adds credential ordering

src/ctap/data_formats.rs

@@ -500,6 +500,7 @@ pub struct PublicKeyCredentialSource {
     pub other_ui: Option<String>,
     pub cred_random: Option<Vec<u8>>,
     pub cred_protect_policy: Option<CredentialProtectionPolicy>,
+    pub creation_order: u64,
 }
 
 // We serialize credentials for the persistent storage using CBOR maps. Each field of a credential
@@ -512,6 +513,7 @@ enum PublicKeyCredentialSourceField {
     OtherUi = 4,
     CredRandom = 5,
     CredProtectPolicy = 6,
+    CreationOrder = 7,
     // When a field is removed, its tag should be reserved and not used for new fields. We document
     // those reserved tags below.
     // Reserved tags: none.
@@ -535,6 +537,7 @@ impl From<PublicKeyCredentialSource> for cbor::Value {
             PublicKeyCredentialSourceField::OtherUi => credential.other_ui,
             PublicKeyCredentialSourceField::CredRandom => credential.cred_random,
             PublicKeyCredentialSourceField::CredProtectPolicy => credential.cred_protect_policy,
+            PublicKeyCredentialSourceField::CreationOrder => credential.creation_order,
         }
     }
 }
@@ -552,6 +555,7 @@ impl TryFrom<cbor::Value> for PublicKeyCredentialSource {
                 PublicKeyCredentialSourceField::OtherUi => other_ui,
                 PublicKeyCredentialSourceField::CredRandom => cred_random,
                 PublicKeyCredentialSourceField::CredProtectPolicy => cred_protect_policy,
+                PublicKeyCredentialSourceField::CreationOrder => creation_order,
             } = extract_map(cbor_value)?;
         }
 
@@ -569,6 +573,7 @@ impl TryFrom<cbor::Value> for PublicKeyCredentialSource {
         let cred_protect_policy = cred_protect_policy
             .map(CredentialProtectionPolicy::try_from)
             .transpose()?;
+        let creation_order = creation_order.map(extract_unsigned).unwrap_or(Ok(0))?;
         // We don't return whether there were unknown fields in the CBOR value. This means that
         // deserialization is not injective. In particular deserialization is only an inverse of
         // serialization at a given version of OpenSK. This is not a problem because:
@@ -588,6 +593,7 @@ impl TryFrom<cbor::Value> for PublicKeyCredentialSource {
             other_ui,
             cred_random,
             cred_protect_policy,
+            creation_order,
         })
     }
 }
@@ -1357,6 +1363,7 @@ mod test {
             other_ui: None,
             cred_random: None,
             cred_protect_policy: None,
+            creation_order: 0,
         };
 
         assert_eq!(