A
verifiable
claim
is
a
qualification,
achievement,
quality,
or
piece
of
information
about
an
entity's
background
such
as
a
name,
government
ID,
payment
provider,
home
address,
or
university
degree.
Such
a
claim
describes
a
quality
or
qualities,
property
or
properties
of
an
entity
which
establish
its
existence
and
uniqueness.
The
use
cases
outlined
here
are
provided
in
order
to
make
progress
toward
possible
future
standardization
and
interoperability
of
both
low-
and
high-stakes
claims
with
the
goals
of
storing,
transmitting,
and
receiving
digitally
verifiable
proof
of
attributes
such
as
qualifications
and
achievements.
The
use
cases
in
this
document
focus
on
concrete
scenarios
that
the
technology
defined
by
the
group
should
address.
Status
of
This
Document
This
is
a
preview
Do
not
attempt
to
implement
this
version
of
the
specification.
Do
not
reference
this
version
as
authoritative
in
any
way.
Instead,
see
https://w3c.github.io/vc-use-cases/
for
the
Editor's
draft.
This
section
describes
the
status
of
this
document
at
the
time
of
its
publication.
A
list
of
current
W3C
publications
and
the
latest
revision
of
this
technical
report
can
be
found
in
the
W3C
technical
reports
standards
and
drafts
index
at
https://www.w3.org/TR/.
This
document
represents
a
concise
but
limited
collection
of
use
cases
readers
should
review
alongside
the
Verifiable
Credentials
Data
Model
.
The
work
on
this
document
was
carried
out
under
tight
time
constraints
due
to
limitations
of
the
W3C
process
and
publishing
deadlines.
Under
such
conditions,
errors
are
unavoidable
and
some
of
the
ideas
presented
here
are
incomplete.
The
Working
Group
hopes
that
in
the
future,
W3C
process
can
be
revised
to
better
support
the
dynamic
nature
of
standards
work
in
a
more
consistent
way
across
different
groups.
Publication
as
an
Editor's
Draft
does
not
imply
endorsement
by
W3C
and
its
Members.
This
is
a
draft
document
and
may
be
updated,
replaced
or
obsoleted
by
other
documents
at
any
time.
It
is
inappropriate
to
cite
this
document
as
other
than
work
in
progress.
The
Verifiable
Claims
Working
Group
at
the
W3C
is
developing
standards
for
expressing
and
exchanging
"
claims
"
that
have
been
verified
by
a
third
party
and
to
make
them
easier
and
more
secure
on
the
Web.
Note
This
document
does
NOT
attempt
to
define
an
architecture
for
the
support
of
Verifiable
Claims.
Instead
it
expresses
the
sorts
of
needs
that
real
users
have
that
could
be
addressed
through
support
for
some
sort
of
self-sovereign
claim
environment.
It
attempts
to
use
terminology
that
is
consistent
with
the
other
deliverables
of
the
Verifiable
Claims
Working
Group
(you
can
see
the
relevant
terms
in
Appendix
A).
1.1
Importance
of
this
work
Entities
(people,
organizations,
devices)
need
to
make
many
kinds
of
claims
as
part
of
their
everyday
activities.
As
more
and
more
of
these
important
activities
move
to
the
Internet,
entities
need
to
be
able
to
transmit
instantly
verifiable
claims
(e.g.,
about
their
location,
accomplishments,
value,
what-have-you).
From
educational
records
to
payment
account
access,
the
next
generation
of
web
applications
will
authorize
entities
to
perform
actions
based
on
rich
sets
of
credentials
issued
by
trusted
parties.
Human-
and
machine-mediated
decisions
about
job
applications,
account
access,
collaboration,
and
professional
development
will
depend
on
filtering
and
analyzing
growing
amounts
of
data.
It
is
essential
that
data
be
verifiable.
Standardization
of
digital
claim
technologies
makes
it
possible
for
many
stakeholders
to
issue,
earn,
and
trust
these
essential
records
about
their
counterparties,
without
being
locked
into
proprietary
platforms.
1.2
Use
case
model
This
document
presents
an
aggregate
use
case
model,
composed
of
Needs,
Roles,
Tasks,
and
Sequences.
Taken
together,
these
models
define
the
use
cases
that
the
Verifiable
Claims
Working
Group
has
addressed.
User
needs
define
the
problem
space
addressed
by
verifiable
credentials
.
User
Roles
specify
the
roles
different
entities
play
when
interacting
with
verifiable
credentials
.
Tasks
define
the
functions
users
can
accomplish,
and
sequences
demonstrate
how
tasks
might
be
realized,
by
interactions
between
entities
over
time.
As
with
all
models,
this
use
case
model
is
neither
exhaustive
nor
complete.
The
listed
uses
cannot
capture
all
possible
use
cases.
Similarly,
the
models
do
not
completely
characterize
the
use
cases
represented.
However,
the
combined
model
is
intended
to
provide
specific,
coherent
guidance
for
the
work
ahead.
1.3
Conformance
As
well
as
sections
marked
as
non-normative,
all
authoring
guidelines,
diagrams,
examples,
and
notes
in
this
specification
are
non-normative.
Everything
else
in
this
specification
is
normative.
The
key
word
MUST
in
this
document
is
to
be
interpreted
as
described
in
BCP
14
[
RFC2119
]
[
RFC8174
]
when,
and
only
when,
they
appear
in
all
capitals,
as
shown
here.
Figure
2
Verifiable
Credentials,
Example
Domains
for
User
Needs
3.1
Education
The
education
domain
includes
all
levels
of
the
educational
experience;
from
primary
through
professional
continuing
education.
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E.1
Digital
transcript
Joleene
is
the
registrar
of
Mega
University
and,
by
virtue
of
her
office,
is
responsible
for
the
integrity,
accuracy,
and
security
of
academic
records.
Joleen
has
been
a
pioneering
registrar
in
advocating
an
"extended
transcript"
that
includes
not
only
the
standard
set
of
course
grades
but
also
adds
supplementary
information
on
learner
competencies.
These
might
include
work
experiences
and
non-educational
but
marketable
skills.
Upon
the
request
of
her
students,
Joleen
issues
a
digital
credential
that
includes
an
extended
transcript.
E.2
Taking
a
test
Eunice
is
about
to
take
her
ACT
(a
test
used
to
evaluate
her
readiness
for
college).
When
she
arrives
at
the
testing
center,
she
is
required
to
present
identification.
Her
government-issued
identity
certificate
is
acceptable,
as
the
verifiable
credentials
contained
in
it
reflect
all
of
the
required
attributes
and
it
is
difficult
to
counterfeit.
E.3
Transferring
schools
Rocky
is
an
undergraduate
student
at
Wossamotta
U.
His
school
provides
a
credential
repository
service
to
all
students
and
alumni,
so
he
chooses
to
use
it.
In
his
third
year,
Rocky
decides
to
transfer
to
Moosylvania
Tech.
They
do
not
offer
a
service,
but
he
does
not
want
to
continue
to
use
the
service
of
his
old
(and
now
rival
school)
so
he
moves
his
claims
to
the
service
offered
by
his
bank
without
needing
to
have
them
reissued.
E.4
Online
classes
In
MOOC
and
other
online
learning
systems,
being
able
to
reliably
identify
participants
is
vital
to
ensure
the
individual
evaluation
and
certification.
Nick
is
participating
in
a
course
online
and
takes
a
test.
He
is
required
to
provide
his
credentials
to
prove
his
identity
before
the
test,
and
then
to
allow
the
system
to
issue
a
verifiable
credential
regarding
the
results
of
his
test.
3.2
Retail
The
retail
domain
encompasses
all
things
where
there
is
an
exchange
of
value
on
an
individual
level.
This
includes
brick-and-mortar
store
fronts,
web-only
venues,
and
even
person-to-person
sales.
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R.1
Address
verification
Francis
has
found
the
perfect
pair
of
shoes.
When
processing
orders,
Giant
Shoe
Company
wants
to
be
certain
that
his
shipping
address
is
accurate
(inaccurate
addresses
are
very
expensive
in
terms
of
customer
service).
They
offer
a
discount
for
customers
who
make
verifiable
addresses
available
as
part
of
the
checkout
process.
Francis
offers
his
certificate
and
gets
the
perfect
shoes
for
even
less
than
he
expected.
R.2
Adult
beverages
June
goes
to
her
local
beer
and
wine
store
to
buy
a
bottle
of
wine.
She
submits
her
identity
credential
that
lets
the
liquor
store
owner
know
that
she
is
over
21
without
having
to
reveal
her
actual
date
of
birth,
her
address,
or
her
state
ID
number.
R.3
Fraud
detection
On
a
bright
Sunday,
Oskar
remembers
that
he
still
needs
to
buy
his
wife
a
precious
gift
for
their
wedding
anniversary.
However,
he
is
acutely
aware
that
it
is
precisely
in
weekends
that
gangs
set
up
fraudulent
web
shops
that
claim
to
sell
such
gifts,
while
in
fact
they
only
take
the
cash,
and
disappear
on
Mondays.
