From f6d984403e37262d7cd1d664f6bda0d0f8f783cd Mon Sep 17 00:00:00 2001
From: Dana Keeler <dkeeler@mozilla.com>
Date: Tue, 19 Sep 2023 20:03:37 +0000
Subject: [PATCH] Bug 1823782 - implement webauthn serialization methods
 r=jschanck,webidl,saschanaz,tschuster

Differential Revision: https://phabricator.services.mozilla.com/D187239
---
 .../AuthenticatorAssertionResponse.cpp        |  52 +++
 dom/webauthn/AuthenticatorAssertionResponse.h |   3 +
 .../AuthenticatorAttestationResponse.cpp      | 120 ++++++-
 .../AuthenticatorAttestationResponse.h        |   6 +
 dom/webauthn/AuthenticatorResponse.cpp        |   1 +
 dom/webauthn/AuthenticatorResponse.h          |   4 +-
 dom/webauthn/PublicKeyCredential.cpp          | 214 ++++++++++++-
 dom/webauthn/PublicKeyCredential.h            |  23 +-
 dom/webauthn/WebAuthnManager.cpp              |   4 +-
 dom/webauthn/tests/mochitest.ini              |   2 +
 .../tests/test_webauthn_serialization.html    | 297 ++++++++++++++++++
 dom/webidl/WebAuthentication.webidl           | 118 +++++++
 12 files changed, 815 insertions(+), 29 deletions(-)
 create mode 100644 dom/webauthn/tests/test_webauthn_serialization.html

diff --git a/dom/webauthn/AuthenticatorAssertionResponse.cpp b/dom/webauthn/AuthenticatorAssertionResponse.cpp
index 8569b324214e..ff0c445e4061 100644
--- a/dom/webauthn/AuthenticatorAssertionResponse.cpp
+++ b/dom/webauthn/AuthenticatorAssertionResponse.cpp
@@ -4,6 +4,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
+#include "mozilla/Base64.h"
 #include "mozilla/dom/WebAuthenticationBinding.h"
 #include "mozilla/dom/AuthenticatorAssertionResponse.h"
 #include "mozilla/HoldDropJSObjects.h"
@@ -115,4 +116,55 @@ void AuthenticatorAssertionResponse::SetUserHandle(
   mUserHandle.Assign(aBuffer);
 }
 
+void AuthenticatorAssertionResponse::ToJSON(
+    AuthenticatorAssertionResponseJSON& aJSON, ErrorResult& aError) {
+  nsAutoCString clientDataJSONBase64;
+  nsresult rv = Base64URLEncode(
+      mClientDataJSON.Length(),
+      reinterpret_cast<const uint8_t*>(mClientDataJSON.get()),
+      mozilla::Base64URLEncodePaddingPolicy::Omit, clientDataJSONBase64);
+  // This will only fail if the length is so long that it overflows 32-bits
+  // when calculating the encoded size.
+  if (NS_FAILED(rv)) {
+    aError.ThrowDataError("clientDataJSON too long");
+    return;
+  }
+  aJSON.mClientDataJSON.Assign(NS_ConvertUTF8toUTF16(clientDataJSONBase64));
+
+  nsAutoCString authenticatorDataBase64;
+  rv = Base64URLEncode(
+      mAuthenticatorData.Length(), mAuthenticatorData.Elements(),
+      mozilla::Base64URLEncodePaddingPolicy::Omit, authenticatorDataBase64);
+  if (NS_FAILED(rv)) {
+    aError.ThrowDataError("authenticatorData too long");
+    return;
+  }
+  aJSON.mAuthenticatorData.Assign(
+      NS_ConvertUTF8toUTF16(authenticatorDataBase64));
+
+  nsAutoCString signatureBase64;
+  rv = Base64URLEncode(mSignature.Length(), mSignature.Elements(),
+                       mozilla::Base64URLEncodePaddingPolicy::Omit,
+                       signatureBase64);
+  if (NS_FAILED(rv)) {
+    aError.ThrowDataError("signature too long");
+    return;
+  }
+  aJSON.mSignature.Assign(NS_ConvertUTF8toUTF16(signatureBase64));
+
+  if (!mUserHandle.IsEmpty()) {
+    nsAutoCString userHandleBase64;
+    rv = Base64URLEncode(mUserHandle.Length(), mUserHandle.Elements(),
+                         mozilla::Base64URLEncodePaddingPolicy::Omit,
+                         userHandleBase64);
+    if (NS_FAILED(rv)) {
+      aError.ThrowDataError("userHandle too long");
+      return;
+    }
+    aJSON.mUserHandle.Construct(NS_ConvertUTF8toUTF16(userHandleBase64));
+  }
+
+  // attestationObject is not currently supported on assertion responses
+}
+
 }  // namespace mozilla::dom
diff --git a/dom/webauthn/AuthenticatorAssertionResponse.h b/dom/webauthn/AuthenticatorAssertionResponse.h
index 05d828b9ad46..75982800d135 100644
--- a/dom/webauthn/AuthenticatorAssertionResponse.h
+++ b/dom/webauthn/AuthenticatorAssertionResponse.h
@@ -11,6 +11,7 @@
 #include "mozilla/Attributes.h"
 #include "mozilla/dom/AuthenticatorResponse.h"
 #include "mozilla/dom/BindingDeclarations.h"
+#include "mozilla/dom/WebAuthenticationBinding.h"
 #include "nsCycleCollectionParticipant.h"
 #include "nsWrapperCache.h"
 
@@ -46,6 +47,8 @@ class AuthenticatorAssertionResponse final : public AuthenticatorResponse {
 
   void SetUserHandle(const nsTArray<uint8_t>& aBuffer);
 
+  void ToJSON(AuthenticatorAssertionResponseJSON& aJSON, ErrorResult& aError);
+
  private:
   nsTArray<uint8_t> mAuthenticatorData;
   JS::Heap<JSObject*> mAuthenticatorDataCachedObj;
diff --git a/dom/webauthn/AuthenticatorAttestationResponse.cpp b/dom/webauthn/AuthenticatorAttestationResponse.cpp
index c4094e763139..43f928f6566e 100644
--- a/dom/webauthn/AuthenticatorAttestationResponse.cpp
+++ b/dom/webauthn/AuthenticatorAttestationResponse.cpp
@@ -5,10 +5,10 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #include "AuthrsBridge_ffi.h"
-#include "mozilla/dom/WebAuthenticationBinding.h"
-#include "mozilla/dom/AuthenticatorAttestationResponse.h"
-
+#include "mozilla/Base64.h"
 #include "mozilla/HoldDropJSObjects.h"
+#include "mozilla/dom/AuthenticatorAttestationResponse.h"
+#include "mozilla/dom/WebAuthenticationBinding.h"
 
 namespace mozilla::dom {
 
@@ -79,21 +79,28 @@ void AuthenticatorAttestationResponse::SetTransports(
   mTransports.Assign(aTransports);
 }
 
