. Professor
in Ecology, Evolution & Maths at UT
Knoxville. Rutgers, Tufts, Princeton
Anthony Leung Senior finance,
treasury, and strategy executive.
Tesco, Credit Suisse, Morgan
Stanley, LSE
Seyi Ogunyemi Senior full-stack
engineer, graphic designer, UX
specialist, fintech. Civic, Espians,
Coca-Cola, Diageo
42. Establishing Contact Keys
Save Contact
Key from X
Save Contact
Key from Y
Broadcast
Key
Broadcast
Key
X
Y
Derive Shared Secret
Derive Temporary
Contact Key for Y
Derive Temporary
Contact Key for X
Distributed Ledger
Post Contact
Proof to Ledger
Post Contact
Proof to Ledger
Post Contact
Key for Y
Post Contact
Key for X
Aggregate proofs from X
corresponding to the same
Activity Period
Aggregate proofs from Y
corresponding to the same
Activity Period
47. Risk Distribution Tree
A6
B6 C6 D6
F10 F12 G12
H10 I12 J12
Distribution
Implicit Distribution
Activity Key
Legend:
C11B8 B9 D12
F11F9E8
J7
Connection
48. Links
1. Bidirectional Contact Tracing is Required for Reliable COVID-19 Control
2. The UK's Contact Tracing Plan Has Two Fatal Flaws
3. Effective Configurations of a Digital Contact Tracing App: A report to NHSX
4. Contact-Tracing Apps Aren’t the Technology Panacea People Hoped
5. Exposure Notifications: Using Technology to Help Public Health Authorities Fight COVID-19
6. A Socio-Technical Framework for Digital Contact Tracing
7. Longitudinal Evaluation and Decline of Antibody Responses in SARS-CoV-2 Infection