So
before
actually
purchasing
a
gift
from
the
web
shop
of
his
choice,
he
requests
the
shop
to
provide
a
credential
issued
by
the
chamber
of
commerce,
that
contains
proof
of
legitimacy.
After
having
verified
that
the
shop
is
legit,
he
can
purchase
his
gift.
R.4
Bona-fide
shopper
David
owns
a
restaurant
and
has
registered
with
a
low
cost
wholesaler
to
purchase
provisions
in
bulk.
The
wholesaler
has
issued
a
credential
to
David,
to
prove
that
he
is
entitled
to
enter
the
warehouse
in
order
to
purchase
goods
that
are
not
available
to
the
general
public.
The
credential
is
marked
"non-transferable"
to
stop
David
passing
the
credential
to
his
friends
to
allow
them
to
purchase
low
cost
provisions.
3.3
Finance
The
Finance
domain
includes
banking,
brokerage,
insurance,
and
other
industries
where
there
is
a
high
value
placed
on
knowing
exactly
with
whom
you
are
dealing.
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F.1
Reuse
know
your
customer
Jane
is
opening
an
account
at
MidBank
in
Finland.
As
part
of
that
process,
the
bank
asks
her
to
provide
two
from
a
variety
of
possible
sources
to
confirm
her
identity
—
a
so-called
"Know
Your
Customer"
check.
She
selects
government-supplied
verifiable
credentials
that
confirm
she
receives
postal
mail
at
a
certain
address
and
that
she
has
a
national
ID
card.
Confirming
these
allows
the
bank
to
open
her
account
and
be
confident
in
her
identity
when
she
conducts
transactions.
Now
that
the
account
is
open,
Jane
is
issued
a
digitally-signed
credential
for
her
checking
account
at
MidBank.
This
credential
verifies
that
Jane
has
an
account
at
MidBank
and
has
access
to
her
associated
checking
account.
It
is
issued
to
a
controlled
identifier
over
which
Jane
has
demonstrated
proof-of-control.
When
presented,
Jane
again
demonstrates
proof-of-control
over
that
identifier
to
give
the
verifier
confidence
that
the
current
holder
presenting
the
credential,
is
in
fact,
the
original
recipient
of
the
credential.
Since
MidBank
(and
all
banks
in
Finland)
are
required
to
perform
"Know
Your
Customer"
checks
on
accounts,
this
credential
can
also
be
treated
as
sufficient
verification
by
other
financial
institutions.
This
helps
Jane
assure
destination
banks
that
she
is
verified,
thereby
allaying
concerns
about
misdirected
transactions
and
money
laundering.
F.2
Money
transfer
Susan
wants
to
send
funds
to
her
family
in
another
country
via
a
popular
money
transfer
service.
She
has
verifiable
credentials
in
her
credential
repository
that
can
be
used
to
share
her
identity
profile.
She
has
also
been
sent
a
credential
from
her
family
verifying
their
banking
information.
By
sharing
these
with
the
money
transfer
service,
they
can
automatically
verify
the
source
and
destination
of
funds,
thus
being
confident
in
the
delivery
of
those
funds
and
satisfying
various
regulations
regarding
prevention
of
money
laundering.
F.3
Closing
account
John
opens
a
checking
account
at
Big
Bank
Co
and
is
issued
a
verifiable
credential
indicating
that
the
account
exists,
that
the
bank
verified
John's
identity,
and
that
John
has
access
to
the
account.
Some
time
later,
John
is
moving
to
a
new
city
and
decides
to
close
that
account.
Big
Bank
Co
needs
to
revoke
that
claim
as
part
of
their
normal
account
closing
process.
F.4
Trying
out
a
new
service
Nikita
has
several
accounts
with
BigBank,
as
well
as
a
brokerage
account
with
WallStreetCo.
She
had
placed
all
of
her
claims
in
a
credential
repository
at
BigBank
that
came
free
when
she
opened
her
accounts.
WallStreetCo
is
now
offering
a
new
repository
that
has
an
interface
she
thinks
she
will
prefer.
Nikita
copies
her
claims
from
BigBank
into
the
repository
at
WallStreetCo
to
experiment
with
their
service,
but
continues
to
use
the
service
from
BigBank
while
she
is
testing.
F.5
New
bank
account
from
home
Alice
wants
to
open
a
new
bank
account.
BigOnlineBank
offers
the
ability
to
do
this
from
home
if
she
can
provide
electronic
credentials.
She
offers
government-issued
certificates
that
verify
her
identity
(address,
national
identity
number,
etc.),
and
opens
her
new
account
from
her
couch.
3.4
Healthcare
Privacy
is
critically
important
in
the
healthcare
industry.
This
domain
looks
at
everything
from
physical
interaction
to
connecting
patients
and
providers
with
service
organizations.
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H.1
Prescribing
Barney
is
a
physician,
and
has
recently
become
board
certified
in
his
state.
The
state's
board
issues
Barney
a
digital
certificate
confirming
that
he
is
certified
to
practice
medicine
in
that
state.
Barney
can
now
use
this
certificate
when
writing
prescriptions
and
referrals,
thereby
improving
accountability
and
verifiability.
H.2
Online
pharmacy
iPharmacy
receives
a
prescription
for
Bob
electronically
from
a
local
clinic.
It
includes
a
certificate
about
the
physician
that
issued
the
prescription
as
well
as
one
about
Bob.
iPharmacy's
system
automatically
verifies
the
ability
of
the
physician
to
write
prescriptions,
as
well
as
Bob's
insurance
coverage.
When
Bob
arrives
to
pick
up
his
medication,
iPharmacy
further
correlates
his
identity
with
the
certificate,
thereby
improving
the
end-to-end
accountability
of
their
system.
H.3
Insurance
claim
Tracy
has
a
sore
throat
soon
after
moving
to
a
new
town.
She
finds
a
physician
through
her
health
care
network
and
goes
in
for
treatment.
She
is
a
new
patient,
so
the
clinic
needs
to
know
who
she
is
and
how
she
will
be
paying.
When
checking
in,
she
presents
her
verifiable
credential
that
demonstrates
her
identity
and
her
proof
of
insurance.
When
the
clinic
submits
this
to
the
insurance
company,
they
can
automatically
ascertain
that
she
submitted
her
proof
of
identity
and
insurance
to
the
provider
and
granted
the
physician
the
ability
to
submit
the
claim
for
payment.
H.4
Traveling
illness
John
is
on
the
vacation
of
a
lifetime,
travelling
the
world.
Falling
ill,
he
visits
a
health
clinic
in
a
country
in
which
he
does
not
live.
At
the
clinic,
he
is
asked
for
proof
of
identity.
He
provides
a
credential
that
verifies
his
name
and
address,
but
elects
not
to
disclose
his
marital
status
nor
his
social
security
number,
as
those
are
neither
requested
nor
required
at
this
clinic.
He
further
marks
the
disclosure
as
expiring
in
30
days—he
does
not
want
his
information
verifiable
after
that
time.
H.5
Proving
Legal
Disability
Status
Trina,
who
is
legally
blind,
is
currently
unemployed,
and
needs
to
use
the
local
free
disability
ride
service
to
get
to
the
employment
office.
To
use
this
service,
she
is
required
to
verify
that
she
maintains
legal
disability
status.
Trina
provides
her
government-issued
disability
credential
to
sign
up
for
the
ride
service,
and
is
not
required
to
disclose
her
specific
disability
to
the
ride
service,
as
this
could
put
her
at
personal
risk.
3.5
Professional
Credentials
In
many
aspects
of
life
it
is
important
to
know
that
entities
are
who
they
say
they
are,
and
that
they
can
do
what
they
say.
Professional
accreditation
is
one
way
of
learning
about
the
abilities
of
an
entity
.
Being
able
to
verify
these
credentials
is
essential
to
their
value.
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C.1
Find
a
doctor
Jason
is
looking
for
a
new
primary
care
physician.
His
health
provider
includes
information
on
their
web
site
about
the
physicians
they
have
on
staff,
including
verifiable
credentials
about
their
education,
board
certification,
and
continuing
education.
Jason
can
verify
these
credentials
and
be
confident
that
his
new
physician
satisfies
his
requirements.
C.2
Busy
doctor
Barney
was
a
board-certified
physician,
but
he
ran
out
of
time
to
complete
his
continuing
education
requirements
and
his
certification
lapsed.
Since
the
board
can
revoke
his
certification,
credential
verifiers
will
automatically
be
aware
that
he
can
no
longer
issue
prescriptions
or
perform
medical
procedures.
C.3
Bad
university
Jane
was
issued
a
certificate
by
BigTraining
Co.,
indicating
that
she
was
a
trained
Project
Manager.
It
was
later
discovered
that
BigTraining
Co.
was
not
actually
training
anyone,
and
their
organization's
certificate
was
revoked
via
the
US
Department
of
Education's
Accreditation
Database.
Jane's
credential
is
therefore
invalid,
and
prospective
employers
will
be
aware
of
this
when
they
check
her
certifications.