-void AuthenticatorAttestationResponse::GetAuthenticatorData(
-    JSContext* aCx, JS::MutableHandle<JSObject*> aValue, ErrorResult& aRv) {
+nsresult AuthenticatorAttestationResponse::GetAuthenticatorDataBytes(
+    nsTArray<uint8_t>& aAuthenticatorData) {
   if (!mAttestationObjectParsed) {
     nsresult rv = authrs_webauthn_att_obj_constructor(
         mAttestationObject, /* anonymize */ false,
         getter_AddRefs(mAttestationObjectParsed));
     if (NS_FAILED(rv)) {
-      aRv.Throw(rv);
-      return;
+      return rv;
     }
   }
-
-  nsTArray<uint8_t> authenticatorData;
   nsresult rv =
-      mAttestationObjectParsed->GetAuthenticatorData(authenticatorData);
+      mAttestationObjectParsed->GetAuthenticatorData(aAuthenticatorData);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+  return NS_OK;
+}
+
+void AuthenticatorAttestationResponse::GetAuthenticatorData(
+    JSContext* aCx, JS::MutableHandle<JSObject*> aValue, ErrorResult& aRv) {
+  nsTArray<uint8_t> authenticatorData;
+  nsresult rv = GetAuthenticatorDataBytes(authenticatorData);
   if (NS_FAILED(rv)) {
     aRv.Throw(rv);
     return;
@@ -108,19 +115,27 @@ void AuthenticatorAttestationResponse::GetAuthenticatorData(
   aValue.set(buffer);
 }
 
-void AuthenticatorAttestationResponse::GetPublicKey(
-    JSContext* aCx, JS::MutableHandle<JSObject*> aValue, ErrorResult& aRv) {
+nsresult AuthenticatorAttestationResponse::GetPublicKeyBytes(
+    nsTArray<uint8_t>& aPublicKeyBytes) {
   if (!mAttestationObjectParsed) {
     nsresult rv = authrs_webauthn_att_obj_constructor(
-        mAttestationObject, false, getter_AddRefs(mAttestationObjectParsed));
+        mAttestationObject, /* anonymize */ false,
+        getter_AddRefs(mAttestationObjectParsed));
     if (NS_FAILED(rv)) {
-      aRv.Throw(rv);
-      return;
+      return rv;
     }
   }
+  nsresult rv = mAttestationObjectParsed->GetPublicKey(aPublicKeyBytes);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+  return NS_OK;
+}
 
+void AuthenticatorAttestationResponse::GetPublicKey(
+    JSContext* aCx, JS::MutableHandle<JSObject*> aValue, ErrorResult& aRv) {
   nsTArray<uint8_t> publicKey;
-  nsresult rv = mAttestationObjectParsed->GetPublicKey(publicKey);
+  nsresult rv = GetPublicKeyBytes(publicKey);
   if (NS_FAILED(rv)) {
     if (rv == NS_ERROR_NOT_AVAILABLE) {
       aValue.set(nullptr);
@@ -155,4 +170,77 @@ COSEAlgorithmIdentifier AuthenticatorAttestationResponse::GetPublicKeyAlgorithm(
   return alg;
 }
 
+void AuthenticatorAttestationResponse::ToJSON(
+    AuthenticatorAttestationResponseJSON& aJSON, ErrorResult& aError) {
+  nsAutoCString clientDataJSONBase64;
+  nsresult rv = Base64URLEncode(
+      mClientDataJSON.Length(),
+      reinterpret_cast<const uint8_t*>(mClientDataJSON.get()),
+      mozilla::Base64URLEncodePaddingPolicy::Omit, clientDataJSONBase64);
+  // This will only fail if the length is so long that it overflows 32-bits
+  // when calculating the encoded size.
+  if (NS_FAILED(rv)) {
+    aError.ThrowDataError("clientDataJSON too long");
+    return;
+  }
+  aJSON.mClientDataJSON.Assign(NS_ConvertUTF8toUTF16(clientDataJSONBase64));
+
+  nsTArray<uint8_t> authenticatorData;
+  rv = GetAuthenticatorDataBytes(authenticatorData);
+  if (NS_FAILED(rv)) {
+    aError.ThrowUnknownError("could not get authenticatorData");
+    return;
+  }
+  nsAutoCString authenticatorDataBase64;
+  rv = Base64URLEncode(authenticatorData.Length(), authenticatorData.Elements(),
+                       mozilla::Base64URLEncodePaddingPolicy::Omit,
+                       authenticatorDataBase64);
+  if (NS_FAILED(rv)) {
+    aError.ThrowDataError("authenticatorData too long");
+    return;
+  }
+  aJSON.mAuthenticatorData.Assign(
+      NS_ConvertUTF8toUTF16(authenticatorDataBase64));
+
+  if (!aJSON.mTransports.Assign(mTransports, mozilla::fallible)) {
+    aError.Throw(NS_ERROR_OUT_OF_MEMORY);
+    return;
+  }
+
+  nsTArray<uint8_t> publicKeyBytes;
+  rv = GetPublicKeyBytes(publicKeyBytes);
+  if (NS_SUCCEEDED(rv)) {
+    nsAutoCString publicKeyBytesBase64;
+    rv = Base64URLEncode(publicKeyBytes.Length(), publicKeyBytes.Elements(),
+                         mozilla::Base64URLEncodePaddingPolicy::Omit,
+                         publicKeyBytesBase64);
+    if (NS_FAILED(rv)) {
+      aError.ThrowDataError("publicKey too long");
+      return;
+    }
+    aJSON.mPublicKey.Construct(NS_ConvertUTF8toUTF16(publicKeyBytesBase64));
+  } else if (rv != NS_ERROR_NOT_AVAILABLE) {
+    aError.ThrowUnknownError("could not get publicKey");
+    return;
+  }
+
+  COSEAlgorithmIdentifier publicKeyAlgorithm = GetPublicKeyAlgorithm(aError);
+  if (aError.Failed()) {
+    aError.ThrowUnknownError("could not get publicKeyAlgorithm");
+    return;
+  }
+  aJSON.mPublicKeyAlgorithm = publicKeyAlgorithm;
+
+  nsAutoCString attestationObjectBase64;
+  rv = Base64URLEncode(
+      mAttestationObject.Length(), mAttestationObject.Elements(),
+      mozilla::Base64URLEncodePaddingPolicy::Omit, attestationObjectBase64);
+  if (NS_FAILED(rv)) {
+    aError.ThrowDataError("attestationObject too long");
+    return;
+  }
+  aJSON.mAttestationObject.Assign(
+      NS_ConvertUTF8toUTF16(attestationObjectBase64));
+}
+
 }  // namespace mozilla::dom
diff --git a/dom/webauthn/AuthenticatorAttestationResponse.h b/dom/webauthn/AuthenticatorAttestationResponse.h
index 356da50825d5..da559ffd0e10 100644
--- a/dom/webauthn/AuthenticatorAttestationResponse.h
+++ b/dom/webauthn/AuthenticatorAttestationResponse.h
@@ -11,6 +11,7 @@
 #include "mozilla/Attributes.h"
 #include "mozilla/dom/AuthenticatorResponse.h"
 #include "mozilla/dom/BindingDeclarations.h"
+#include "mozilla/dom/WebAuthenticationBinding.h"
 #include "nsCycleCollectionParticipant.h"
 #include "nsIWebAuthnController.h"
 #include "nsWrapperCache.h"
@@ -49,7 +50,12 @@ class AuthenticatorAttestationResponse final : public AuthenticatorResponse {
 
   COSEAlgorithmIdentifier GetPublicKeyAlgorithm(ErrorResult& aRv);
 
