diff --git a/cas/1.1/default/DescramblerImpl.cpp b/cas/1.1/default/DescramblerImpl.cpp
new file mode 100644
index 0000000..36dc1a5
--- /dev/null
+++ b/cas/1.1/default/DescramblerImpl.cpp
@@ -0,0 +1,195 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+//#define LOG_NDEBUG 0
+#define LOG_TAG "android.hardware.cas@1.1-DescramblerImpl"
+
+#include <hidlmemory/mapping.h>
+#include <media/cas/DescramblerAPI.h>
+#include <media/hardware/CryptoAPI.h>
+#include <media/stagefright/foundation/AUtils.h>
+#include <utils/Log.h>
+
+#include "DescramblerImpl.h"
+#include "SharedLibrary.h"
+#include "TypeConvert.h"
+
+namespace android {
+using hidl::memory::V1_0::IMemory;
+
+namespace hardware {
+namespace cas {
+namespace V1_1 {
+namespace implementation {
+
+#define CHECK_SUBSAMPLE_DEF(type)                                                                 \
+    static_assert(sizeof(SubSample) == sizeof(type::SubSample), "SubSample: size doesn't match"); \
+    static_assert(offsetof(SubSample, numBytesOfClearData) ==                                     \
+                          offsetof(type::SubSample, mNumBytesOfClearData),                        \
+                  "SubSample: numBytesOfClearData offset doesn't match");                         \
+    static_assert(offsetof(SubSample, numBytesOfEncryptedData) ==                                 \
+                          offsetof(type::SubSample, mNumBytesOfEncryptedData),                    \
+                  "SubSample: numBytesOfEncryptedData offset doesn't match")
+
+CHECK_SUBSAMPLE_DEF(DescramblerPlugin);
+CHECK_SUBSAMPLE_DEF(CryptoPlugin);
+
+DescramblerImpl::DescramblerImpl(const sp<SharedLibrary>& library, DescramblerPlugin* plugin)
+    : mLibrary(library), mPluginHolder(plugin) {
+    ALOGV("CTOR: plugin=%p", mPluginHolder.get());
+}
+
+DescramblerImpl::~DescramblerImpl() {
+    ALOGV("DTOR: plugin=%p", mPluginHolder.get());
+    release();
+}
+
+Return<Status> DescramblerImpl::setMediaCasSession(const HidlCasSessionId& sessionId) {
+    ALOGV("%s: sessionId=%s", __FUNCTION__, sessionIdToString(sessionId).string());
+
+    std::shared_ptr<DescramblerPlugin> holder = std::atomic_load(&mPluginHolder);
+    if (holder.get() == nullptr) {
+        return toStatus(INVALID_OPERATION);
+    }
+
+    return toStatus(holder->setMediaCasSession(sessionId));
+}
+
+Return<bool> DescramblerImpl::requiresSecureDecoderComponent(const hidl_string& mime) {
+    std::shared_ptr<DescramblerPlugin> holder = std::atomic_load(&mPluginHolder);
+    if (holder.get() == nullptr) {
+        return false;
+    }
+
+    return holder->requiresSecureDecoderComponent(String8(mime.c_str()));
+}
+
+static inline bool validateRangeForSize(uint64_t offset, uint64_t length, uint64_t size) {
+    return isInRange<uint64_t, uint64_t>(0, size, offset, length);
+}
+
+Return<void> DescramblerImpl::descramble(ScramblingControl scramblingControl,
+                                         const hidl_vec<SubSample>& subSamples,
+                                         const SharedBuffer& srcBuffer, uint64_t srcOffset,
+                                         const DestinationBuffer& dstBuffer, uint64_t dstOffset,
+                                         descramble_cb _hidl_cb) {
+    ALOGV("%s", __FUNCTION__);
+
+    // hidl_memory's size is stored in uint64_t, but mapMemory's mmap will map
+    // size in size_t. If size is over SIZE_MAX, mapMemory mapMemory could succeed
+    // but the mapped memory's actual size will be smaller than the reported size.
+    if (srcBuffer.heapBase.size() > SIZE_MAX) {
+        ALOGE("Invalid hidl_memory size: %llu", srcBuffer.heapBase.size());
+        android_errorWriteLog(0x534e4554, "79376389");
+        _hidl_cb(toStatus(BAD_VALUE), 0, NULL);
+        return Void();
+    }
+
+    sp<IMemory> srcMem = mapMemory(srcBuffer.heapBase);
+
+    // Validate if the offset and size in the SharedBuffer is consistent with the
+    // mapped ashmem, since the offset and size is controlled by client.