C.4
New
employer
Jessica
is
a
medical
doctor
practicing
in
the
United
States.
She
has
a
variety
of
digital
claims
that
explain
her
qualifications,
schooling,
continuing
education
achievements,
and
board
certifications.
These
are
all
stored
in
the
credential
repository
provided
by
her
employer.
When
she
is
offered
a
position
with
another
health
provider
network,
she
can
automatically
transfer
all
of
these
claims
to
her
new
employer.
C.5
Social
authority
Josie
is
a
healthcare
worker
that
has
created
a
profile
on
a
professional
social
network
to
make
herself
readily
available
for
new
opportunities
in
the
workforce.
She
lists
her
employment
history
and
credentials
including
degrees,
certificates,
and
digital
badges.
The
website
requests
verification
of
her
credential
claims
in
order
for
her
credentials
to
be
visible
when
she
posts
messages.
Josie
authorizes
the
sharing
of
the
relevant
claims
with
the
website,
and
the
site
verifies
them
before
allowing
Josie
to
expose
them.
"Freedom?"
is
an
online
forum
that
encourages
free
discussion
about
issues
controversial
in
Freedonia.
The
forum
allows
users
to
register
anonymous
accounts,
but
it
also
allows
users
to
obtain
badges
based
upon
real-world
certifications.
Paula
has
been
certified
as
an
aid
worker,
and
wishes
that
information
to
be
marked
on
her
posts.
She
shares
her
certificate
with
the
forum,
but
limits
it
to
only
verifying
that
she
is
the
holder
of
the
certificate,
that
she
is
the
subject
of
it,
and
that
she
is
an
aid
worker.
In
this
way
she
maintains
her
anonymity
in
this
controversial
forum
while
still
being
able
to
assist
her
fellow
countrymen.
C.6
Job
applicant
Software
Co.
has
posted
an
open
position
online
and
they
are
receiving
thousands
of
applications.
Cindy
has
applied
for
the
job.
Unlike
many
applicants,
she
has
attached
her
education
credentials—college
degree,
additional
specific
software
training,
etc.
Software
Co.
evaluates
these
credentials
automatically
as
they
receive
her
application.
Because
her
materials
are
verifiable
and
verified,
her
application
is
immediately
forwarded
as
a
viable
candidate.
3.6
Legal
Identity
For
many
transactions,
an
entity
must
be
able
to
prove
some
aspect
of
their
identity
in
a
way
that
can
be
quickly
verified.
Governments
and
other
widely
recognized
entities
are
well
positioned
to
provide
such
identification
in
a
verifiable
digital
form.
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L.1
Digital
driving
license
Asako
just
passed
the
final
test
to
receive
a
drivers
license.
As
she
is
still
a
new
driver,
and
may
be
pulled
over
for
a
traffic
violation,
she
would
like
to
receive
a
credential
that
asserts
a
claim
that
she
has
right
to
drive
a
car.
She
requests
a
credential
from
the
certifying
authority
(
issuer
)
that
she
can
use
to
prove
to
the
officer
(
credential
verifier
)
that
her
claim
is
valid.
L.2
Seamless
immigration
Tom
is
a
frequent
international
traveler.
In
order
to
speed
processing
through
immigration
check
points,
he
applies
for
a
digital
passport
from
his
governmental
authority.
After
satisfying
background
check
requirements,
the
authority
issues
Tom
an
electronic
version
of
his
passport.
This
version
is
verifiable
and
retains
a
history
of
all
the
places
he
visits
so
that
immigration
officials
can
quickly
and
easily
evaluate
his
suitability
as
a
visitor
to
their
country.
Once
they
are
satisfied,
they
will
automatically
add
the
details
of
this
new
visit
to
Tom's
passport.
L.3
Speedy
air
travel
Security
for
air
travel
is
more
and
more
rigorous,
requiring
more
and
more
time
to
validate
each
passenger.
Ivan
has
a
collection
of
verifiable
credentials
that
are
assembled
into
his
air
travel
Identity
Profile
.
When
Ivan
needs
to
pass
through
a
security
checkpoint
at
his
airport,
he
presents
this
profile
before
entering
the
line.
Because
his
identification
can
be
immediately
and
automatically
verified,
he
is
permitted
to
skip
the
long
line
and
go
straight
to
the
metal
detector.
L.4
Refugee
crisis
Thousands
of
people
each
year
are
displaced
because
of
man-made
and
natural
disasters.
Anoushka
is
one
such,
having
been
forced
to
flee
her
village
along
with
her
mother
and
younger
brother.
They
reach
an
IFRC
center
just
across
the
border
in
a
relatively
safe
area,
but
with
no
documentation.
Since
the
government
of
her
homeland
is
in
turmoil,
there
is
no
way
for
the
IFRC
staff
to
easily
establish
their
identities.
Fortunately,
Anoushka
had
been
issued
a
self-sovereign
proof
of
birth,
attached
to
which
is
the
proof
of
birth
and
marriage
for
her
parents.
She
is
able
to
retrieve
this
because
it
is
available
from
many
places
often
the
Internet.
Since
it
is
verifiable,
the
IFRC
is
comfortable
vouching
for
them
and
resettling
them
in
a
safer
area
for
the
duration
of
the
conflict.
3.7
Devices
Intelligence
devices
are
created
and
deployed
so
that
they
can
interact
with
other
entities
(people,
organizations,
devices).
Establishing
trust
and
maintaining
secure
relationships
with
these
devices
is
especially
critical.
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D.1
Devices
during
manufacturing
Bob,
the
director
of
production
at
HVAC
Manufacturing,
issues
a
device-identifying
verifiable
credential
(e.g.
IDevID,
IAK)
at
the
factory
for
an
energy-saving
fan
controller
IoT
device.
Carol,
senior
quality
engineer
at
Certifications
Testing
Lab,
issues
a
certification
of
specification-compliance
verifiable
credential
to
the
fan-controller
device
at
the
certification
lab
during
the
manufacturing
process.
When
the
fan
controller
is
installed
at
the
customer's
office
at
Modern
Office
Spaces,
the
controller's
identifying
credential
can
be
verified
by
Sam,
IT
technician,
to
establish
the
identity
of
the
controller
as
part
of
the
on-boarding
of
the
new
controller.
The
controller's
specification-compliance
credential
is
verified
to
demonstrate
the
controller's
Energy-Star
compliance.
D.2
Devices
during
delivery
As
the
fan
controller
leaves
the
factory,
additional
verifiable
credentials
are
issued
by
Vince,
a
systems
engineer
at
VAR
Resellers,
as
he
verifies
the
manufacturer's
configuration
matches
the
verifiable
credentials
accompanying
the
device.
He
then
installs
a
software
package
specific
to
Modern
Office
Spaces
needs
and
issues
verifiable
credentials
that
establish
evidence
of
possession
by
VAR
Resellers
and
the
software
additions
Vince
made
to
the
device.
Finally,
upon
delivery
to
Sam,
the
end
customer,
the
verifiable
credentials
show
that
the
fan
controller
has
been
securely
handled
and
contains
the
correct
features
and
certifications.
D.3
Devices
setup
for
operating
autonomously
Sam,
the
new
device
owner,
needs
to
trust
the
device
originated
from
HVAC
Manufacturing
and
was
handled
correctly
at
Certifications
Testing
Lab
and
installed
with
the
correct
software
package
at
VAR
Resellers.
After
Sam
verifies
each
of
the
verifiable
credentials
,
he
issues
another
verifiable
credential
for
fan
controller
#37
which
includes
assertions
relating
to
trust:
device
manufacturer
model/version,
software
manufacturer
model/version,
security
versions
of
components
TCB,
and
associated
devices
the
fan
controller
is
authorized
to
interact
with
including
thermostat-board-room.
The
thermostat-board-room
monitors
room
temperature.
When
the
temperature
is
too
hot
it
switches
the
fan
controller
#37
on
and
later
when
the
temperature
reaches
a
comfortable
level,
off.
The
device
makes
sure
the
control
signals
from
thermostat-board-room
are
authorized
(namely,
that
Sam
intended
for
thermostat-board-room
to
control
the
fan
controller).
Sam
is
concerned
about
the
security
of
the
smart
board
room.
He
configures
the
autonomously
interacting
devices
to
re-verify
device
trustworthiness
attributes
periodically
by
re-checking
that
the
device
originated
from
HVAC
Manufacturing
and
was
handled
correctly
by
Certifications
Testing
Lab
and
installed
with
the
correct
software
package
by
VAR
Resellers.
Sam
may
update
the
device’s
software
occasionally
during
its
lifetime.
Even
though
Sam
is
applying
the
update,
VAR
Resellers
supplies
the
correct
update.
The
device
ensures
that
only
VAR
Resellers
is
able
to
supply
the
updated
software
image
and
that
only
Sam
is
able
to
apply
the
update.
4.
User
Tasks
Use
cases
are
often
used
as
a
driver
for
requirements.