+  void ToJSON(AuthenticatorAttestationResponseJSON& aJSON, ErrorResult& aError);
+
  private:
+  nsresult GetAuthenticatorDataBytes(nsTArray<uint8_t>& aAuthenticatorData);
+  nsresult GetPublicKeyBytes(nsTArray<uint8_t>& aPublicKeyBytes);
+
   nsTArray<uint8_t> mAttestationObject;
   nsCOMPtr<nsIWebAuthnAttObj> mAttestationObjectParsed;
   JS::Heap<JSObject*> mAttestationObjectCachedObj;
diff --git a/dom/webauthn/AuthenticatorResponse.cpp b/dom/webauthn/AuthenticatorResponse.cpp
index 579a3a0ca2eb..ba291ae4cdf4 100644
--- a/dom/webauthn/AuthenticatorResponse.cpp
+++ b/dom/webauthn/AuthenticatorResponse.cpp
@@ -4,6 +4,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
+#include "mozilla/Base64.h"
 #include "mozilla/dom/AuthenticatorResponse.h"
 #include "mozilla/dom/TypedArray.h"
 #include "nsPIDOMWindow.h"
diff --git a/dom/webauthn/AuthenticatorResponse.h b/dom/webauthn/AuthenticatorResponse.h
index 35d7f010d864..b0abb3185ca4 100644
--- a/dom/webauthn/AuthenticatorResponse.h
+++ b/dom/webauthn/AuthenticatorResponse.h
@@ -38,9 +38,11 @@ class AuthenticatorResponse : public nsISupports, public nsWrapperCache {
 
   void SetClientDataJSON(const nsCString& aBuffer);
 
+ protected:
+  nsCString mClientDataJSON;
+
  private:
   nsCOMPtr<nsPIDOMWindowInner> mParent;
-  nsCString mClientDataJSON;
   JS::Heap<JSObject*> mClientDataJSONCachedObj;
 };
 
diff --git a/dom/webauthn/PublicKeyCredential.cpp b/dom/webauthn/PublicKeyCredential.cpp
index bfeafff0e193..f35f326bfb82 100644
--- a/dom/webauthn/PublicKeyCredential.cpp
+++ b/dom/webauthn/PublicKeyCredential.cpp
@@ -4,13 +4,16 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
+#include "mozilla/Base64.h"
+#include "mozilla/HoldDropJSObjects.h"
+#include "mozilla/Preferences.h"
+#include "mozilla/StaticPrefs_security.h"
+#include "mozilla/dom/AuthenticatorResponse.h"
+#include "mozilla/dom/ChromeUtils.h"
 #include "mozilla/dom/Promise.h"
 #include "mozilla/dom/PublicKeyCredential.h"
 #include "mozilla/dom/WebAuthenticationBinding.h"
 #include "nsCycleCollectionParticipant.h"
-#include "mozilla/dom/AuthenticatorResponse.h"
-#include "mozilla/HoldDropJSObjects.h"
-#include "mozilla/StaticPrefs_security.h"
 
 #ifdef XP_WIN
 #  include "WinWebAuthnManager.h"
@@ -36,7 +39,8 @@ NS_IMPL_CYCLE_COLLECTION_TRACE_END
 
 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_INHERITED(PublicKeyCredential,
                                                   Credential)
-  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mResponse)
+  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mAttestationResponse)
+  NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mAssertionResponse)
 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
 
 NS_IMPL_ADDREF_INHERITED(PublicKeyCredential, Credential)
@@ -72,16 +76,27 @@ void PublicKeyCredential::GetRawId(JSContext* aCx,
 }
 
 already_AddRefed<AuthenticatorResponse> PublicKeyCredential::Response() const {
-  RefPtr<AuthenticatorResponse> temp(mResponse);
-  return temp.forget();
+  if (mAttestationResponse) {
+    return do_AddRef(mAttestationResponse);
+  }
+  if (mAssertionResponse) {
+    return do_AddRef(mAssertionResponse);
+  }
+  return nullptr;
 }
 
 void PublicKeyCredential::SetRawId(const nsTArray<uint8_t>& aBuffer) {
   mRawId.Assign(aBuffer);
 }
 
-void PublicKeyCredential::SetResponse(RefPtr<AuthenticatorResponse> aResponse) {
-  mResponse = aResponse;
+void PublicKeyCredential::SetAttestationResponse(
+    const RefPtr<AuthenticatorAttestationResponse>& aAttestationResponse) {
+  mAttestationResponse = aAttestationResponse;
+}
+
+void PublicKeyCredential::SetAssertionResponse(
+    const RefPtr<AuthenticatorAssertionResponse>& aAssertionResponse) {
+  mAssertionResponse = aAssertionResponse;
 }
 
 /* static */
@@ -160,6 +175,54 @@ void PublicKeyCredential::GetClientExtensionResults(
   aResult = mClientExtensionOutputs;
 }
 
+void PublicKeyCredential::ToJSON(JSContext* aCx,
+                                 JS::MutableHandle<JSObject*> aRetval,
+                                 ErrorResult& aError) {
+  JS::Rooted<JS::Value> value(aCx);
+  if (mAttestationResponse) {
+    RegistrationResponseJSON json;
+    GetId(json.mId);
+    GetId(json.mRawId);
+    mAttestationResponse->ToJSON(json.mResponse, aError);
+    if (aError.Failed()) {
+      return;
+    }
+    // TODO(bug 1810851): authenticatorAttachment
+    if (mClientExtensionOutputs.mHmacCreateSecret.WasPassed()) {
+      json.mClientExtensionResults.mHmacCreateSecret.Construct(
+          mClientExtensionOutputs.mHmacCreateSecret.Value());
+    }
+    json.mType.Assign(u"public-key"_ns);
+    if (!ToJSValue(aCx, json, &value)) {
+      aError.StealExceptionFromJSContext(aCx);
+      return;
+    }
+  } else if (mAssertionResponse) {
+    AuthenticationResponseJSON json;
+    GetId(json.mId);
+    GetId(json.mRawId);
+    mAssertionResponse->ToJSON(json.mResponse, aError);
+    if (aError.Failed()) {
+      return;
+    }
+    // TODO(bug 1810851): authenticatorAttachment
+    if (mClientExtensionOutputs.mAppid.WasPassed()) {
+      json.mClientExtensionResults.mAppid.Construct(
+          mClientExtensionOutputs.mAppid.Value());
+    }
+    json.mType.Assign(u"public-key"_ns);
+    if (!ToJSValue(aCx, json, &value)) {
+      aError.StealExceptionFromJSContext(aCx);
+      return;
+    }
+  } else {
+    MOZ_ASSERT_UNREACHABLE(
+        "either mAttestationResponse or mAssertionResponse should be set");
+  }
+  JS::Rooted<JSObject*> result(aCx, &value.toObject());
+  aRetval.set(result);
+}
+
 void PublicKeyCredential::SetClientExtensionResultAppId(bool aResult) {
   mClientExtensionOutputs.mAppid.Construct();
   mClientExtensionOutputs.mAppid.Value() = aResult;
@@ -171,4 +234,139 @@ void PublicKeyCredential::SetClientExtensionResultHmacSecret(
   mClientExtensionOutputs.mHmacCreateSecret.Value() = aHmacCreateSecret;
 }
 