+    if (srcMem == NULL) {
+        ALOGE("Failed to map src buffer.");
+        _hidl_cb(toStatus(BAD_VALUE), 0, NULL);
+        return Void();
+    }
+    if (!validateRangeForSize(srcBuffer.offset, srcBuffer.size, (uint64_t)srcMem->getSize())) {
+        ALOGE("Invalid src buffer range: offset %llu, size %llu, srcMem size %llu",
+              srcBuffer.offset, srcBuffer.size, (uint64_t)srcMem->getSize());
+        android_errorWriteLog(0x534e4554, "67962232");
+        _hidl_cb(toStatus(BAD_VALUE), 0, NULL);
+        return Void();
+    }
+
+    // use 64-bit here to catch bad subsample size that might be overflowing.
+    uint64_t totalBytesInSubSamples = 0;
+    for (size_t i = 0; i < subSamples.size(); i++) {
+        totalBytesInSubSamples +=
+                (uint64_t)subSamples[i].numBytesOfClearData + subSamples[i].numBytesOfEncryptedData;
+    }
+    // Further validate if the specified srcOffset and requested total subsample size
+    // is consistent with the source shared buffer size.
+    if (!validateRangeForSize(srcOffset, totalBytesInSubSamples, srcBuffer.size)) {
+        ALOGE("Invalid srcOffset and subsample size: "
+              "srcOffset %llu, totalBytesInSubSamples %llu, srcBuffer size %llu",
+              srcOffset, totalBytesInSubSamples, srcBuffer.size);
+        android_errorWriteLog(0x534e4554, "67962232");
+        _hidl_cb(toStatus(BAD_VALUE), 0, NULL);
+        return Void();
+    }
+
+    void* srcPtr = (uint8_t*)(void*)srcMem->getPointer() + srcBuffer.offset;
+    void* dstPtr = NULL;
+    if (dstBuffer.type == BufferType::SHARED_MEMORY) {
+        // When using shared memory, src buffer is also used as dst,
+        // we don't map it again here.
+        dstPtr = srcPtr;
+
+        // In this case the dst and src would be the same buffer, need to validate
+        // dstOffset against the buffer size too.
+        if (!validateRangeForSize(dstOffset, totalBytesInSubSamples, srcBuffer.size)) {
+            ALOGE("Invalid dstOffset and subsample size: "
+                  "dstOffset %llu, totalBytesInSubSamples %llu, srcBuffer size %llu",
+                  dstOffset, totalBytesInSubSamples, srcBuffer.size);
+            android_errorWriteLog(0x534e4554, "67962232");
+            _hidl_cb(toStatus(BAD_VALUE), 0, NULL);
+            return Void();
+        }
+    } else {
+        native_handle_t* handle =
+                const_cast<native_handle_t*>(dstBuffer.secureMemory.getNativeHandle());
+        dstPtr = static_cast<void*>(handle);
+    }
+
+    // Get a local copy of the shared_ptr for the plugin. Note that before
+    // calling the HIDL callback, this shared_ptr must be manually reset,
+    // since the client side could proceed as soon as the callback is called
+    // without waiting for this method to go out of scope.
+    std::shared_ptr<DescramblerPlugin> holder = std::atomic_load(&mPluginHolder);
+    if (holder.get() == nullptr) {
+        _hidl_cb(toStatus(INVALID_OPERATION), 0, NULL);
+        return Void();
+    }
+
+    // Casting hidl SubSample to DescramblerPlugin::SubSample, but need
+    // to ensure structs are actually idential
+
+    int32_t result =
+            holder->descramble(dstBuffer.type != BufferType::SHARED_MEMORY,
+                               (DescramblerPlugin::ScramblingControl)scramblingControl,
+                               subSamples.size(), (DescramblerPlugin::SubSample*)subSamples.data(),
+                               srcPtr, srcOffset, dstPtr, dstOffset, NULL);
+
+    holder.reset();
+    _hidl_cb(toStatus(result >= 0 ? OK : result), result, NULL);
+    return Void();
+}
+
+Return<Status> DescramblerImpl::release() {
+    ALOGV("%s: plugin=%p", __FUNCTION__, mPluginHolder.get());
+
+    std::shared_ptr<DescramblerPlugin> holder(nullptr);
+    std::atomic_store(&mPluginHolder, holder);
+
+    return Status::OK;
+}
+
+}  // namespace implementation
+}  // namespace V1_1
+}  // namespace cas
+}  // namespace hardware
+}  // namespace android