While
the
users
of
verifiable
credentials
have
needs
across
many
domains,
the
tasks
associated
with
those
needs
span
the
domains.
This
section
summarizes
those
tasks,
as
well
as
requirements
related
to
the
tasks,
and
maps
the
tasks
and
requirements
back
to
the
associated
needs.
Note
It
is
worth
noting
that
the
subject
may
or
may
not
be
the
same
entity
as
the
holder
.
There
are
no
tasks
in
these
examples
that
require
participation
of
the
subject
.
Individuals
and
organizations
need
a
way
to
issue
claims
about
themselves
or
others
that
can
be
verified
and
trusted.
Needs
F.1
,
E.1
,
L.1
,
H.1
4.2
Assert
Claim
Requirement
It
MUST
be
possible
for
the
holder
of
a
verifiable
credential
to
restrict
the
amount
of
information
exposed
in
a
credential
they
choose
to
share.
It
also
MUST
be
possible
for
the
holder
to
limit
the
duration
for
which
that
information
is
shared.
Motivations
Credentials
may
be
issued
about
a
subject
that
include
multiple
attributes,
only
some
of
which
are
required
when
verifying
a
specific
criteria
is
satisfied.
The
holder
should
have
the
ability
to
satisfy
the
criteria
without
revealing
additional
attributes
that
are
not
required.
Needs
R.2
,
H.4
4.3
Verify
Credential
Requirement
It
is
expected
to
be
possible
for
a
verifier
to
verify
that
the
credential
is
an
authentic
statement
of
an
issuer's
claims
about
the
subject
.
Verifiers
MUST
have
the
capability
to
cryptographically
prove
that
a
credential
has
not
been
tampered
with
since
issuance
(authenticity)
and
that
the
issuer
continues
to
assert
the
claims
as
true
(currency).
To
check
authenticity,
the
issuer's
verification
method(s),
such
as
a
public
key,
must
be
discoverable
from
the
credential
itself.
It
is
expected
that
the
issuer
identifier
either
is
itself
cryptographically
verifiable,
or
that
it
can
be
used
to
reliably
discover
the
cryptographic
material
necessary
to
confirm
that
the
content
of
a
credential
has
not
been
changed
since
issuance.
It
is
understood
that
verification
depends
on
the
verifier's
acceptance
of
the
robustness
of
the
cryptographic
mechanisms
used
for
testing
authenticity
and
for
discovering
verification
methods.
An
untrusted
verification
method
cannot
be
relied
upon
for
verification.
Verifiers
must
also
be
able
to
inquire
about
the
current
status
of
a
credential
without
revealing
to
the
issuer
The
entity
requesting
that
status
The
credential
for
which
status
is
being
checked
The
subject
of
the
credential
being
checked
Requiring
that
verifiers
perform
this
status
check
is
what
enables
issuers
to
revoke,
suspend,
or
otherwise
moderate
the
status
of
the
credential.
Similarly,
if
a
discovery
mechanism
is
used
to
retrieve
verification
methods
for
a
given
issuer,
verifiers
must
be
able
to
do
so
without
revealing
unnecessary
information
to
the
issuer.
In
short,
it
must
be
possible
to
fully
verify
a
credential
without
leaking
usage
data
to
the
issuer
or
anyone
else.
This
is
to
avoid
the
so-called
"phone
home"
problem.
Motivations
In
many
environments
(such
as
order
processing),
information
—
such
as
a
payer's
address,
citizenship,
or
age
—
needs
to
be
automatically
verified
to
complete
the
transaction.
It
MUST
be
possible
to
verify
these
in
an
automated
fashion.
Needs
F.2
,
C.1
,
E.2
,
R.1
,
F.5
,
H.2
,
C.6
4.4
Validate
Claim
Requirement
It
MUST
be
possible
for
a
verifier
to
check
whether
a
given
claim
is
appropriate
for
a
particular
use.
That
is,
given
a
credential
that
is
authentic
and
current,
the
verifier
needs
to
interpret
the
claims
in
the
context
of
their
own
'business
rules'
concerning,
for
instance,
which
parties
are
acceptable
authorities,
and
which
cryptographic
mechanisms
are
acceptable
for
what
situations.
Is
the
issuer
someone
we
know?
Are
the
claims
made
by
this
issuer
appropriate
for
this
particular
issuer's
authority?
Is
the
holder's
presentation
an
appropriate
use
of
the
credential?
The
first
and
second
questions
will
be
answered
because
either
the
verifier
already
knows
the
public
identifiers
for
the
issuers
it
recognizes
for
specific
claims,
or
there
is
a
discovery
mechanism
whereby
verifiers
can
find
appropriate
issuers
given
their
business
requirements.
The
business
rules
may
allow
the
use
of
certain
credentials
for
specific
situations,
even
when
verification
fails.
For
example,
a
suspended
or
expired
professional
license
may
be
accepted
by
an
employer
as
evidence
of
past
experience
without
it
being
treated
as
a
current
qualification
for
roles
that
require
that
license.
For
this
reason,
current
status
(as
part
of
verification)
only
deals
with
the
status
of
the
credential
as
maintained
by
the
Issuer.
Timeliness
is
the
domain
of
validation.
It's
important
to
note
that
the
bounds
of
authority
for
a
given
issuer
are
specific
claim
types
made
by
them
and
relied
upon
by
others.
While
a
region's
DMV
(Department
of
Motor
Vehicles)
or
equivalent
agency
might
be
an
acceptable
authority
for
an
individual's
driving
privilege,
it
should
probably
not
be
treated
as
authoritative
for
an
individual's
hair
color
or
current
address,
even
though
DMVs
regularly
include
such
claims
in
today's
driver's
licenses.
Unlike
verification,
it
may
not
always
be
possible
to
automate
validation.
Some
use
cases
require
human
review
before
accepting
a
particular
credential
for
a
particular
use.
For
example,
a
digital
proof
of
age
system
might
need
a
trusted
human
agent
to
visually
compare
the
holder/presenter
in
real-space
to
a
reference
photo
securely
referenced
in
the
VC,
before
accepting
a
credential
as
valid.
Motivations
Verifiers
need
to
be
able
to
apply
their
own
policies
and
rules
to
the
information
they
rely
on
to
run
their
"business"
(which
we
mean
broadly,
to
encompass
all
activity
focused
towards
a
goal).
Given
this
need,
any
given
VC
might
be
verified
but
not
usable
in
a
particular
situation.
For
example,
a
self-issued
driver's
license
would
likely
not
be
acceptable
for
a
car
rental
by
most
car
rental
agencies,
even
though
the
verification
succeeds.
Even
so,
in
other
cases,
such
as
at
a
go-cart
racing
facility,
it
may
be
entirely
appropriate
to
accept
the
name
and
image
from
a
self-issued
license
for
the
purpose
of
leaderboards,
announcements,
and
correspondence.
These
business
rules
are
entirely
the
province
of
the
verifier.
Only
after
satisfying
their
rules
should
a
verifier
rely
upon
a
claim
as
an
accepted
fact
for
specific
use.
Needs
F.2
,
C.1
,
E.2
,
R.1
,
F.5
,
H.2
,
C.6
4.5
Store
Claim
Requirement
It
MUST
be
possible
for
the
holder
of
a
claim
to
store
that
claim
in
one
or
more
credential
repositories
.
Motivation
A
claim
is
under
the
control
of
its
holder
.
That
holder
will
choose
where
their
claims
are
stored
based
upon
a
variety
of
factors
(e.g.,
employer
requirements,
convenience,
service
levels,
provider
cost,
business
intelligence).
The
holder
needs
to
be
able
to
easily
choose
among
various
credential
repositories
,
and
also
to
be
able
to
migrate
their
claims
to
another
without
requesting
new
claims
from
the
claim
issuer
.
Needs
F.4
,
E.3
,
C.4
4.6
Retrieve
Claim
Requirement
It
MUST
be
possible
for
a
holder
to
select
if
and
which
appropriate
credential
should
be
sent
to
a
verifier
.
It
MUST
be
possible
for
the
issuer
of
a
claim
to
revoke
it,
after
which
it
will
no
longer
satisfy
verification
procedures.
Motivation
An
entity
(
issuer
)
discovers
that
a
claim
they
have
issued
and
are
endorsing
for
an
end
user
(
subject
),
is
no
longer
valid
and
wishes
to
revoke
the
issued
claim.
Needs
F.3
,
C.2
,
C.3
5.
Focal
Use
Cases
Focal
Use
Cases
are
meant
to
provide
examples
where
a
blend
of
features
from
verifiable
credentials
standard
may
be
used
together
to
solve
complex
or
challenging
marketplace
needs.
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5.1
Citizenship
by
Parentage
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/uploads/YqAdm5/focal/4_gs1_identification.html
5.1.1
Background
Sam
wants
to
claim
US
citizenship
because
his
mother
is
American.
Sam
has
a
digital
birth
certificate
from
Kenya,
where
he
was
born
while
his
Mother
was
in
the
Peace
corps.
He
also
has
a
digital
version
of
his
mother's
US
passport.