+bool Base64DecodeToArrayBuffer(GlobalObject& aGlobal, const nsAString& aString,
+                               ArrayBuffer& aArrayBuffer, ErrorResult& aRv) {
+  JSContext* cx = aGlobal.Context();
+  JS::Rooted<JSObject*> result(cx);
+  Base64URLDecodeOptions options;
+  options.mPadding = Base64URLDecodePadding::Ignore;
+  mozilla::dom::ChromeUtils::Base64URLDecode(
+      aGlobal, NS_ConvertUTF16toUTF8(aString), options, &result, aRv);
+  if (aRv.Failed()) {
+    return false;
+  }
+  return aArrayBuffer.Init(result);
+}
+
+void PublicKeyCredential::ParseCreationOptionsFromJSON(
+    GlobalObject& aGlobal,
+    const PublicKeyCredentialCreationOptionsJSON& aOptions,
+    PublicKeyCredentialCreationOptions& aResult, ErrorResult& aRv) {
+  if (aOptions.mRp.mId.WasPassed()) {
+    aResult.mRp.mId.Construct(aOptions.mRp.mId.Value());
+  }
+  aResult.mRp.mName.Assign(aOptions.mRp.mName);
+
+  aResult.mUser.mName.Assign(aOptions.mUser.mName);
+  if (!Base64DecodeToArrayBuffer(aGlobal, aOptions.mUser.mId,
+                                 aResult.mUser.mId.SetAsArrayBuffer(), aRv)) {
+    aRv.ThrowEncodingError("could not decode user ID as urlsafe base64");
+    return;
+  }
+  aResult.mUser.mDisplayName.Assign(aOptions.mUser.mDisplayName);
+
+  if (!Base64DecodeToArrayBuffer(aGlobal, aOptions.mChallenge,
+                                 aResult.mChallenge.SetAsArrayBuffer(), aRv)) {
+    aRv.ThrowEncodingError("could not decode challenge as urlsafe base64");
+    return;
+  }
+
+  aResult.mPubKeyCredParams = aOptions.mPubKeyCredParams;
+
+  if (aOptions.mTimeout.WasPassed()) {
+    aResult.mTimeout.Construct(aOptions.mTimeout.Value());
+  }
+
+  for (const auto& excludeCredentialJSON : aOptions.mExcludeCredentials) {
+    PublicKeyCredentialDescriptor* excludeCredential =
+        aResult.mExcludeCredentials.AppendElement(fallible);
+    if (!excludeCredential) {
+      aRv.Throw(NS_ERROR_OUT_OF_MEMORY);
+      return;
+    }
+    excludeCredential->mType = excludeCredentialJSON.mType;
+    if (!Base64DecodeToArrayBuffer(aGlobal, excludeCredentialJSON.mId,
+                                   excludeCredential->mId.SetAsArrayBuffer(),
+                                   aRv)) {
+      aRv.ThrowEncodingError(
+          "could not decode excluded credential ID as urlsafe base64");
+      return;
+    }
+    if (excludeCredentialJSON.mTransports.WasPassed()) {
+      excludeCredential->mTransports.Construct(
+          excludeCredentialJSON.mTransports.Value());
+    }
+  }
+
+  if (aOptions.mAuthenticatorSelection.WasPassed()) {
+    aResult.mAuthenticatorSelection = aOptions.mAuthenticatorSelection.Value();
+  }
+
+  aResult.mAttestation = aOptions.mAttestation;
+
+  if (aOptions.mExtensions.WasPassed()) {
+    if (aOptions.mExtensions.Value().mAppid.WasPassed()) {
+      aResult.mExtensions.mAppid.Construct(
+          aOptions.mExtensions.Value().mAppid.Value());
+    }
+    if (aOptions.mExtensions.Value().mHmacCreateSecret.WasPassed()) {
+      aResult.mExtensions.mHmacCreateSecret.Construct(
+          aOptions.mExtensions.Value().mHmacCreateSecret.Value());
+    }
+  }
+}
+
+void PublicKeyCredential::ParseRequestOptionsFromJSON(
+    GlobalObject& aGlobal,
+    const PublicKeyCredentialRequestOptionsJSON& aOptions,
+    PublicKeyCredentialRequestOptions& aResult, ErrorResult& aRv) {
+  if (!Base64DecodeToArrayBuffer(aGlobal, aOptions.mChallenge,
+                                 aResult.mChallenge.SetAsArrayBuffer(), aRv)) {
+    aRv.ThrowEncodingError("could not decode challenge as urlsafe base64");
+    return;
+  }
+
+  if (aOptions.mTimeout.WasPassed()) {
+    aResult.mTimeout.Construct(aOptions.mTimeout.Value());
+  }
+
+  if (aOptions.mRpId.WasPassed()) {
+    aResult.mRpId.Construct(aOptions.mRpId.Value());
+  }
+
+  for (const auto& allowCredentialJSON : aOptions.mAllowCredentials) {
+    PublicKeyCredentialDescriptor* allowCredential =
+        aResult.mAllowCredentials.AppendElement(fallible);
+    if (!allowCredential) {
+      aRv.Throw(NS_ERROR_OUT_OF_MEMORY);
+      return;
+    }
+    allowCredential->mType = allowCredentialJSON.mType;
+    if (!Base64DecodeToArrayBuffer(aGlobal, allowCredentialJSON.mId,
+                                   allowCredential->mId.SetAsArrayBuffer(),
+                                   aRv)) {
+      aRv.ThrowEncodingError(
+          "could not decode allowed credential ID as urlsafe base64");
+      return;
+    }
+    if (allowCredentialJSON.mTransports.WasPassed()) {
+      allowCredential->mTransports.Construct(
+          allowCredentialJSON.mTransports.Value());
+    }
+  }
+
+  aResult.mUserVerification = aOptions.mUserVerification;
+
+  if (aOptions.mExtensions.WasPassed()) {
+    if (aOptions.mExtensions.Value().mAppid.WasPassed()) {
+      aResult.mExtensions.mAppid.Construct(
+          aOptions.mExtensions.Value().mAppid.Value());
+    }
+    if (aOptions.mExtensions.Value().mHmacCreateSecret.WasPassed()) {
+      aResult.mExtensions.mHmacCreateSecret.Construct(
+          aOptions.mExtensions.Value().mHmacCreateSecret.Value());
+    }
+  }
+}
+
 }  // namespace mozilla::dom
diff --git a/dom/webauthn/PublicKeyCredential.h b/dom/webauthn/PublicKeyCredential.h
index d44dc4d7b6ab..d6963827c9c8 100644
--- a/dom/webauthn/PublicKeyCredential.h
+++ b/dom/webauthn/PublicKeyCredential.h
@@ -9,6 +9,8 @@
 
 #include "js/TypeDecls.h"
 #include "mozilla/Attributes.h"
+#include "mozilla/dom/AuthenticatorAssertionResponse.h"
+#include "mozilla/dom/AuthenticatorAttestationResponse.h"
 #include "mozilla/dom/BindingDeclarations.h"
 #include "mozilla/dom/Credential.h"
 #include "nsCycleCollectionParticipant.h"
@@ -38,7 +40,10 @@ class PublicKeyCredential final : public Credential {
 
   void SetRawId(const nsTArray<uint8_t>& aBuffer);
 
