diff --git a/api/crypto/frame_decryptor_interface.h b/api/crypto/frame_decryptor_interface.h
index 69f1375..ec900ab 100644
--- a/api/crypto/frame_decryptor_interface.h
+++ b/api/crypto/frame_decryptor_interface.h
@@ -34,8 +34,9 @@
   // returned when attempting to decrypt a frame. kRecoverable indicates that
   // there was an error with the given frame and so it should not be passed to
   // the decoder, however it hints that the receive stream is still decryptable
-  // which is important for determining when to send key frame requests.
-  enum class Status { kOk, kRecoverable, kFailedToDecrypt };
+  // which is important for determining when to send key frame requests
+  // kUnknown should never be returned by the implementor.
+  enum class Status { kOk, kRecoverable, kFailedToDecrypt, kUnknown };
 
   struct Result {
     Result(Status status, size_t bytes_written)
@@ -54,33 +55,15 @@
   // that the frames are in order if SRTP is enabled. The stream is not provided
   // here and it is up to the implementor to transport this information to the
   // receiver if they care about it. You must set bytes_written to how many
-  // bytes you wrote to in the frame buffer. 0 must be returned if successful
-  // all other numbers can be selected by the implementer to represent error
-  // codes.
-  // TODO(bugs.webrtc.org/10512) - Remove this after implementation rewrite.
-  virtual int Decrypt(cricket::MediaType media_type,
-                      const std::vector<uint32_t>& csrcs,
-                      rtc::ArrayView<const uint8_t> additional_data,
-                      rtc::ArrayView<const uint8_t> encrypted_frame,
-                      rtc::ArrayView<uint8_t> frame,
-                      size_t* bytes_written) {
-    bytes_written = 0;
-    return 1;
-  }
-
-  // TODO(bugs.webrtc.org/10512) - Remove the other decrypt function and turn
-  // this to a pure virtual.
+  // bytes you wrote to in the frame buffer. kOk must be returned if successful,
+  // kRecoverable should be returned if the failure was due to something other
+  // than a decryption failure. kFailedToDecrypt should be returned in all other
+  // cases.
   virtual Result Decrypt(cricket::MediaType media_type,
                          const std::vector<uint32_t>& csrcs,
                          rtc::ArrayView<const uint8_t> additional_data,
                          rtc::ArrayView<const uint8_t> encrypted_frame,
-                         rtc::ArrayView<uint8_t> frame) {
-    size_t bytes_written = 0;
-    const int status = Decrypt(media_type, csrcs, additional_data,
-                               encrypted_frame, frame, &bytes_written);
-    return Result(status == 0 ? Status::kOk : Status::kFailedToDecrypt,
-                  bytes_written);
-  }
+                         rtc::ArrayView<uint8_t> frame) = 0;
 
   // Returns the total required length in bytes for the output of the
   // decryption. This can be larger than the actual number of bytes you need but
diff --git a/api/test/fake_frame_decryptor.cc b/api/test/fake_frame_decryptor.cc
index b77017f..4af42a6 100644
--- a/api/test/fake_frame_decryptor.cc
+++ b/api/test/fake_frame_decryptor.cc
@@ -18,14 +18,14 @@
                                        uint8_t expected_postfix_byte)
     : fake_key_(fake_key), expected_postfix_byte_(expected_postfix_byte) {}
 
-int FakeFrameDecryptor::Decrypt(cricket::MediaType media_type,
-                                const std::vector<uint32_t>& csrcs,
-                                rtc::ArrayView<const uint8_t> additional_data,
-                                rtc::ArrayView<const uint8_t> encrypted_frame,
-                                rtc::ArrayView<uint8_t> frame,
-                                size_t* bytes_written) {
+FakeFrameDecryptor::Result FakeFrameDecryptor::Decrypt(
+    cricket::MediaType media_type,
+    const std::vector<uint32_t>& csrcs,
+    rtc::ArrayView<const uint8_t> additional_data,
+    rtc::ArrayView<const uint8_t> encrypted_frame,
+    rtc::ArrayView<uint8_t> frame) {
   if (fail_decryption_) {
-    return static_cast<int>(FakeDecryptStatus::FORCED_FAILURE);
+    return Result(Status::kFailedToDecrypt, 0);
   }
 