Because
his
mother’s
name
changed
between
his
birth
and
the
issuance
of
the
passport,
Sam
also
has
a
marriage
license
with
her
maiden
and
married
names.
Sam
is
applying
for
a
new
passport
from
the
US
Secretary
of
State.
5.1.2
Distinction
This
use
case
is
challenging
because
the
mother’s
name
changed,
by
marriage,
between
the
issuance
of
the
birth
certificate
and
passport.
5.1.3
Scenario
Sam’s
mother
emailed
him
the
certificate,
license,
and
passport
as
independent
Verifiable
Credentials
.
He
then
creates
a
verifiable
presentation
which
includes
those
credentials,
a
statement
of
their
relationship
to
each
other
and
his
relationship
to
his
mother.
He
then
visits
the
US
Secretary
of
State
website,
creates
an
account,
starts
the
application
for
a
passport,
and
uploads
his
new
verifiable
presentation
as
supporting
evidence.
After
processing
the
application,
Sam
is
issued
both
a
traditional
passport
and
a
new
digital
passport.
5.1.4
Verifiable
Credentials
Birth
Certificate
Establishes
relationship
to
mother
with
maiden
name
Marriage
License
Establishes
mother's
name
change
Mother’s
Passport
Establishes
mother's
US
citizenship
Sam’s
Passport
Establishes
Sam
is
the
child
in
the
birth
certificate
The
mother
in
the
birth
certificate,
the
person
in
the
passport,
the
spouse
in
the
marriage
license
are
all
the
same
person.
5.1.6
Trust
Hierarchy
Sam
is
legally
liable
for
his
claim
to
the
rights
of
citizenship.
The
state
department
is
on
the
hook
for
verifying
the
underlying
credentials
and
Sam’s
claims
,
including
correlating
against
any
additional
data
they
might
already
have.
5.1.7
Threat
model
Threat:
Terrorist
/
Identity
fraud.
A
bad
actor
could
be
impersonating
Sam
to
attain
a
passport.
Of
course,
if
a
bad
actor
were
to
be
able
to
collect
the
required
verifiable
credentials
—mother’s
passport,
birth
certificate,
and
marriage
license,
that
actor
has
already
significantly
compromised
the
system.
Response:
Identity
assurance
based
on
the
contents
of
the
claims
,
potentially
with
enhanced
data
embedded
in
the
claims
,
i.e.,
data
not
currently
in
passports,
birth
certificates,
or
marriage
license.
For
example,
a
biometric
template
could
be
embedded
in
the
birth
certificate
claim
and
that
template
could
be
used
for
interactive
identity
assurance
at
the
time
of
submitting
the
presentation
.
Threat:
Exposure
of
private
information.
By
storing
potentially
compromising
information
in
credentials
and
sending
them
over
the
network,
we
are
increasing
the
attack
surface
for
the
subjects
of
those
credentials.
Response:
Encrypt
the
claims
(once
by
issuer,
every
verifier
gets
the
same
encrypted
blob)
Pat
earned
multiple
diving
credentials
while
living
and
working
in
Fiji
and
Australia.
Later,
Pat
is
hired
by
NOAA
as
a
Dive
Instructor,
which
requires
that
they
maintain
certification
as
an
instructor
with
additional
specialist
diver
certifications
in
dry
suit,
night
diving,
and
search
and
recovery.
The
dive
instructor
certification
is
public
record,
but
the
additional
specialist
certifications
are
private
because
they
are
for
personal
diving,
not
acting
as
an
instructor.
Part
of
Pat's
job
is
logging
the
certifications
of
fellow
divers
during
NOAA
sanctioned
dives.
5.2.2
Distinction
This
use
case
is
difficult
because:
Certification
in
Fiji
and
Australia.
NOAA
relies
on
an
international
certification
agency,
PADI,
with
relevance
in
multiple
jurisdictions.
Each
of
these
credentials
is
issued
by
different
schools
in
the
name
of
PADI.
Each
credential
has
an
independent
expiration
cycle.
Pat
grants
NOAA
permission
(the
capability)
to
validate
future
credential
status
changes.
When
Pat
applied
for
his
job
at
NOAA,
he
provided
verifiable
credentials
issued
by
different
dive
schools
licensed
by
PADI
to
do
so.
NOAA
verifies
cryptographically
that
the
certifications
were
issued
by
PADI-approved
dive
schools
and
that
the
credentials
were
still
in
good
standing
by
checking
both
the
certifications'
*and*
the
dive
schools'
revocation
services.
Upon
accepting
the
job,
Pat
issues
NOAA
a
revocable
token
that
allows
NOAA
to
check
the
current
status
of
all
of
his
certifications
—
not
just
the
status
of
a
single
verifiable
credential
.
After
any
specific
certification
expires
—
and
Pat
renews
it
—
NOAA's
next
check
of
Pat's
certifications
returns
the
status
of
the
renewed
certification,
not
just
the
status
of
the
(now
expired)
verifiable
credential
.
When
Pat
takes
a
group
of
divers
on
NOAA
sanctioned
dives,
he
records
the
verifiable
credentials
for
each
diver
(which
demonstrate
their
diving
certifications),
creates
a
verifiable
credential
including
those
credentials
;
he
signs
and
archives
it
on
his
laptop.
When
Pat
retires
from
NOAA,
he
revokes
that
token
and
NOAA
staff
is
no
longer
able
to
monitor
his
non-public
certification
status.
PADI
is
liable
for
correctly
certifying
dive
schools.
Dive
schools
are
liable
for
correctly
certifying
Pat's
knowledge
and
skills.
Pat
is
liable
for
representing
the
facts
in
their
application
and
maintaining
the
revocable
capability.
NOAA
is
liable
for
verifying
the
credentials
and
Pat's
assertions
claiming
them,
and
for
assuring
Pat's
continued
good
standing
for
the
required
credentials
.
Pat
is
liable
for
making
sure
all
divers,
on
each
trip,
have
valid
credentials
and
are
properly
logged.
Threat:
Pat
could
send
a
proxy
to
earn
their
certificate
.
Response:
School
should
use
multi-factor
identity
assurance
during
registration
and
onsite
when
testing.
Response:
Dive
school
retains
video
surveillance
of
event
for
future
audits
Response:
Dive
boat
or
test
center
takes
photos
of
participants
and
logs
them
for
later
audit
Threat:
Pat
or
another
dive
master
could
lie
about
a
diver
being
on
the
boat
.
Response:
NOAA
requires
divers
listed
to
submit
endorsement
that
they
were
there
(they
endorse
the
dive
log);
divers
mutually
sign
each
other's
log
entries
Response:
Boat
owner
signs
dive
log
Response:
Pre-register
excursion
and
expected
diver
list
Response:
Ongoing
signed
provenance
data
about
Pat's
job
assignments
(location,
dates,
correspondence,
etc)
by/with
NOAA
Manifest
"souls
on
board"
before/after
including
crew
Response:
Independent
ID
proofing
of
offline
credentials
(signed
picture
and/or
photo
ID)
Response:
Isolate
issuer
agent
system
to
an
air-gapped
environment
Threat:
Pat
is
phished,
and
Pat
gives
capability
to
the
wrong
person/entity
.
Response:
Use
better
identity
assurance
for
the
verifier,
i.e.,
don't
give
capability
to
strangers.
Response:
Use
Object
Capabilities
based
on
strong
authentication
and
well-known
public
keys.
Threat:
Issuer
spoofs
Pat,
and
Pat
receives
VC
from
non-PADI-certified
instructor
.
Response:
Pat
runs
PADI's
wallet
software
to
make
sure
any
certificates
they
receive
are
authentic.
Response:
Pat
checks
the
VC
with
a
PADI-provided
tool
before
accepting
it
Response:
Pat
checks
the
VC
with
a
standard
tool,
to
see
that
(1)
There
really
is
a
PADI
authentication
and
(2)
PADI
authentication
is
actually
from
PADI
Threat:
Pat
presents
a
fake
credential
as
a
PADI
certification
.
Response:
NOAA
verifies
the
signature
on
the
certification
credential
AND
on
the
PADI
authentication
credential.
Threat:
Pat's
laptop
on
the
boat
could
be
compromised
.
Response:
Use
air-gapping
techniques,
such
as
QR
codes,
to
limit
impact
of
compromise
5.3
International
Travel
with
Minor
and
Upgrade
5.3.1
Background
Malathi
is
traveling
internationally
with
her
8-month-old
son,
Anand.
His
father,
Rajesh,
is
staying
home.
Malathi
has
enough
frequent
flyer
miles
to
upgrade
the
ticket
to
first
class.
5.3.2
Distinction
This
use
case
is
difficult
because:
Current
US
passports
do
not
establish
explicit
relationship
between
parent
and
child.
When
one
parent
travels
with
a
minor,
the
other
parent
is
required
to
grant
permission
for
the
trip,
thus
implying
guardianship
or
responsibility.