-  void SetResponse(RefPtr<AuthenticatorResponse>);
+  void SetAttestationResponse(
+      const RefPtr<AuthenticatorAttestationResponse>& aAttestationResponse);
+  void SetAssertionResponse(
+      const RefPtr<AuthenticatorAssertionResponse>& aAssertionResponse);
 
   static already_AddRefed<Promise>
   IsUserVerifyingPlatformAuthenticatorAvailable(GlobalObject& aGlobal,
@@ -50,14 +55,28 @@ class PublicKeyCredential final : public Credential {
   void GetClientExtensionResults(
       AuthenticationExtensionsClientOutputs& aResult);
 
+  void ToJSON(JSContext* aCx, JS::MutableHandle<JSObject*> aRetval,
+              ErrorResult& aError);
+
   void SetClientExtensionResultAppId(bool aResult);
 
   void SetClientExtensionResultHmacSecret(bool aHmacCreateSecret);
 
+  static void ParseCreationOptionsFromJSON(
+      GlobalObject& aGlobal,
+      const PublicKeyCredentialCreationOptionsJSON& aOptions,
+      PublicKeyCredentialCreationOptions& aResult, ErrorResult& aRv);
+
+  static void ParseRequestOptionsFromJSON(
+      GlobalObject& aGlobal,
+      const PublicKeyCredentialRequestOptionsJSON& aOptions,
+      PublicKeyCredentialRequestOptions& aResult, ErrorResult& aRv);
+
  private:
   nsTArray<uint8_t> mRawId;
   JS::Heap<JSObject*> mRawIdCachedObj;
-  RefPtr<AuthenticatorResponse> mResponse;
+  RefPtr<AuthenticatorAttestationResponse> mAttestationResponse;
+  RefPtr<AuthenticatorAssertionResponse> mAssertionResponse;
   AuthenticationExtensionsClientOutputs mClientExtensionOutputs;
 };
 
diff --git a/dom/webauthn/WebAuthnManager.cpp b/dom/webauthn/WebAuthnManager.cpp
index 4f0e97eca3fa..38538ff08454 100644
--- a/dom/webauthn/WebAuthnManager.cpp
+++ b/dom/webauthn/WebAuthnManager.cpp
@@ -717,7 +717,7 @@ void WebAuthnManager::FinishMakeCredential(
   credential->SetId(NS_ConvertASCIItoUTF16(keyHandleBase64Url));
   credential->SetType(u"public-key"_ns);
   credential->SetRawId(aResult.KeyHandle());
-  credential->SetResponse(attestation);
+  credential->SetAttestationResponse(attestation);
 
   // Forward client extension results.
   for (const auto& ext : aResult.Extensions()) {
@@ -765,7 +765,7 @@ void WebAuthnManager::FinishGetAssertion(
   credential->SetId(NS_ConvertASCIItoUTF16(keyHandleBase64Url));
   credential->SetType(u"public-key"_ns);
   credential->SetRawId(aResult.KeyHandle());
-  credential->SetResponse(assertion);
+  credential->SetAssertionResponse(assertion);
 