   RTC_CHECK_EQ(frame.size() + 1, encrypted_frame.size());
@@ -34,11 +34,10 @@
   }
 
   if (encrypted_frame[frame.size()] != expected_postfix_byte_) {
-    return static_cast<int>(FakeDecryptStatus::INVALID_POSTFIX);
+    return Result(Status::kFailedToDecrypt, 0);
   }
 
-  *bytes_written = frame.size();
-  return static_cast<int>(FakeDecryptStatus::OK);
+  return Result(Status::kOk, frame.size());
 }
 
 size_t FakeFrameDecryptor::GetMaxPlaintextByteSize(
diff --git a/api/test/fake_frame_decryptor.h b/api/test/fake_frame_decryptor.h
index cb370b9..05813db 100644
--- a/api/test/fake_frame_decryptor.h
+++ b/api/test/fake_frame_decryptor.h
@@ -35,12 +35,11 @@
                               uint8_t expected_postfix_byte = 255);
   // Fake decryption that just xors the payload with the 1 byte key and checks
   // the postfix byte. This will always fail if fail_decryption_ is set to true.
-  int Decrypt(cricket::MediaType media_type,
-              const std::vector<uint32_t>& csrcs,
-              rtc::ArrayView<const uint8_t> additional_data,
-              rtc::ArrayView<const uint8_t> encrypted_frame,
-              rtc::ArrayView<uint8_t> frame,
-              size_t* bytes_written) override;
+  Result Decrypt(cricket::MediaType media_type,
+                 const std::vector<uint32_t>& csrcs,
+                 rtc::ArrayView<const uint8_t> additional_data,
+                 rtc::ArrayView<const uint8_t> encrypted_frame,
+                 rtc::ArrayView<uint8_t> frame) override;
   // Always returns 1 less than the size of the encrypted frame.
   size_t GetMaxPlaintextByteSize(cricket::MediaType media_type,
                                  size_t encrypted_frame_size) override;
diff --git a/api/test/mock_frame_decryptor.h b/api/test/mock_frame_decryptor.h
index feac9b3..77aa4f9 100644
--- a/api/test/mock_frame_decryptor.h
+++ b/api/test/mock_frame_decryptor.h
@@ -23,13 +23,12 @@
   MockFrameDecryptor();
   ~MockFrameDecryptor() override;
 
-  MOCK_METHOD6(Decrypt,
-               int(cricket::MediaType,
-                   const std::vector<uint32_t>&,
-                   rtc::ArrayView<const uint8_t>,
-                   rtc::ArrayView<const uint8_t>,
-                   rtc::ArrayView<uint8_t>,
-                   size_t*));
+  MOCK_METHOD5(Decrypt,
+               Result(cricket::MediaType,
+                      const std::vector<uint32_t>&,
+                      rtc::ArrayView<const uint8_t>,
+                      rtc::ArrayView<const uint8_t>,
+                      rtc::ArrayView<uint8_t>));
 
   MOCK_METHOD2(GetMaxPlaintextByteSize,
                size_t(cricket::MediaType, size_t encrypted_frame_size));
diff --git a/audio/channel_receive.cc b/audio/channel_receive.cc
index 088aa57..4f00d9f 100644
--- a/audio/channel_receive.cc
+++ b/audio/channel_receive.cc
@@ -103,8 +103,8 @@
   void StopPlayout() override;
 
   // Codecs
-  absl::optional<std::pair<int, SdpAudioFormat>>
-      GetReceiveCodec() const override;
+  absl::optional<std::pair<int, SdpAudioFormat>> GetReceiveCodec()
+      const override;
 
   void ReceivedRTCPPacket(const uint8_t* data, size_t length) override;
 