The
DID
or
other
Digital
Identity
system
replaces
the
role
of
the
notary
in
the
paper/physical
world
Credentials
must
be
coordinated
between
two
verifiers
(agent
and
airline)
for
two
individuals,
and
a
digital
coupon
is
used.
The
relationship
of
the
minor
to
the
non-traveling
parent
must
be
established,
in
order
for
the
permission
to
be
considered.
Malathi
obtains
permission
from
Rajesh
stating
she
is
allowed
to
take
the
baby
out
of
the
country.
Prior
to
booking
the
trips,
Malathi
visits
HappyAir.com
to
request
an
upgrade
to
first
class.
HappyAir
issues
a
verifiable
credential
redeemable
for
a
first
class
upgrade
on
an
international
flight.
She
books
the
plane
tickets
through
her
travel
agent
who
adds
the
lap
child
to
the
ticket.
HappyAir
verifies
that
Malathi
has
a
signed
statement
from
Anand’s
other
parent
stating
that
she
may
exit
the
country
with
him.
5.3.4
Verifiable
Credentials
Malathi's
passport
Establishes
identity
of
the
traveling
parent
Anand's
passport
Establishes
identity
of
the
minor
Anand's
Birth
Certificate
Establishes
relationship
to
parents
and
provides
link
from
Rajesh
to
Anand
that
qualifies
the
permission
to
travel
Permission
to
travel
from
Rajesh
Grants
permission
from
non-traveling
parent
for
minor
to
travel.
Identity
matches
identity
of
the
parent
in
the
birth
certificate,
establishing
relevance.
Submitted
to
HappyAir,
includes
Malathi
and
Anand's
passport,
assertion
of
permission,
birth
certificate
and
Frequent
Flyer
coupon.
5.3.6
Trust
Hierarchy
Malathi
is
liable
for
her
claim
of
parentage
as
well
as
securing
right
to
admission
for
herself
and
her
son
at
their
destination
(visa
may
be
required).
Malathi
and
Rajesh
are
both
liable
for
attestation
of
permission
to
fly
with
Anand
without
the
other
parent.
Malathi
is
liable
for
the
cost
of
her
ticket
and
her
son’s
ticket.
The
agency
is
liable
for
issuing
valid
tickets
and
for
verifying
the
credentials
provided
by
the
travelers.
The
airline
is
liable
for
issuing
tickets
and,
ultimately,
fulfilling
the
terms
of
travel
The
airline
is
liable
for
accepting
the
upgrade
coupons
at
ticketing.
The
airline
is
liable
for
verifying
the
credentials
in
the
birth
certificate
match
the
credentials
in
the
permission
letter.
The
check-in
agent,
TSA
agent,
and
passport
control
at
the
destination
are
liable
for
identity
assurance
at
various
points
of
travel,
using
information
contained
in
the
verifiable
credentials
.
5.3.7
Threat
model
Threat:
Stolen
Key.
Malathi
steals
Rajesh’s
key
in
order
to
fake
travel
permission.
(Kidnapping
her
own
kids
and
fleeing
Rajesh.)
Response:
Rajesh
could
store
his
key
with
a
trusted
third
party,
such
as
an
attorney.
Response:
Rajesh
could
use
a
hardware
wallet
with
pin
or
biometric.
Response:
Rajesh
could
use
a
passphrase
on
his
key
Threat:
Stolen
Key
2
Ticket
purchaser
has
Malathi’s
credentials
,
impersonating
her
to
purchase
a
ticket.
This
could
enable
a
third-party
kidnapping.
Response:
Travel
permission
can
be
restricted
to
specific
date
and
or
trip
minimizing
abuse
potential.
Response:
Embed
identifying
characteristics
or
biometric
into
the
credentials
so
that
verifiers
can
independently
verify
the
subject
in
front
of
them
is
the
subject
in
the
credential
.
Response:
Malathi
could
use
a
hardware
wallet
with
pin
or
biometric.
Response:
Malathi
could
use
a
passphrase
on
her
key
Threat:
Exposure
of
private
information.
By
storing
potentially
compromising
information
in
credentials
and
sending
them
over
the
network,
we
are
increasing
the
attack
surface
for
the
subjects
of
those
credentials.
GS1
is
the
global
supply
chain
standards
development
organization
behind
the
retail
barcode.
The
content
of
the
barcode,
the
Global
Trade
Item
Number
(GTIN),
is
a
13-digit
string
composed
of
a
GS1
Company
Prefix
(a
unique
string
of
4-12
digits),
a
trade
item
reference
(a
numeric
string
unique
within
the
GS1
Company
Prefix
to
bring
the
length
up
to
12
digits),
and
a
check
digit
(a
mathematical
calculation
to
detect
keying
errors).
The
GS1
Company
Prefix
is
licensed
to
a
user
company
by
a
local
GS1
Member
Organization.
The
license
gives
the
user
company
the
right
to
issue
GS1
identification
keys
within
the
range
of
the
GS1
Company
Prefix
and
to
issue
Verifiable
Credentials
referring
to
the
license
Verifiable
Credential.
The
license
Verifiable
Credential
may
be
revoked
if
the
user
company
fails
to
abide
by
the
terms
and
conditions
or
may
be
transferred
to
another
user
company
as
part
of
a
merger
and
acquisition.
If
the
license
is
revoked,
no
new
Verifiable
Credentials
derived
from
it
may
be
issued.
If
the
license
is
transferred,
existing
derived
Verifiable
Credentials
remain
valid,
and
the
new
user
company
may
issue
new
Verifiable
Credentials,
including
some
that
refer
to
Verifiable
Credentials
issued
by
the
previous
user
company.
Note
The
core
GS1
standard
is
the
identification
of
objects
in
the
supply
chain,
typically
trade
items,
but
also
locations,
shipping
containers,
and
much
more.
Every
object
is
identified
using
a
GS1
identification
key,
sometimes
alongside
a
secondary
key
for
higher
granularity
(e.g.,
a
serial
number
alongside
a
GTIN
to
identify
a
specific
instance
of
a
trade
item).
Much
of
the
text
in
this
use
case
refers
to
keys
and
key
credentials.
These
are
the
GS1
identification
keys,
not
cryptographic
keys.
5.4.2
Distinction
This
differs
from
other
focal
use
cases
in
that
the
rights
granted
by
a
Verifiable
Credential
can
be
transferred
to
another
subject,
without
invalidating
other
Verifiable
Credentials
created
by
the
original
subject.
5.4.3
Scenario
Healthy
Tots,
a
baby
food
manufacturer,
wishes
to
list
its
products
on
the
Sell
Anything
&
Everything
(SA&E)
marketplace.
As
a
global
marketplace,
SA&E
requires
unique
identification
for
products
listed
on
its
site,
and
has
chosen
the
GTIN
as
the
preferred
identification
key.
To
ensure
uniqueness,
SA&E
requires
that
companies
listing
products
prove
that
they
have
the
right
to
issue
the
GTINs
they
are
using.
5.4.4
Verifiable
Credentials
GS1
Prefix
license
Issued
by
GS1
Global
Office
to
GS1
Utopia
(a
GS1
Member
Organization
operating
in
the
region
of
Utopia).
Grants
GS1
Utopia
the
right
to
issue
GS1
Company
Prefix
licenses
within
the
range
of
the
GS1
Prefix
in
the
license.
GS1
Company
Prefix
license
Issued
by
GS1
Utopia
to
Healthy
Tots.
Grants
Healthy
Tots
the
right
to
issue
GS1
identification
keys
within
the
range
of
the
GS1
Company
Prefix
in
the
license.
Key
(GTIN)
Issued
by
Healthy
Tots
to
declare
the
existence
of
a
GS1
identification
key,
typically
a
GTIN,
within
the
range
of
the
GS1
Company
Prefix.
GS1
Global
Office,
the
trusted
root
of
the
GS1
identification
system
GS1
Utopia,
a
GS1
Member
Organization,
a
country-based
member
of
the
GS1
federation,
also
a
GS1
Prefix
licensee
Healthy
Tots,
a
baby
food
manufacturer,
also
a
GS1
Company
Prefix
licensee
Sell
Anything
&
Everything
(SA&E),
a
global
marketplace
A
trade
item
manufactured
and
sold
by
Healthy
Tots,
represented
as
a
GS1
Digital
Link
URI
Benevolent
Conglomerate,
a
company
that
acquires
Healthy
Tots
and,
optionally,
its
GS1
licenses
5.4.5.1
Issuer
For
the
GS1
Prefix
license
Verifiable
Credential,
the
issuer
is
GS1
Global
Office.
For
the
GS1
Company
Prefix
license
Verifiable
Credential,
the
issuer
is
GS1
Utopia,
which
is
the
subject
of
the
corresponding
GS1
Prefix
license
Verifiable
Credential.
For
the
trade
item
Verifiable
Credential,
the
issuer
is
Healthy
Tots,
which
is
the
subject
of
the
corresponding
GS1
Company
Prefix
license
Verifiable
Credential.
5.4.5.2
Subject
For
the
GS1
Prefix
license
Verifiable
Credential,
the
subject
is
GS1
Utopia.