   // Forward client extension results.
   for (const auto& ext : aResult.Extensions()) {
diff --git a/dom/webauthn/tests/mochitest.ini b/dom/webauthn/tests/mochitest.ini
index 5321468a5397..d0fb118297c8 100644
--- a/dom/webauthn/tests/mochitest.ini
+++ b/dom/webauthn/tests/mochitest.ini
@@ -88,6 +88,8 @@ skip-if =
   win10_2004 # Bug 1718296 (Windows 10 1903+ has its own window and U2F that we cannot control with tests.)
   win10_2009 # Bug 1718296 (Windows 10 1903+ has its own window and U2F that we cannot control with tests.)
   win11_2009 # Bug 1718296 (Windows 10 1903+ has its own window and U2F that we cannot control with tests.)
+[test_webauthn_serialization.html]
+fail-if = xorigin
 [test_webauthn_store_credential.html]
 fail-if = xorigin # NotAllowedError
 skip-if =
diff --git a/dom/webauthn/tests/test_webauthn_serialization.html b/dom/webauthn/tests/test_webauthn_serialization.html
new file mode 100644
index 000000000000..ed8c4cdccd1e
--- /dev/null
+++ b/dom/webauthn/tests/test_webauthn_serialization.html
@@ -0,0 +1,297 @@
+<!DOCTYPE html>
+<meta charset=utf-8>
+<head>
+  <title>Tests W3C Web Authentication Data Types Serialization</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <script type="text/javascript" src="u2futil.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
+</head>
+<body>
+
+  <h1>Tests W3C Web Authentication Data Types Serialization</h1>
+  <a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1823782">Mozilla Bug 1823782</a>
+
+  <script class="testbody" type="text/javascript">
+    "use strict";
+
+    const { Assert } = SpecialPowers.ChromeUtils.importESModule(
+      "resource://testing-common/Assert.sys.mjs"
+    );
+
+    function arrayBufferEqualsArray(actual, expected, description) {
+      ok(actual instanceof ArrayBuffer, `${description} (actual should be array)`);
+      ok(expected instanceof Array, `${description} (expected should be array)`);
+      is(actual.byteLength, expected.length, `${description} (actual and expected should have same length)`);
+      let actualView = new Uint8Array(actual);
+      for (let i = 0; i < actualView.length; i++) {
+        if (actualView[i] != expected[i]) {
+          throw new Error(`actual and expected differ in byte ${i}: ${actualView[i]} vs ${expected[i]}`);
+        }
+      }
+      ok(true, description);
+    }
+
+    function isEmptyArray(arr, description) {
+      ok(arr instanceof Array, `${description} (expecting Array)`);
+      is(arr.length, 0, `${description} (array should be empty)`);
+    }
+
+    function shouldThrow(func, expectedError, description) {
+      let threw = false;
+      try {
+        func();
+      } catch (e) {
+        is(e.message, expectedError);
+        threw = true;
+      }
+      ok(threw, description);
+    }
+
+    add_task(function test_parseCreationOptionsFromJSON_minimal() {
+      let creationOptionsJSON = {
+        rp: { name: "Example" },
+        user: { id: "-l3qNLTKJng", name: "username", displayName: "display name" },
+        challenge: "XNJTTB3kfqk",
+        pubKeyCredParams: [],
+      };
+      let creationOptions = PublicKeyCredential.parseCreationOptionsFromJSON(creationOptionsJSON);
+      is(Object.getOwnPropertyNames(creationOptions).length, 8, "creation options should have 8 properties");
+      is(creationOptions.rp.id, undefined, "rp.id should be undefined");
+      is(creationOptions.rp.name, "Example", "rp.name should be Example");
+      arrayBufferEqualsArray(creationOptions.user.id, [ 250, 93, 234, 52, 180, 202, 38, 120 ], "user.id should be as expected");
+      is(creationOptions.user.displayName, "display name", "user.displayName should be 'display name'");
+      is(creationOptions.user.name, "username", "user.name should be username");
+      arrayBufferEqualsArray(creationOptions.challenge, [ 92, 210, 83, 76, 29, 228, 126, 169 ], "challenge should be as expected");
+      isEmptyArray(creationOptions.pubKeyCredParams, "pubKeyCredParams should be an empty array");
+      is(creationOptions.timeout, undefined, "timeout should be undefined");
+      isEmptyArray(creationOptions.excludeCredentials, "excludeCredentials should be an empty array");
+      is(creationOptions.authenticatorSelection.authenticatorAttachment, undefined, "authenticatorSelection.authenticatorAttachment should be undefined");
+      is(creationOptions.authenticatorSelection.residentKey, undefined, "creationOptions.authenticatorSelection.residentKey should be undefined");
+      is(creationOptions.authenticatorSelection.requireResidentKey, false, "creationOptions.authenticatorSelection.requireResidentKey should be false");
+      is(creationOptions.authenticatorSelection.userVerification, "preferred", "creationOptions.authenticatorSelection.userVerification should be preferred");
+      is(creationOptions.attestation, "none", "attestation should be none");
+      is(Object.getOwnPropertyNames(creationOptions.extensions).length, 0, "extensions should be an empty object");
+    });
+
+    add_task(function test_parseCreationOptionsFromJSON() {
+      let creationOptionsJSON = {
+        rp: { name: "Example", id: "example.com" },
+        user: { id: "19TVpqBBOAM", name: "username2", displayName: "another display name" },
+        challenge: "dR82FeUh5q4",
+        pubKeyCredParams: [{ type: "public-key", alg: -7 }],
+        timeout: 20000,
+        excludeCredentials: [{ type: "public-key", id: "TeM2k_di7Dk", transports: [ "usb" ]}],
+        authenticatorSelection: { authenticatorAttachment: "platform", residentKey: "required", requireResidentKey: true, userVerification: "discouraged" },
+        hints: ["hybrid"],
+        attestation: "indirect",
+        attestationFormats: ["fido-u2f"],
+        extensions: { appid: "https://www.example.com/appID", hmacCreateSecret: true },
+      };
+      let creationOptions = PublicKeyCredential.parseCreationOptionsFromJSON(creationOptionsJSON);
+      is(Object.getOwnPropertyNames(creationOptions).length, 9, "creation options should have 9 properties");
+      is(creationOptions.rp.name, "Example", "rp.name should be Example");
+      is(creationOptions.rp.id, "example.com", "rp.id should be example.com");
+      arrayBufferEqualsArray(creationOptions.user.id, [ 215, 212, 213, 166, 160, 65, 56, 3 ], "user.id should be as expected");
+      is(creationOptions.user.displayName, "another display name", "user.displayName should be 'another display name'");
+      is(creationOptions.user.name, "username2", "user.name should be username2");
+      arrayBufferEqualsArray(creationOptions.challenge, [ 117, 31, 54, 21, 229, 33, 230, 174 ], "challenge should be as expected");
+      is(creationOptions.pubKeyCredParams.length, 1, "pubKeyCredParams should have one element");
+      is(creationOptions.pubKeyCredParams[0].type, "public-key", "pubKeyCredParams[0].type should be public-key");
+      is(creationOptions.pubKeyCredParams[0].alg, -7, "pubKeyCredParams[0].alg should be -7");
+      is(creationOptions.timeout, 20000, "timeout should be 20000");
+      is(creationOptions.excludeCredentials.length, 1, "excludeCredentials should have one element");
+      is(creationOptions.excludeCredentials[0].type, "public-key", "excludeCredentials[0].type should be public-key");
+      arrayBufferEqualsArray(creationOptions.excludeCredentials[0].id, [ 77, 227, 54, 147, 247, 98, 236, 57 ], "excludeCredentials[0].id should be as expected");
+      is(creationOptions.excludeCredentials[0].transports.length, 1, "excludeCredentials[0].transports should have one element");
+      is(creationOptions.excludeCredentials[0].transports[0], "usb", "excludeCredentials[0].transports[0] should be usb");
+      is(creationOptions.authenticatorSelection.authenticatorAttachment, "platform", "authenticatorSelection.authenticatorAttachment should be platform");
+      is(creationOptions.authenticatorSelection.residentKey, "required", "creationOptions.authenticatorSelection.residentKey should be required");
+      is(creationOptions.authenticatorSelection.requireResidentKey, true, "creationOptions.authenticatorSelection.requireResidentKey should be true");
+      is(creationOptions.authenticatorSelection.userVerification, "discouraged", "creationOptions.authenticatorSelection.userVerification should be discouraged");
+      is(creationOptions.attestation, "indirect", "attestation should be indirect");
+      is(creationOptions.extensions.appid, "https://www.example.com/appID", "extensions.appid should be https://www.example.com/appID");
+      is(creationOptions.extensions.hmacCreateSecret, true, "extensions.hmacCreateSecret should be true");
+    });
+
+    add_task(function test_parseCreationOptionsFromJSON_malformed() {
+      let userIdNotBase64 = {
+        rp: { name: "Example" },
+        user: { id: "/not urlsafe base64+", name: "username", displayName: "display name" },
+        challenge: "XNJTTB3kfqk",
+        pubKeyCredParams: [],
+      };
+      shouldThrow(
+        () => { PublicKeyCredential.parseCreationOptionsFromJSON(userIdNotBase64); },
+        "PublicKeyCredential.parseCreationOptionsFromJSON: could not decode user ID as urlsafe base64",
+        "should get encoding error if user.id is not urlsafe base64"
+      );
+
+      let challengeNotBase64 = {
+        rp: { name: "Example" },
+        user: { id: "-l3qNLTKJng", name: "username", displayName: "display name" },
+        challenge: "this is not urlsafe base64!",
+        pubKeyCredParams: [],
+      };
+      shouldThrow(
+        () => { PublicKeyCredential.parseCreationOptionsFromJSON(challengeNotBase64); },
+        "PublicKeyCredential.parseCreationOptionsFromJSON: could not decode challenge as urlsafe base64",
+        "should get encoding error if challenge is not urlsafe base64"
+      );
+
+      let excludeCredentialsIdNotBase64 = {
+        rp: { name: "Example", id: "example.com" },
+        user: { id: "-l3qNLTKJng", name: "username", displayName: "display name" },
+        challenge: "dR82FeUh5q4",
+        pubKeyCredParams: [{ type: "public-key", alg: -7 }],
+        timeout: 20000,
+        excludeCredentials: [{ type: "public-key", id: "@#$%&^", transports: [ "usb" ]}],
+        authenticatorselection: { authenticatorattachment: "platform", residentkey: "required", requireresidentkey: true, userverification: "discouraged" },
+        hints: ["hybrid"],
+        attestation: "indirect",
+        attestationformats: ["fido-u2f"],
+        extensions: { appid: "https://www.example.com/appid", hmaccreatesecret: true },
+      };
+      shouldThrow(
+        () => { PublicKeyCredential.parseCreationOptionsFromJSON(excludeCredentialsIdNotBase64); },
+        "PublicKeyCredential.parseCreationOptionsFromJSON: could not decode excluded credential ID as urlsafe base64",
+        "should get encoding error if excludeCredentials[0].id is not urlsafe base64"
+      );
+    });
+
+    add_task(function test_parseRequestOptionsFromJSON_minimal() {
+      let requestOptionsJSON = {
+        challenge: "3yW2WHD_jbU",
+      };
+      let requestOptions = PublicKeyCredential.parseRequestOptionsFromJSON(requestOptionsJSON);
+      is(Object.getOwnPropertyNames(requestOptions).length, 4, "request options should have 4 properties");