@@ -627,28 +627,26 @@
   // Keep this buffer around for the lifetime of the OnReceivedPayloadData call.
   rtc::Buffer decrypted_audio_payload;
   if (frame_decryptor_ != nullptr) {
-    size_t max_plaintext_size = frame_decryptor_->GetMaxPlaintextByteSize(
+    const size_t max_plaintext_size = frame_decryptor_->GetMaxPlaintextByteSize(
         cricket::MEDIA_TYPE_AUDIO, payload_length);
     decrypted_audio_payload.SetSize(max_plaintext_size);
 
-    size_t bytes_written = 0;
-    std::vector<uint32_t> csrcs(header.arrOfCSRCs,
-                                header.arrOfCSRCs + header.numCSRCs);
-    int decrypt_status = frame_decryptor_->Decrypt(
-        cricket::MEDIA_TYPE_AUDIO, csrcs,
-        /*additional_data=*/nullptr,
-        rtc::ArrayView<const uint8_t>(payload, payload_data_length),
-        decrypted_audio_payload, &bytes_written);
+    const std::vector<uint32_t> csrcs(header.arrOfCSRCs,
+                                      header.arrOfCSRCs + header.numCSRCs);
+    const FrameDecryptorInterface::Result decrypt_result =
+        frame_decryptor_->Decrypt(
+            cricket::MEDIA_TYPE_AUDIO, csrcs,
+            /*additional_data=*/nullptr,
+            rtc::ArrayView<const uint8_t>(payload, payload_data_length),
+            decrypted_audio_payload);
 
-    // In this case just interpret the failure as a silent frame.
-    if (decrypt_status != 0) {
-      bytes_written = 0;
+    if (decrypt_result.IsOk()) {
+      decrypted_audio_payload.SetSize(decrypt_result.bytes_written);
+    } else {
+      // Interpret failures as a silent frame.
+      decrypted_audio_payload.SetSize(0);
     }
 
-    // Resize the decrypted audio payload to the number of bytes actually
-    // written.
-    decrypted_audio_payload.SetSize(bytes_written);
-    // Update the final payload.
     payload = decrypted_audio_payload.data();
     payload_data_length = decrypted_audio_payload.size();
   } else if (crypto_options_.sframe.require_frame_encryption) {
diff --git a/video/buffered_frame_decryptor.cc b/video/buffered_frame_decryptor.cc
index 2d7ec25..41eddea 100644
--- a/video/buffered_frame_decryptor.cc
+++ b/video/buffered_frame_decryptor.cc
@@ -83,25 +83,25 @@
   }
 
   // Attempt to decrypt the video frame.
-  size_t bytes_written = 0;
-  const int status = frame_decryptor_->Decrypt(
-      cricket::MEDIA_TYPE_VIDEO, /*csrcs=*/{}, additional_data, *frame,
-      inline_decrypted_bitstream, &bytes_written);
-
+  const FrameDecryptorInterface::Result decrypt_result =
+      frame_decryptor_->Decrypt(cricket::MEDIA_TYPE_VIDEO, /*csrcs=*/{},
+                                additional_data, *frame,
+                                inline_decrypted_bitstream);
   // Optionally call the callback if there was a change in status
-  if (status != last_status_) {
-    last_status_ = status;
-    decryption_status_change_callback_->OnDecryptionStatusChange(status);
+  if (decrypt_result.status != last_status_) {
+    last_status_ = decrypt_result.status;
+    decryption_status_change_callback_->OnDecryptionStatusChange(
+        decrypt_result.status);
   }
 
-  if (status != 0) {
+  if (!decrypt_result.IsOk()) {
     // Only stash frames if we have never decrypted a frame before.
     return first_frame_decrypted_ ? FrameDecision::kDrop
                                   : FrameDecision::kStash;
   }
-  RTC_CHECK_LE(bytes_written, max_plaintext_byte_size);
+  RTC_CHECK_LE(decrypt_result.bytes_written, max_plaintext_byte_size);
   // Update the frame to contain just the written bytes.
-  frame->set_size(bytes_written);
+  frame->set_size(decrypt_result.bytes_written);
 