For
the
GS1
Company
Prefix
license
Verifiable
Credential,
the
subject
is
Healthy
Tots.
For
the
trade
item
Verifiable
Credential,
the
subject
is
the
GTIN
represented
as
a
GS1
Digital
Link
URI.
5.4.5.3
Holder
For
the
GS1
Prefix
license
Verifiable
Credential,
the
holder
is
GS1
Utopia.
For
the
GS1
Company
Prefix
license
Verifiable
Credential,
the
holder
is
Healthy
Tots.
For
the
trade
item
Verifiable
Credential,
the
holder
is
Healthy
Tots.
5.4.5.4
Verifier
Sell
Anything
&
Everything,
a
trading
partner
of
Healthy
Tots
that
needs
to
validate
the
identification
of
an
object
(typically
a
trade
item)
and
the
data
associated
with
it.
5.4.6
Validation
Requirements
The
validity
of
a
credential
often
depends
on
the
validity
of
a
prior
credential
and
on
comparison
of
data
between
the
credential
of
interest
and
its
prior
credential.
The
validation
process
is
recursive,
ending
only
when
there
is
no
further
prior
credential
and
the
first
credential
(the
one
with
no
prior
credential)
is
issued
by
GS1
Global
Office.
Within
the
GS1
vocabularly,
a
credential
that
depends
on
a
prior
credential
is
said
to
extend
the
prior
credential.
Accordingly,
every
such
credential
has
an
"extendsCredential"
property
that
references
the
ID
of
the
prior
credential;
the
absence
of
this
property
indicates
the
first
credential.
A
GS1
Prefix
license
Verifiable
Credential
is
valid
if
it
is
issued
by
GS1
Global
Office.
A
GS1
Company
Prefix
license
Verifiable
Credential
is
valid
if:
the
issuer
is
the
same
as
the
subject
of
the
"extendsCredential";
the
GS1
Company
Prefix
in
"licenseValue"
("9521234"
in
the
examples)
starts
with
the
same
digits
as
the
GS1
Prefix
in
"licenseValue"
of
the
"extendsCredential"
("952"
in
the
examples);
and
the
credential
was
issued
after
the
"extendsCredential"
was
issued
and,
if
applicable,
before
the
"extendsCredential"
was
revoked
or
transferred.
A
key
(GTIN)
Verifiable
Credential
is
valid
if:
the
issuer
is
the
same
as
the
subject
of
the
"extendsCredential";
the
key
(GTIN)
in
"credentialSubject.id"
("09521234555551"
in
the
examples)
is
properly
based
on
the
GS1
Company
Prefix
in
"licenseValue"
of
the
"extendsCredential";
the
credential
was
issued
after
the
"extendsCredential"
was
issued
and,
if
applicable,
before
the
"extendsCredential"
was
revoked
or
transferred;
and
the
GS1
Company
Prefix
license
Verifiable
Credential
is
valid.
5.4.7
Verifiable
Presentation
Healthy
Tots
presents
the
credential
for
the
key
(GTIN)
that
it
has
issued
to
identify
its
product
as
well
as
the
GS1
Company
Prefix
license
credential
to
prove
that
it
has
the
right
to
issue
the
key
to
SA&E.
To
complete
the
validation,
SA&E
requires
the
GS1
Prefix
license
credential
issued
to
GS1
Utopia,
which
is
publicly
accessible
and
discoverable
via
the
GS1
Company
Prefix
license
credential.
5.4.8
Trust
Hierarchy
GS1
Global
Office
is
responsible
for
management
of
the
GS1
identification
system
as
a
whole.
It
is
liable
for
ensuring
that
the
GS1
Prefix
licenses
that
it
issues
are
unique.
GS1
Utopia
is
responsible
for
management
of
the
GS1
identification
system
within
the
range(s)
of
the
GS1
Prefix(es)
issued
to
it.
It
is
liable
for
ensuring
that
the
GS1
Company
Prefix
licenses
that
it
issues
are
unique.
Healthy
Tots
is
responsible
for
management
of
the
GS1
identification
system
within
the
range(s)
of
the
GS1
Company
Prefix(es)
issued
to
it.
It
is
liable
for
ensuring
that
the
GS1
identification
keys
that
it
issues
are
unique.
SA&E
is
responsible
for
ensuring
that
no
two
products
listed
on
its
website
carry
the
same
GTIN.
5.4.9
Variation
-
License
Transfer
GS1
license
Verifiable
Credentials
are
issued
with
a
validFrom
property
but
not
a
validUntil
property.
Licenses
are
renewable
as
long
as
the
licensee
abides
by
the
terms
and
conditions
of
the
GS1
Member
Organization
that
issued
the
license,
including
regular
license
payment
if
required.
Accordingly,
the
only
way
for
a
trading
partner
to
know
that
a
license
is
no
longer
valid
is
to
check
its
status
for
revocation.
5.4.9.1
Revocation
Once
a
license
credential
is
revoked,
any
extension
credentials
(those
that
extend
the
revoked
credential
or
that
extend
other
extension
credentials)
created
after
the
revocation
are
invalid.
For
example,
a
GTIN
key
credential
created
after
the
revocation
of
the
underlying
GS1
Company
Prefix
license
credential
is
invalid
because
the
company
no
longer
has
the
right
to
issue
GTINs,
or
any
other
key,
within
the
scope
of
the
GS1
Company
Prefix.
Other
dependent
credentials
that
are
created
after
revocation
may
be
valid,
such
as
a
product
recall
notice
linked
to
a
GTIN
key
credential
created
before
the
revocation.
Extension
credentials
created
prior
to
the
revocation
of
an
extended
credential
may
be
considered
valid
for
certain
use
cases.
The
key
credential
used
to
identify
a
trade
item
with
a
GTIN,
for
example,
will
remain
valid
in
perpetuity,
long
after
trade
items
identified
by
the
GTIN
are
no
longer
in
the
supply
chain.
Some
of
the
data
credentials
associated
with
the
GTIN,
such
as
those
that
describe
the
product
or
that
provide
information
such
as
recycling
instructions,
may
also
be
valid
well
beyond
the
revocation
of
the
GS1
Company
Prefix
license
credential.
5.4.9.2
Suspension
Suspension
of
a
license
is
an
intermediate
step
for
some
GS1
Member
Organizations,
to
give
the
licensee
the
opportunity
to
come
back
into
compliance
with
the
terms
and
conditions
of
their
agreement.
In
general,
a
suspended
credential
should
be
treated
as
revoked,
with
the
caveat
that
the
suspension
status
could
be
removed
entirely
or
replaced
with
the
revocation
status.
Verifiers
should
therefore
check
the
credential
status
periodically
until
one
or
the
other
occurs.
5.4.9.3
Replacement
Replacement
is
similar
to
revocation
in
that
it
invalidates
the
credential,
but
it
indicates
that
there
is
another,
equivalent
credential
available.
The
most
common
use
case
for
this
is
in
acquisitions
and
mergers,
as
defined
in
the
GS1
General
Specifications:
During
an
acquisition
or
merger,
a
company
may
assume
responsibility
for
the
acquired
company's
GS1
Company
Prefix
and/or
individual
GS1
identification
key
licences.
In
the
situations
where
the
licences
transfer,
the
acquiring
company
can:
Use
the
acquired
company's
GS1
Company
Prefix(es)
and
GS1
identification
key(s
Issue
GS1
identification
keys
using
the
newly
acquired
GS1
Company
Prefix(es)
For
example,
products
that
the
acquired
company
identified
using
its
GS1
Company
Prefix
or
individual
GS1
identification
key
licences
can
still
be
produced
using
the
same
GTINs
after
the
merger.
Additionally,
parties,
locations,
assets,
and
other
objects
identified
with
GS1
identification
keys
can
continue
to
use
those
keys
after
the
merger.
If
a
partial
purchase
occurs,
where
only
a
segment
of
a
larger
entity
is
acquired,
the
involved
companies
must
determine
whether
GS1
identification
licences
are
transferred
based
on
their
specific
business
requirements.
In
such
a
situation,
the
acquiring
company
takes
over
the
licenses
of
the
acquired
company
and
should
be
issued
the
appropriate
credentials.
Those
originally
issued
to
the
acquired
company
are
no
longer
valid,
but
simple
revocation
could
be
highly
disruptive
as
there
may
be
thousands
of
extension
credentials
that
could
be
invalidated
by
the
business
rules
that
apply
to
revocation.
Instead,
the
replacement
status
indicates
that
the
licence
credential
has
been
replaced.
As
with
revocation,
any
new
extension
credentials
that
directly
reference
the
replaced
credential
are
invalid,
but
pre-existing
extension
credentials
should
be
validated
against
the
replacement
credential
using
the
normal
business
rules.
Suppose
that
Healthy
Tots
is
acquired
by
Benevolent
Conglomerate.
Benevolent
Conglomerate
may
decide
on
a
hands-off
approach
and
leave
Healthy
Tots
to
continue
its
operations
much
as
before,
with
no
impact
on
the
way
that
the
GS1
identification
keys
are
managed.
