From afe49ce15eff039b4fa15271c549f7c0bc5dfbca Mon Sep 17 00:00:00 2001
From: Manu Sporny Use Cases and Requirements
-Verifiable credential and verifiable presentation MUST be protected using a digital proof -mechanism such as a digital signature. Having and -verifying proofs, which may be dependent on the syntax of the proof -(for example, using the JSON Web Signature of a JSON Web Token for proofing a -key holder), are an essential part of processing verifiable credentials and verifiable presentations. -At the time of publication, Working Group members had implemented -such protection using at least three proof mechanisms: +Verifiable credential and verifiable presentation MUST be +protected using a digital proof mechanism such as a digital signature. Having +and verifying proofs, which may be dependent on the syntax of the proof (for +example, using the JSON Web Signature of a JSON Web Token for proofing a key +holder), are an essential part of processing verifiable credentials and +verifiable presentations. At the time of publication, Working Group +members had implemented such protection using at least three proof mechanisms:
In the example above, the issuer is asserting that as a European
Blockchain Services Infrastructure (EBSI) accredited issuer, it complies with the EBSI
-policies as an accredited issuer and is registered in the EBSI register of trusted issuers.
+policies as an accredited issuer and is registered in the EBSI register of trusted issuers.
The termsOfUse
id can be resolved by the verifier to check
whether the issuer has been issued an accreditation VC (in JWT format)
by a trusted issuer higher in the EBSI trust chain [?EBSI].
@@ -3999,8 +3993,8 @@
verifiableCredential
and proof
properties
-are defined as JSON-LD 1.1 graph containers.
-This means the creation of named graphs used to isolate sets of data
+are defined as JSON-LD 1.1 graph containers.
+This means the creation of named graphs used to isolate sets of data
asserted by different entities. This ensures, for example, proper
cryptographic separation between the data graph provided by each issuer
and the one provided by the holder presenting the
@@ -5139,23 +5133,23 @@ -In addition to previously described privacy protections an issuer might use, -issuers need to also be aware of data they leak associated with identifiers -and claim types they use when issuing credentials. One example of this would -be an issuer issuing drivers licenses which reveal both the location(s) in -which they have jurisdiction and the location of the subject's residence. -Verifiers might take advantage of this by requesting a credential -to check that the subject is licensed to drive, when -in fact they are interested in metadata about the credential, such as which -issuer issued the credential, and tangential information that might have been -leaked by the issuer, such as the subject's home address. To mitigate such -leakage, issuers might choose to use common identifiers to mask specific -location information or other sensitive metadata; for example, a shared issuer -identifier at a state or nation level, instead of at the level of a county, city, town, or other smaller -municipality. Further, holder attestation mechanisms can be used by -verifiers to preserve privacy, by providing proofs that an issuer -exists in a set of trusted entities, without needing to disclose the exact -issuer. +In addition to previously described privacy protections an issuer might +use, issuers need to also be aware of data they leak associated with +identifiers and claim types they use when issuing credentials. One +example of this would be an issuer issuing drivers licenses which reveal +both the location(s) in which they have jurisdiction and the location of the +subject's residence. Verifiers might take advantage of this by +requesting a credential to check that the subject is licensed to +drive, when in fact they are interested in metadata about the +credential, such as which issuer issued the credential, and tangential +information that might have been leaked by the issuer, such as the +subject's home address. To mitigate such leakage, issuers might choose to +use common identifiers to mask specific location information or other sensitive +metadata; for example, a shared issuer identifier at a state or nation level, +instead of at the level of a county, city, town, or other smaller municipality. +Further, holder attestation mechanisms can be used by verifiers to +preserve privacy, by providing proofs that an issuer exists in a set of +trusted entities, without needing to disclose the exact issuer.
@@ -5237,12 +5231,13 @@Verifiable credentials often contain URLs to data that resides outside of the verifiable credential itself. Linked content that exists outside a -verifiable credential, such as images, JSON-LD Contexts, JSON Schemas, and -other machine-readable data, are often not protected against tampering because the -data resides outside of the protection of the -securing mechanism on the verifiable credential. -For example, the content retrievable by dereferencing the following highlighted -links is not integrity protected, but probably ought to be: +verifiable credential, such as images, JSON-LD Contexts, JSON Schemas, +and other machine-readable data, are often not protected against tampering +because the data resides outside of the protection of the +securing mechanism on the +verifiable credential. For example, the content retrievable by +dereferencing the following highlighted links is not integrity protected, but +probably ought to be:
Man-in-the-Middle (MITM) AttackReplay Attack
-A verifier might wish to ensure that a verifiable presentation is not used more than a -certain number of times. For example, a verifiable credential representing an event ticket, -might allow entry to multiple individuals if presented multiple times, undermining -the purpose of the ticket from the perspective of its issuer. To prevent against such attacks, +A verifier might wish to ensure that a verifiable presentation is +not used more than a certain number of times. For example, a verifiable +credential representing an event ticket, might allow entry to multiple +individuals if presented multiple times, undermining the purpose of the ticket +from the perspective of its issuer. To prevent against such attacks, holders can make use of techniques such as including a -nonce during presentation, -or adding an expiry timestamp to reduce the window of attack. +nonce during +presentation, or adding an expiry timestamp to reduce the window of attack.
Spoofing Attack
-A verifier has a vested interest in knowing that a holder is authorized -to present the claims inside of a verifiable presentation. While the data -model outlines the structure and data elements necessary for a verifiable credential, -it does not include a mechanism to ascertain the authorization of -presented credentials. To address this concern, implementers might need to explore -supplementary methods, such as binding verifiable credentials to strong -authentication mechanisms or using additional attributes in verifiable presentations +A verifier has a vested interest in knowing that a holder is +authorized to present the claims inside of a verifiable presentation. +While the data model outlines the structure and data elements necessary for a +verifiable credential, it does not include a mechanism to ascertain the +authorization of presented credentials. To address this concern, +implementers might need to explore supplementary methods, such as binding +verifiable credentials to strong authentication mechanisms or using +additional attributes in verifiable presentations to enable proof of control.
@@ -5474,14 +5471,15 @@Acceptable Use
Unauthorized Use
-Any attempt by entities to make use of verifiable credentials and verifiable presentations -outside of their intended use can be seen as unauthorized. One class of unauthorized -use is a confidentiality violation. Consider an example -where a holder shares a verifiable presentation with a verifier to establish -their age and residency status. If the verifier then proceeds to -exploit the holder's data without proper consent, such as by selling the -data to a data broker, that would constitute an unauthorized use of the data, violating -an expectation of privacy that the holder might have in the transaction. +Any attempt by entities to make use of verifiable credentials and +verifiable presentations outside of their intended use can be seen as +unauthorized. One class of unauthorized use is a confidentiality +violation. Consider an example where a holder shares a verifiable +presentation with a verifier to establish their age and residency +status. If the verifier then proceeds to exploit the holder's data +without proper consent, such as by selling the data to a data broker, that would +constitute an unauthorized use of the data, violating an expectation of privacy +that the holder might have in the transaction.
Similarly, an issuer could make use of a termsOfUse @@ -5794,7 +5792,8 @@
Holder
See the and - for additional examples related to subject and holder. + for additional examples related to +subject and holder.