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Update algorithms to align with new cryptosuite interface #144

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Mar 14, 2024
Merged

Update algorithms to align with new cryptosuite interface #144

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e6d98cb
Add cryptosuite instantiation algorithm.
msporny Mar 5, 2024
2c71d93
Add Create Base Proof to align w/ new cryptosuite interface.
msporny Mar 5, 2024
b0b5f6b
Update Verify Derived Proof to use new cryptosuite interface.
msporny Mar 5, 2024
6d18d0e
Fix grammar, syntax, and markup in cryptosuite interface.
msporny Mar 14, 2024
892868f
Fix formatting in verify derived proof.
msporny Mar 14, 2024
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196 changes: 142 additions & 54 deletions index.html
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Expand Up @@ -487,6 +487,45 @@ <h2>Algorithms</h2>
by default, and abort processing upon detection.
</p>

<section>
<h3>Instantiate Cryptosuite</h3>

<p>
This algorithm is used to configure a cryptographic suite to be used by the
<a data-cite="VC-DATA-INTEGRITY#add-proof">Add Proof</a> and
<a href="VC-DATA-INTEGRITY#verify-proof">Verify Proof</a>
functions in [[[VC-DATA-INTEGRITY]]]. The algorithm takes an options object
([=map=] |options|) as input and returns a [=data integrity cryptographic suite
instance|cryptosuite instance=] ([=struct=] |cryptosuite|).
</p>

<ol class="algorithm">
<li>
Initialize |cryptosuite| to an empty [=struct=].
</li>
<li>
If |options|.|type| does not equal `DataIntegrityProof`, return |cryptosuite|.
</li>
<li>
If |options|.|cryptosuite| is `bbs-2023` then:
<ol class="algorithm">
<li>
Set |cryptosuite|.|createProof| to the algorithm in Section
[[[#create-base-proof-bbs-2023]]].
</li>
<li>
Set |cryptosuite|.|verifyProof| to the algorithm in Section
[[[#verify-derived-proof-bbs-2023]]].
</li>
</ol>
</li>
<li>
Return |cryptosuite|.
</li>
</ol>

</section>

<section>
<h3>Selective Disclosure Functions</h3>

Expand Down Expand Up @@ -1052,24 +1091,49 @@ <h3>bbs-2023</h3>
</p>

<section>
<h4>Add Base Proof (bbs-2023)</h4>
<h4>Create Base Proof (bbs-2023)</h4>

<p>
To generate a base proof, the algorithm in
<a href="https://www.w3.org/TR/vc-data-integrity/#add-proof">
Section 4.1: Add Proof</a> of the Data Integrity
[[VC-DATA-INTEGRITY]] specification MUST be executed.
For that algorithm, the cryptographic suite specific
<a href="https://www.w3.org/TR/vc-data-integrity/#dfn-transformation-algorithm">
transformation algorithm</a> is defined in Section
<a href="#base-proof-transformation-bbs-2023"></a>, the
<a href="https://www.w3.org/TR/vc-data-integrity/#dfn-hashing-algorithm">
hashing algorithm</a> is defined in Section <a href="#base-proof-hashing-bbs-2023"></a>,
and the
<a href="https://www.w3.org/TR/vc-data-integrity/#dfn-proof-serialization-algorithm">
proof serialization algorithm</a> is defined in Section
<a href="#base-proof-serialization-bbs-2023"></a>.
The following algorithm specifies how to create a [=data integrity proof=] given
an <a>unsecured data document</a>. Required inputs are an
<a>unsecured data document</a> ([=map=] |unsecuredDocument|), and a set of proof
options ([=map=] |options|). A [=data integrity proof=] ([=map=]), or an error,
is produced as output.
</p>

<ol class="algorithm">
<li>
Let |proof| be a clone of the proof options, |options|.
</li>
<li>
Let |proofConfig| be the result of running the algorithm in
Section [[[#base-proof-configuration-bbs-2023]]] with
|options| passed as a parameter.
</li>
<li>
Let |transformedData| be the result of running the algorithm in Section
[[[#base-proof-transformation-bbs-2023]]] with |unsecuredDocument|,
|proofConfig|, and |options| passed as parameters.
</li>
<li>
Let |hashData| be the result of running the algorithm in Section
[[[#base-proof-hashing-bbs-2023]]] with |transformedData| and |proofConfig|
passed as a parameters.
</li>
<li>
Let |proofBytes| be the result of running the algorithm in Section
[[[#base-proof-serialization-bbs-2023]]] with |hashData| and
|options| passed as parameters.
</li>
<li>
Let |proof|.|proofValue| be a <a data-cite="VC-DATA-INTEGRITY#multibase-0">
base64url-encoded Multibase value</a> of the |proofBytes|.
</li>
<li>
Return |proof| as the [=data integrity proof=].
</li>
</ol>

</section>

<section>
Expand Down Expand Up @@ -1371,74 +1435,98 @@ <h4>Add Derived Proof (bbs-2023)</h4>

</section>


<section>
<h4>Verify Derived Proof (bbs-2023)</h4>

<p>
The following algorithm attempts verification of a `bbs-2023` derived
proof. This algorithm is called by a verifier of an BBS-protected
<a>verifiable credential</a>. The inputs include a JSON-LD document
(<var>document</var>), a BBS disclosure proof (<var>proof</var>), and any
custom JSON-LD API options (such as a document loader). A single boolean
<em>verification result</em> value is produced as output.
The following algorithm specifies how to verify a [=data integrity proof=] given
an <a>secured data document</a>. Required inputs are a
<a>secured data document</a> ([=map=] |securedDocument|). This algorithm returns
a <dfn>verification result</dfn>, which is a [=struct=] whose
[=struct/items=] are:
</p>