It's
possible,
though,
that
Benevolent
Conglomerate
will
decide
to
discontinue
Healthy
Tots
as
a
separate
entity
and
instead
absorb
its
products
into
a
central
catalogue.
The
GS1
Company
Prefix
license,
originally
issued
to
Healthy
Tots,
will
be
transferred
by
GS1
Utopia
to
Benevolent
Conglomerate.
In
this
case,
a
status
check
of
the
original
GS1
Company
Prefix
license
Verifiable
Credential
must
indicate
a
status
of
"replaced"
and,
potentially,
include
the
ID
of
the
replacement.
Regardless
of
whether
the
status
indicates
the
ID
of
the
replacement
credential,
the
replacement
must
reference
the
credential
it
replaced.
The
maintain
continuity
of
supply
chain
management,
the
following
must
be
supported:
The
original
key
credentials
issued
by
Healthy
Tots
remain
valid,
as:
they
were
issued
prior
to
the
replacement;
the
replacement
references
the
original
license
credential;
using
a
combination
of
the
original
and
replacement
credentials,
the
key
credentials
can
be
validated
according
to
the
business
rules;
and
the
replacement
GS1
Company
Prefix
license
Verifiable
Credential
has
not
been
revoked.
Benevolent
Conglomerate
can
issue
new
key
Verifiable
Credentials
based
on
the
GS1
Company
Prefix
license
Verifiable
Credential.
Benevolent
Conglomerate
can
issue
additional
Verifiable
Credentials
based
on
the
key
Verifiable
Credentials
issued
by
Healthy
Tots,
as
the
transfer
(replacement)
of
the
GS1
Company
Prefix
license
Verifiable
Credential
provides
an
authenticated
chain
of
responsibility.
6.
Extant
Use
Cases
Extant
Use
Cases
are
illustrative
of
market
adoption,
i.e.,
examples
of
the
use
of
verifiable
credentials
in
real-world
applications.
7.
User
Sequences
The
transaction
examples
in
this
section
show
basic
ways
in
which
verifiable
credentials
might
be
used.
They
are
not
meant
to
be
architecturally
constraining.
Instead,
they
are
meant
to
help
illustrate
the
basic
way
it
could
be
done
in
a
typical
commerce
situation.
Again
—
please
remember
that
it
is
just
an
example,
and
should
not
be
thought
of
as
the
canonical
way
such
a
claims
environment
must
be
implemented.
7.1
How
a
Verifiable
Credential
Might
Be
Created
In
this
first
example,
a
user
will
request
a
verifiable
credential—a
confirmation
of
their
identity.
Consider
this
illustration:
Jane
selects
one
of
these,
and
authorizes
that
it
be
shared
with
the
merchant.
The
credential
repository
returns
the
selected
credential
as
a
response
to
the
user
agent-supported
API
call,
which
in
turn
delivers
it
to
the
merchant.
The
merchant's
server
verifies
that
the
claim
is
valid
and
satisfies
the
requirement.
The
merchant
redirects
the
user
agent
to
the
web
site
with
appropriate
authorization.
A.
Terminology
This
section
is
non-normative.
Error
Cannot
GET
/uploads/YqAdm5/terms.html
The
following
terms
are
used
to
describe
concepts
in
this
specification.
A
set
of
one
or
more
claims
made
by
an
issuer
.
A
verifiable
credential
is
a
tamper-evident
credential
that
has
authorship
that
can
be
cryptographically
verified.
Verifiable
credentials
can
be
used
to
build
verifiable
presentations
,
which
can
also
be
cryptographically
verified.
The
claims
in
a
credential
can
be
about
different
subjects
.
data
minimization
The
act
of
limiting
the
amount
of
shared
data
strictly
to
the
minimum
necessary
to
successfully
accomplish
a
task
or
goal.
decentralized
identifier
A
portable
URL-based
identifier,
also
known
as
a
DID
,
associated
with
an
entity
.
These
identifiers
are
most
often
used
in
a
verifiable
credential
and
are
associated
with
subjects
such
that
a
verifiable
credential
itself
can
be
easily
ported
from
one
repository
to
another
without
the
need
to
reissue
the
credential
.
An
example
of
a
DID
is
did:example:123456abcdef
.
A
verifiable,
boolean
assertion
about
the
value
of
another
attribute
in
a
verifiable
credential
.
These
are
useful
in
zero-knowledge-proof-style
verifiable
presentations
because
they
can
limit
information
disclosure.
For
example,
if
a
verifiable
credential
contains
an
attribute
for
expressing
a
specific
height
in
centimeters,
a
derived
predicate
might
reference
the
height
attribute
in
the
verifiable
credential
demonstrating
that
the
issuer
attests
to
a
height
value
meeting
the
minimum
height
requirement,
without
actually
disclosing
the
specific
height
value.
For
example,
the
subject
is
taller
than
150
centimeters.
digital
signature
A
mathematical
scheme
for
demonstrating
the
authenticity
of
a
digital
message.
entity
A
thing
with
distinct
and
independent
existence,
such
as
a
person,
organization,
or
device
that
performs
one
or
more
roles
in
the
ecosystem.
graph
A
network
of
information
composed
of
subjects
and
their
relationship
to
other
subjects
or
data.
The
means
for
keeping
track
of
entities
across
contexts.
Digital
identities
enable
tracking
and
customization
of
entity
interactions
across
digital
contexts,
typically
using
identifiers
and
attributes.
Unintended
distribution
or
use
of
identity
information
can
compromise
privacy.
Collection
and
use
of
such
information
should
follow
the
principle
of
data
minimization
.
identity
provider
An
identity
provider,
sometimes
abbreviated
as
IdP
,
is
a
system
for
creating,
maintaining,
and
managing
identity
information
for
holders
,
while
providing
authentication
services
to
relying
party
applications
within
a
federation
or
distributed
network.
In
this
case
the
holder
is
always
the
subject
.
Even
if
the
verifiable
credentials
are
bearer
credentials
,
it
is
assumed
the
verifiable
credentials
remain
with
the
subject
,
and
if
they
are
not,
they
were
stolen
by
an
attacker.
This
specification
does
not
use
this
term
unless
comparing
or
mapping
the
concepts
in
this
document
to
other
specifications.
This
specification
decouples
the
identity
provider
concept
into
two
distinct
concepts:
the
issuer
and
the
holder
.
Data
derived
from
one
or
more
verifiable
credentials
,
issued
by
one
or
more
issuers
,
that
is
shared
with
a
specific
verifier
.
A
verifiable
presentation
is
a
tamper-evident
presentation
encoded
in
such
a
way
that
authorship
of
the
data
can
be
trusted
after
a
process
of
cryptographic
verification.
Certain
types
of
verifiable
presentations
might
contain
data
that
is
synthesized
from,
but
do
not
contain,
the
original
verifiable
credentials
(for
example,
zero-knowledge
proofs).
A
role
a
system
might
perform
by
mediating
the
creation
and
verification
of
identifiers,
keys,
and
other
relevant
data,
such
as
verifiable
credential
schemas,
revocation
registries,
issuer
public
keys,
and
so
on,
which
might
be
required
to
use
verifiable
credentials
.
Some
configurations
might
require
correlatable
identifiers
for
subjects
.
Some
registries,
such
as
ones
for
UUIDs
and
public
keys,
might
just
act
as
namespaces
for
identifiers.
verification
The
evaluation
of
whether
a
verifiable
credential
or
verifiable
presentation
is
an
authentic
and
timely
statement
of
the
issuer
or
presenter,
respectively.
This
includes
checking
that:
the
credential
(or
presentation)
conforms
to
the
specification;
the
proof
method
is
satisfied;
and,
if
present,
the
status
is
successfully
checked.
verifier
The
entity
verifying
a
claim
about
a
given
subject.
URI
A
Uniform
Resource
Identifier,
as
defined
by
[
RFC3986
].
B.
Example
Verifiable
Credentials
Error
Cannot
GET
/uploads/YqAdm5/focal/3_international_travel_with_minor_and_upgrade_examples.html
B.1
Focal
Use
Case:
International
Travel
with
Minor
and
Upgrade
The
key
artefact
is
the
last
one;
it
declares
the
existence
of
a
GTIN,
around
which
other
Verifiable
Credentials
may
be
issued
to
declare
data
about
the
trade
item
(brand,
size
and
unit
of
measure,
ingredients,
dimensions
and
weights,
etc.).
Validation
of
the
artefact
requires
validating
all
the
credentials
that
come
before
it,
identified
in
each
case
by
"extendsCredential".
Example
6
:
GS1
Prefix
952
Licensed
by
GS1
Global
Office
to
GS1
Utopia
The
editors
are
thankful
to
the
contributions
from
the
Web
Payments
Workshop,
the
Web
Payments
Community
Group,
the
Web
Payments
Interest
Group,
the
Credentials
Community
Group,
the
Verifiable
Claims
Task
Force,
and
the
Verifiable
Claims
Working
Group.