   // Indicate that all future fail to decrypt frames should be dropped.
   if (!first_frame_decrypted_) {
diff --git a/video/buffered_frame_decryptor.h b/video/buffered_frame_decryptor.h
index 06992bb..49ab9a7 100644
--- a/video/buffered_frame_decryptor.h
+++ b/video/buffered_frame_decryptor.h
@@ -42,7 +42,8 @@
   // blocking so the caller must relinquish the callback quickly. This status
   // must match what is specified in the FrameDecryptorInterface file. Notably
   // 0 must indicate success and any positive integer is a failure.
-  virtual void OnDecryptionStatusChange(int status) = 0;
+  virtual void OnDecryptionStatusChange(
+      FrameDecryptorInterface::Status status) = 0;
 };
 
 // The BufferedFrameDecryptor is responsible for deciding when to pass
@@ -91,7 +92,8 @@
 
   const bool generic_descriptor_auth_experiment_;
   bool first_frame_decrypted_ = false;
-  int last_status_ = -1;
+  FrameDecryptorInterface::Status last_status_ =
+      FrameDecryptorInterface::Status::kUnknown;
   rtc::scoped_refptr<FrameDecryptorInterface> frame_decryptor_;
   OnDecryptedFrameCallback* const decrypted_frame_callback_;
   OnDecryptionStatusChangeCallback* const decryption_status_change_callback_;
diff --git a/video/buffered_frame_decryptor_unittest.cc b/video/buffered_frame_decryptor_unittest.cc
index 7926f24..a056b4a 100644
--- a/video/buffered_frame_decryptor_unittest.cc
+++ b/video/buffered_frame_decryptor_unittest.cc
@@ -55,6 +55,16 @@
   std::map<uint16_t, VCMPacket> packets_;
 };
 
+FrameDecryptorInterface::Result DecryptSuccess() {
+  return FrameDecryptorInterface::Result(FrameDecryptorInterface::Status::kOk,
+                                         0);
+}
+
+FrameDecryptorInterface::Result DecryptFail() {
+  return FrameDecryptorInterface::Result(
+      FrameDecryptorInterface::Status::kFailedToDecrypt, 0);
+}
+
 }  // namespace
 
 class BufferedFrameDecryptorTest
@@ -69,7 +79,7 @@
     decrypted_frame_call_count_++;
   }
 
-  void OnDecryptionStatusChange(int status) {
+  void OnDecryptionStatusChange(FrameDecryptorInterface::Status status) {
     ++decryption_status_change_count_;
   }
 
@@ -127,7 +137,9 @@
 
 // Callback should always be triggered on a successful decryption.
 TEST_F(BufferedFrameDecryptorTest, CallbackCalledOnSuccessfulDecryption) {
-  EXPECT_CALL(*mock_frame_decryptor_, Decrypt).Times(1).WillOnce(Return(0));
+  EXPECT_CALL(*mock_frame_decryptor_, Decrypt)
+      .Times(1)
+      .WillOnce(Return(DecryptSuccess()));
   EXPECT_CALL(*mock_frame_decryptor_, GetMaxPlaintextByteSize)
       .Times(1)
       .WillOnce(Return(0));
@@ -138,7 +150,9 @@
 