+      arrayBufferEqualsArray(requestOptions.challenge, [ 223, 37, 182, 88, 112, 255, 141, 181 ], "challenge should be as expected");
+      is(requestOptions.timeout, undefined, "timeout should be undefined");
+      is(requestOptions.rpId, undefined, "rpId should be undefined");
+      isEmptyArray(requestOptions.allowCredentials, "allowCredentials should be an empty array");
+      is(requestOptions.userVerification, "preferred", "userVerification should be preferred");
+      is(Object.getOwnPropertyNames(requestOptions.extensions).length, 0, "extensions should be an empty object");
+    });
+
+    add_task(function test_parseRequestOptionsFromJSON() {
+      let requestOptionsJSON = {
+        challenge: "QAfaZwEQCkQ",
+        timeout: 25000,
+        rpId: "example.com",
+        allowCredentials: [{type: "public-key", id: "BTBXXGuXRTk", transports: ["smart-card"] }],
+        userVerification: "discouraged",
+        hints: ["client-device"],
+        attestation: "enterprise",
+        attestationFormats: ["packed"],
+        extensions: { appid: "https://www.example.com/anotherAppID", hmacCreateSecret: false },
+      };
+      let requestOptions = PublicKeyCredential.parseRequestOptionsFromJSON(requestOptionsJSON);
+      is(Object.getOwnPropertyNames(requestOptions).length, 6, "request options should have 6 properties");
+      arrayBufferEqualsArray(requestOptions.challenge, [ 64, 7, 218, 103, 1, 16, 10, 68 ], "challenge should be as expected");
+      is(requestOptions.timeout, 25000, "timeout should be 25000");
+      is(requestOptions.rpId, "example.com", "rpId should be example.com");
+      is(requestOptions.allowCredentials.length, 1, "allowCredentials should have one element");
+      is(requestOptions.allowCredentials[0].type, "public-key", "allowCredentials[0].type should be public-key");
+      arrayBufferEqualsArray(requestOptions.allowCredentials[0].id, [ 5, 48, 87, 92, 107, 151, 69, 57 ], "allowCredentials[0].id should be as expected");
+      is(requestOptions.allowCredentials[0].transports.length, 1, "allowCredentials[0].transports should have one element");
+      is(requestOptions.allowCredentials[0].transports[0], "smart-card", "allowCredentials[0].transports[0] should be usb");
+      is(requestOptions.userVerification, "discouraged", "userVerification should be discouraged");
+      is(requestOptions.extensions.appid, "https://www.example.com/anotherAppID", "extensions.appid should be https://www.example.com/anotherAppID");
+      is(requestOptions.extensions.hmacCreateSecret, false, "extensions.hmacCreateSecret should be false");
+    });
+
+    add_task(function test_parseRequestOptionsFromJSON_malformed() {
+      let challengeNotBase64 = {
+        challenge: "/not+urlsafe+base64/",
+      };
+      shouldThrow(
+        () => { PublicKeyCredential.parseRequestOptionsFromJSON(challengeNotBase64); },
+        "PublicKeyCredential.parseRequestOptionsFromJSON: could not decode challenge as urlsafe base64",
+        "should get encoding error if challenge is not urlsafe base64"
+      );
+
+      let allowCredentialsIdNotBase64 = {
+        challenge: "QAfaZwEQCkQ",
+        timeout: 25000,
+        rpId: "example.com",
+        allowCredentials: [{type: "public-key", id: "not urlsafe base64", transports: ["smart-card"] }],
+        userVerification: "discouraged",
+        hints: ["client-device"],
+        attestation: "enterprise",
+        attestationFormats: ["packed"],
+        extensions: { appid: "https://www.example.com/anotherAppID", hmacCreateSecret: false },
+      };
+      shouldThrow(
+        () => { PublicKeyCredential.parseRequestOptionsFromJSON(allowCredentialsIdNotBase64); },
+        "PublicKeyCredential.parseRequestOptionsFromJSON: could not decode allowed credential ID as urlsafe base64",
+        "should get encoding error if allowCredentials[0].id is not urlsafe base64"
+      );
+    });
+
+    add_task(async () => {
+      await addVirtualAuthenticator();
+    });
+
+    function isUrlsafeBase64(urlsafeBase64) {
+      try {
+        atob(urlsafeBase64.replace(/_/g, "/").replace(/-/g, "+"));
+        return true;
+      } catch (_) {}
+      return false;
+    }
+
+    add_task(async function test_registrationResponse_toJSON() {
+      let publicKey = {
+        rp: {id: document.domain, name: "none", icon: "none"},
+        user: {id: new Uint8Array(), name: "none", icon: "none", displayName: "none"},
+        challenge: crypto.getRandomValues(new Uint8Array(16)),
+        pubKeyCredParams: [{type: "public-key", alg: cose_alg_ECDSA_w_SHA256}],
+      };
+      let registrationResponse = await navigator.credentials.create({publicKey});
+      let registrationResponseJSON = registrationResponse.toJSON();
+      is(Object.keys(registrationResponseJSON).length, 5, "registrationResponseJSON should have 5 properties");
+      is(registrationResponseJSON.id, registrationResponseJSON.rawId, "registrationResponseJSON.id and rawId should be the same");
+      ok(isUrlsafeBase64(registrationResponseJSON.id), "registrationResponseJSON.id should be urlsafe base64");
+      is(Object.keys(registrationResponseJSON.response).length, 6, "registrationResponseJSON.response should have 6 properties");
+      ok(isUrlsafeBase64(registrationResponseJSON.response.clientDataJSON), "registrationResponseJSON.response.clientDataJSON should be urlsafe base64");
+      ok(isUrlsafeBase64(registrationResponseJSON.response.authenticatorData), "registrationResponseJSON.response.authenticatorData should be urlsafe base64");
+      ok(isUrlsafeBase64(registrationResponseJSON.response.publicKey), "registrationResponseJSON.response.publicKey should be urlsafe base64");
+      ok(isUrlsafeBase64(registrationResponseJSON.response.attestationObject), "registrationResponseJSON.response.attestationObject should be urlsafe base64");
+      is(registrationResponseJSON.response.publicKeyAlgorithm, cose_alg_ECDSA_w_SHA256, "registrationResponseJSON.response.publicKeyAlgorithm should be ECDSA with SHA256 (COSE)");
+      is(registrationResponseJSON.response.transports.length, 1, "registrationResponseJSON.response.transports.length should be 1");
+      is(registrationResponseJSON.response.transports[0], "usb", "registrationResponseJSON.response.transports[0] should be usb");
+      is(registrationResponseJSON.type, "public-key", "registrationResponseJSON.type should be public-key");
+    });
+
+    add_task(async function test_assertionResponse_toJSON() {
+      let registrationRequest = {
+        publicKey: {
+          rp: {id: document.domain, name: "none", icon: "none"},
+          user: {id: new Uint8Array(), name: "none", icon: "none", displayName: "none"},
+          challenge: crypto.getRandomValues(new Uint8Array(16)),
+          pubKeyCredParams: [{type: "public-key", alg: cose_alg_ECDSA_w_SHA256}],
+        },
+      };
+      let registrationResponse = await navigator.credentials.create(registrationRequest);
+
+      let assertionRequest = {
+        publicKey: {
+          challenge: crypto.getRandomValues(new Uint8Array(16)),
+          allowCredentials: [{ type: "public-key", id: registrationResponse.rawId }],
+        },
+      };
+      let assertionResponse = await navigator.credentials.get(assertionRequest);
+      let assertionResponseJSON = assertionResponse.toJSON();
+      is(Object.keys(assertionResponseJSON).length, 5, "assertionResponseJSON should have 5 properties");
+      is(assertionResponseJSON.id, assertionResponseJSON.rawId, "assertionResponseJSON.id and rawId should be the same");
+      ok(isUrlsafeBase64(assertionResponseJSON.id), "assertionResponseJSON.id should be urlsafe base64");
+      is(Object.keys(assertionResponseJSON.response).length, 3, "assertionResponseJSON.response should have 3 properties");
+      ok(isUrlsafeBase64(assertionResponseJSON.response.clientDataJSON), "assertionResponseJSON.response.clientDataJSON should be urlsafe base64");
+      ok(isUrlsafeBase64(assertionResponseJSON.response.authenticatorData), "assertionResponseJSON.response.authenticatorData should be urlsafe base64");
+      ok(isUrlsafeBase64(assertionResponseJSON.response.signature), "assertionResponseJSON.response.signature should be urlsafe base64");
+      is(Object.keys(assertionResponseJSON.clientExtensionResults).length, 0, "assertionResponseJSON.clientExtensionResults should be an empty dictionary");
+      is(assertionResponseJSON.type, "public-key", "assertionResponseJSON.type should be public-key");
+    });
+  </script>
+
+</body>
+</html>
diff --git a/dom/webidl/WebAuthentication.webidl b/dom/webidl/WebAuthentication.webidl
index f79c0760997f..9fc499da2e40 100644
--- a/dom/webidl/WebAuthentication.webidl
+++ b/dom/webidl/WebAuthentication.webidl
@@ -15,6 +15,66 @@ interface PublicKeyCredential : Credential {
     [SameObject, Throws] readonly attribute ArrayBuffer      rawId;
     [SameObject] readonly attribute AuthenticatorResponse    response;
     AuthenticationExtensionsClientOutputs getClientExtensionResults();
+    [Throws] object toJSON();
+};
+
+typedef DOMString Base64URLString;
+
+[GenerateConversionToJS]
+dictionary RegistrationResponseJSON {
+    required Base64URLString id;
+    required Base64URLString rawId;
+    required AuthenticatorAttestationResponseJSON response;
+    DOMString authenticatorAttachment;
+    required AuthenticationExtensionsClientOutputsJSON clientExtensionResults;
+    required DOMString type;
+};
+
+[GenerateConversionToJS]
+dictionary AuthenticatorAttestationResponseJSON {
+    required Base64URLString clientDataJSON;
+    required Base64URLString authenticatorData;
+    required sequence<DOMString> transports;
+    // The publicKey field will be missing if pubKeyCredParams was used to
+    // negotiate a public-key algorithm that the user agent doesn’t
+    // understand. (See section “Easily accessing credential data” for a
+    // list of which algorithms user agents must support.) If using such an
+    // algorithm then the public key must be parsed directly from
+    // attestationObject or authenticatorData.
+    Base64URLString publicKey;
+    required long long publicKeyAlgorithm;
+    // This value contains copies of some of the fields above. See
+    // section “Easily accessing credential data”.
+    required Base64URLString attestationObject;
+};
+
+[GenerateConversionToJS]
+dictionary AuthenticationResponseJSON {
+    required Base64URLString id;
+    required Base64URLString rawId;
+    required AuthenticatorAssertionResponseJSON response;
+    DOMString authenticatorAttachment;
+    required AuthenticationExtensionsClientOutputsJSON clientExtensionResults;
+    required DOMString type;
+};
+
+[GenerateConversionToJS]
+dictionary AuthenticatorAssertionResponseJSON {
+    required Base64URLString clientDataJSON;
+    required Base64URLString authenticatorData;
+    required Base64URLString signature;
+    Base64URLString userHandle;
+    Base64URLString attestationObject;
+};
+
+[GenerateConversionToJS]
+dictionary AuthenticationExtensionsClientOutputsJSON {
+    // FIDO AppID Extension (appid)
+    // <https://w3c.github.io/webauthn/#sctn-appid-extension>
+    boolean appid;
+
+    // <https://fidoalliance.org/specs/fido-v2.0-ps-20190130/fido-client-to-authenticator-protocol-v2.0-ps-20190130.html#sctn-hmac-secret-extension>
+    boolean hmacCreateSecret;
 };
 
