Add multibase datatype definition

index.html

@@ -1936,7 +1936,14 @@ <h3>Securing Data Losslessly</h3>
         </section>
 
         <section>
-          <h3 id="cryptosuiteString">The `cryptosuiteString` Datatype</h3>
+          <h3>Datatypes</h3>
+
+          <p>
+This section defines datatypes that are used by this specification.
+          </p>
+
+        <section>
+          <h4 id="cryptosuiteString">The `cryptosuiteString` Datatype</h3>
 
           <p>
 This specification encodes cryptographic suite identifiers as enumerable
@@ -1981,6 +1988,50 @@ <h3 id="cryptosuiteString">The `cryptosuiteString` Datatype</h3>
           </dl>
         </section>
 
+        <section>
+          <h4 id="multibase">The `multibase` Datatype</h3>
+
+          <p>
+[[?MULTIBASE]]-encoded strings are used to encode binary data into ASCII-only
+formats, which are useful in environments that cannot directly represent binary
+values. This specification makes use of this encoding. In environments that
+support data types for string values, such as RDF [[?RDF-CONCEPTS]],
+[[?MULTIBASE]]-encoded content is indicated using a literal value whose datatype
+is set to `https://w3id.org/security#multibase`.
+          </p>
+
+          <p>
+The `multibase` datatype is defined as follows:
+          </p>
+
+          <dl>
+            <dt>The URL denoting this datatype</dt>
+            <dd>
+`https://w3id.org/security#multibase`
+            </dd>
+            <dt>The lexical space</dt>
+            <dd>
+Any string that starts with a [[?MULTIBASE]] character and the rest of
+the characters consist of allowable characters in the respective base-encoding
+alphabet.
+            </dd>
+            <dt>The value space</dt>
+            <dd>
+An arbitrary binary data value.
+            </dd>
+            <dt>The lexical-to-value mapping</dt>
+            <dd>
+Any element of the lexical space is mapped to the value space by base-decoding
+the value based on the base-decoding alphabet associated with the
+first  [[?MULTIBASE]] character in the lexical string.
+            </dd>
+            <dt>The canonical mapping</dt>
+            <dd>
+The canonical mapping consists of using the lexical-to-value mapping.
+            </dd>
+          </dl>
+        </section>
+
       </section>
 
     </section>

vocab/security/vocabulary.yml

@@ -169,7 +169,7 @@ property:
     label: Proof sets
     range: sec:ProofGraph
     defined_by: https://www.w3.org/TR/vc-data-integrity/#proof-sets
-    
+
   - id: domain
     label: Domain of a proof
     domain: sec:Proof
@@ -197,7 +197,7 @@ property:
   - id: proofValue
     label: Proof value
     domain: sec:Proof
-    range: xsd:string
+    range: sec:multibase
     defined_by: https://www.w3.org/TR/vc-data-integrity/#dfn-proofvalue
 
   - id: created
@@ -252,7 +252,7 @@ property:
   - id: publicKeyMultibase
     label: Public key multibase
     domain: sec:Multikey
-    range: xsd:string
+    range: sec:multibase
     defined_by: https://www.w3.org/TR/vc-data-integrity/#dfn-publickeymultibase
     see_also:
       - label: multibase
@@ -265,7 +265,7 @@ property:
   - id: secretKeyMultibase
     label: Secret key multibase
     domain: sec:Multikey
-    range: xsd:string
+    range: sec:multibase
     defined_by: https://www.w3.org/TR/vc-data-integrity/#dfn-secretkeymultibase
     see_also:
       - label: multibase format
@@ -436,7 +436,7 @@ individual:
     upper_value: sec:ProcessingError
     label: Invalid verification method
     defined_by: https://www.w3.org/TR/vc-data-integrity/#INVALID_VERIFICATION_METHOD
-    
+
   - id: INVALID_PROOF_PURPOSE_FOR_VERIFICATION_METHOD
     upper_value: sec:ProcessingError
     label: Invalid proof purpose for verification method
@@ -447,3 +447,8 @@ datatype:
     label: Datatype for cryptosuite Identifiers
     upper_value: xsd:string
     defined_by: https://www.w3.org/TR/vc-data-integrity/#cryptosuiteString
+
+  - id: multibase
+    label: Datatype for multibase values
+    upper_value: xsd:string
+    defined_by: https://www.w3.org/TR/vc-data-integrity/#multibase