 // An initial fail to decrypt should not trigger the callback.
 TEST_F(BufferedFrameDecryptorTest, CallbackNotCalledOnFailedDecryption) {
-  EXPECT_CALL(*mock_frame_decryptor_, Decrypt).Times(1).WillOnce(Return(1));
+  EXPECT_CALL(*mock_frame_decryptor_, Decrypt)
+      .Times(1)
+      .WillOnce(Return(DecryptFail()));
   EXPECT_CALL(*mock_frame_decryptor_, GetMaxPlaintextByteSize)
       .Times(1)
       .WillOnce(Return(0));
@@ -152,9 +166,9 @@
 TEST_F(BufferedFrameDecryptorTest, DelayedCallbackOnBufferedFrames) {
   EXPECT_CALL(*mock_frame_decryptor_, Decrypt)
       .Times(3)
-      .WillOnce(Return(1))
-      .WillOnce(Return(0))
-      .WillOnce(Return(0));
+      .WillOnce(Return(DecryptFail()))
+      .WillOnce(Return(DecryptSuccess()))
+      .WillOnce(Return(DecryptSuccess()));
   EXPECT_CALL(*mock_frame_decryptor_, GetMaxPlaintextByteSize)
       .Times(3)
       .WillRepeatedly(Return(0));
@@ -174,10 +188,10 @@
 TEST_F(BufferedFrameDecryptorTest, FTDDiscardedAfterFirstSuccess) {
   EXPECT_CALL(*mock_frame_decryptor_, Decrypt)
       .Times(4)
-      .WillOnce(Return(1))
-      .WillOnce(Return(0))
-      .WillOnce(Return(0))
-      .WillOnce(Return(1));
+      .WillOnce(Return(DecryptFail()))
+      .WillOnce(Return(DecryptSuccess()))
+      .WillOnce(Return(DecryptSuccess()))
+      .WillOnce(Return(DecryptFail()));
   EXPECT_CALL(*mock_frame_decryptor_, GetMaxPlaintextByteSize)
       .Times(4)
       .WillRepeatedly(Return(0));
@@ -203,7 +217,7 @@
   const size_t failed_to_decrypt_count = kMaxStashedFrames * 2;
   EXPECT_CALL(*mock_frame_decryptor_, Decrypt)
       .Times(failed_to_decrypt_count)
-      .WillRepeatedly(Return(1));
+      .WillRepeatedly(Return(DecryptFail()));
   EXPECT_CALL(*mock_frame_decryptor_, GetMaxPlaintextByteSize)
       .WillRepeatedly(Return(0));
 
@@ -215,7 +229,7 @@
 
   EXPECT_CALL(*mock_frame_decryptor_, Decrypt)
       .Times(kMaxStashedFrames + 1)
-      .WillRepeatedly(Return(0));
+      .WillRepeatedly(Return(DecryptSuccess()));
   buffered_frame_decryptor_->ManageEncryptedFrame(CreateRtpFrameObject(true));
   EXPECT_EQ(decrypted_frame_call_count_, kMaxStashedFrames + 1);
   EXPECT_EQ(decryption_status_change_count_, static_cast<size_t>(2));
@@ -231,7 +245,7 @@
 
   EXPECT_CALL(*mock_frame_decryptor_, Decrypt)
       .Times(kMaxStashedFrames + 1)
-      .WillRepeatedly(Return(0));
+      .WillRepeatedly(Return(DecryptSuccess()));
   EXPECT_CALL(*mock_frame_decryptor_, GetMaxPlaintextByteSize)
       .WillRepeatedly(Return(0));
 
diff --git a/video/rtp_video_stream_receiver.cc b/video/rtp_video_stream_receiver.cc
index 87b735c..2381bef 100644
--- a/video/rtp_video_stream_receiver.cc
+++ b/video/rtp_video_stream_receiver.cc
@@ -451,8 +451,11 @@
   reference_finder_->ManageFrame(std::move(frame));
 }
 
-void RtpVideoStreamReceiver::OnDecryptionStatusChange(int status) {
-  frames_decryptable_.store(status == 0);
+void RtpVideoStreamReceiver::OnDecryptionStatusChange(
+    FrameDecryptorInterface::Status status) {
+  frames_decryptable_.store(
+      (status == FrameDecryptorInterface::Status::kOk) ||
+      (status == FrameDecryptorInterface::Status::kRecoverable));
 }
 
 void RtpVideoStreamReceiver::SetFrameDecryptor(
diff --git a/video/rtp_video_stream_receiver.h b/video/rtp_video_stream_receiver.h
index 7caeedc..14f5f4d 100644
--- a/video/rtp_video_stream_receiver.h
+++ b/video/rtp_video_stream_receiver.h
@@ -153,7 +153,8 @@
       std::unique_ptr<video_coding::RtpFrameObject> frame) override;
 
   // Implements OnDecryptionStatusChangeCallback.
-  void OnDecryptionStatusChange(int status) override;
+  void OnDecryptionStatusChange(
+      FrameDecryptorInterface::Status status) override;
 
   // Optionally set a frame decryptor after a stream has started. This will not
   // reset the decoder state.