<dl>
<dt><dfn data-dfn-for="verification result">verified</dfn></dt>
<dd>`true` or `false`</dd>
<dt><dfn data-dfn-for="verification result">verifiedDocument</dfn></dt>
<dd>
<a data-cite="INFRA#nulls">Null</a>, if [=verification result/verified=] is
`false`; otherwise, an [=unsecured data document=]
</dd>
</dl>

<p>
To verify a derived proof, perform the following steps:
</p>

<ol class="algorithm">
<!-- [bbsProof, labelMapCompressed, mandatoryIndexes, adjSelectedIndexes] -->
<li>
Let |unsecuredDocument| be a copy of |securedDocument| with
the `proof` value removed.
</li>
<li>
Let |proofConfig| be a copy of |securedDocument|.|proof| with `proofValue`
removed.
</li>
<li>
Let |proof| be the value of |securedDocument|.|proof|.
</li>
<li>
Initialize `bbsProof`, `proofHash`, `mandatoryHash`, `selectedIndexes`,
`presentationHeader`, `pseudonym`, and `nonMandatory` to the values associated with their
property names in the object returned when calling the algorithm in Section
<a href="#createverifydata"></a>, passing the `document`, `proof`, and any
custom JSON-LD API options (such as a document loader).
`presentationHeader`, `pseudonym`, and `nonMandatory` to the values associated
with their property names in the object returned when calling the algorithm in
Section <a href="#createverifydata"></a>, passing the |unsecuredDocument|,
|proof|, and any custom JSON-LD API options (such as a document loader).
</li>
<li>
Initialize `bbsHeader` to the concatenation of `proofHash` and `mandatoryHash`
in that order. Initialize `disclosedMessages` to an array of byte arrays
obtained from the UTF-8 encoding of the elements of the `nonMandatory` array.
</li>
<li>
Initialize `verificationResult` to the result of applying the verification
Initialize |verified| to the result of applying the verification
algorithm below, depending on whether the |pseudonym| value is empty.
<ol class="algorithm">
<li>
If the |pseudonym| value is empty,
initialize `verificationResult` to the result of applying the verification
algorithm
`ProofVerify(PK, proof, header, ph, disclosed_messages, disclosed_indexes)` of
[[CFRG-BBS-SIGNATURE]]
with `PK` set as the public key of the original issuer, `proof` set as `bbsProof`,
`header` set as `bbsHeader`, `disclosed_messages` set as `disclosedMessages`,
`ph` set as `presentationHeader`, and `disclosed_indexes` set as
`selectiveIndexes`. Return `verificationResult` as <em>verification result</em>.
This applies to the regular BBS proof case as well as "anonymous holder binding"
If the |pseudonym| value is empty, initialize |verified| to the result of
applying the verification algorithm `ProofVerify(PK, proof, header, ph,
disclosed_messages, disclosed_indexes)` of [[CFRG-BBS-SIGNATURE]] with `PK` set
as the public key of the original issuer, `proof` set as `bbsProof`, `header`
set as `bbsHeader`, `disclosed_messages` set as `disclosedMessages`, `ph` set as
`presentationHeader`, and `disclosed_indexes` set as `selectiveIndexes`. This
applies to the regular BBS proof case as well as "anonymous holder binding"
case.
</li>
<li>
If the |pseudonym| value is not empty,
initialize `verificationResult` to the result of applying the verification
algorithm
`PseudonymProofVerify(PK, proof, header, ph, disclosed_messages, disclosed_indexes, pseudonym)`
of
[[CFRG-Pseudonym-BBS-Signature]],
with `PK` set as the public key of the original issuer, `proof` set as `bbsProof`,
`header` set as `bbsHeader`, `disclosed_messages` set as `disclosedMessages`,
`ph` set as `presentationHeader`, `disclosed_indexes` set as
`selectiveIndexes`, and `pseudonym`. Return `verificationResult` as
<em>verification result</em>.
This applies to the "pseudonym with issuer known pid" and "pseudonym with
hidden pid" cases.
If the |pseudonym| value is not empty, initialize |verified| to the result of
applying the verification algorithm `PseudonymProofVerify(PK, proof, header, ph,
disclosed_messages, disclosed_indexes, pseudonym)` of
[[CFRG-Pseudonym-BBS-Signature]], with `PK` set as the public key of the
original issuer, `proof` set as `bbsProof`, `header` set as `bbsHeader`,
`disclosed_messages` set as `disclosedMessages`, `ph` set as
`presentationHeader`, `disclosed_indexes` set as `selectiveIndexes`, and
`pseudonym`. This applies to the "pseudonym with issuer known pid" and
"pseudonym with hidden pid" cases.
</li>
</ol>

</li>
<li>
Return a [=verification result=] with [=struct/items=]:
<dl data-link-for="verification result">
<dt>[=verified=]</dt>
<dd>|verified|</dd>
<dt>[=verifiedDocument=]</dt>
<dd>
|unsecuredDocument| if |verified| is `true`, otherwise
<a data-cite="INFRA#nulls">Null</a>
</dd>
</dl>
</li>
</ol>

</section>

</section>

</section>
<section class="informative">
<h2>Optional Features</h2>
Expand Down
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