 [SecureContext]
@@ -24,6 +84,64 @@ partial interface PublicKeyCredential {
     [NewObject] static Promise<boolean> isExternalCTAP2SecurityKeySupported();
 };
 
+[SecureContext]
+partial interface PublicKeyCredential {
+    [Throws] static PublicKeyCredentialCreationOptions parseCreationOptionsFromJSON(PublicKeyCredentialCreationOptionsJSON options);
+};
+
+dictionary PublicKeyCredentialCreationOptionsJSON {
+    required PublicKeyCredentialRpEntity                    rp;
+    required PublicKeyCredentialUserEntityJSON              user;
+    required Base64URLString                                challenge;
+    required sequence<PublicKeyCredentialParameters>        pubKeyCredParams;
+    unsigned long                                           timeout;
+    sequence<PublicKeyCredentialDescriptorJSON>             excludeCredentials = [];
+    AuthenticatorSelectionCriteria                          authenticatorSelection;
+    sequence<DOMString>                                     hints = [];
+    DOMString                                               attestation = "none";
+    sequence<DOMString>                                     attestationFormats = [];
+    AuthenticationExtensionsClientInputsJSON                extensions;
+};
+
+dictionary PublicKeyCredentialUserEntityJSON {
+    required Base64URLString        id;
+    required DOMString              name;
+    required DOMString              displayName;
+};
+
+dictionary PublicKeyCredentialDescriptorJSON {
+    required Base64URLString        id;
+    required DOMString              type;
+    sequence<DOMString>             transports;
+};
+
+dictionary AuthenticationExtensionsClientInputsJSON {
+    // FIDO AppID Extension (appid)
+    // <https://w3c.github.io/webauthn/#sctn-appid-extension>
+    USVString appid;
+
+    // hmac-secret
+    // <https://fidoalliance.org/specs/fido-v2.0-ps-20190130/fido-client-to-authenticator-protocol-v2.0-ps-20190130.html#sctn-hmac-secret-extension>
+    boolean hmacCreateSecret;
+};
+
+[SecureContext]
+partial interface PublicKeyCredential {
+    [Throws] static PublicKeyCredentialRequestOptions parseRequestOptionsFromJSON(PublicKeyCredentialRequestOptionsJSON options);
+};
+
+dictionary PublicKeyCredentialRequestOptionsJSON {
+    required Base64URLString                                challenge;
+    unsigned long                                           timeout;
+    DOMString                                               rpId;
+    sequence<PublicKeyCredentialDescriptorJSON>             allowCredentials = [];
+    DOMString                                               userVerification = "preferred";
+    sequence<DOMString>                                     hints = [];
+    DOMString                                               attestation = "none";
+    sequence<DOMString>                                     attestationFormats = [];
+    AuthenticationExtensionsClientInputsJSON                extensions;
+};
+
 [SecureContext, Pref="security.webauth.webauthn",
  Exposed=Window]
 interface AuthenticatorResponse {