diff --git a/drm/libmediadrm/CryptoHal.cpp b/drm/libmediadrm/CryptoHal.cpp
index 9f41403..25c16da 100644
--- a/drm/libmediadrm/CryptoHal.cpp
+++ b/drm/libmediadrm/CryptoHal.cpp
@@ -105,7 +105,8 @@
 CryptoHal::CryptoHal()
     : mFactories(makeCryptoFactories()),
       mInitCheck((mFactories.size() == 0) ? ERROR_UNSUPPORTED : NO_INIT),
-      mNextBufferId(0) {
+      mNextBufferId(0),
+      mHeapSeqNum(0) {
 }
 
 CryptoHal::~CryptoHal() {
@@ -225,30 +226,37 @@
  * size.  Once the heap base is established, shared memory buffers
  * are sent by providing an offset into the heap and a buffer size.
  */
-void CryptoHal::setHeapBase(const sp<IMemoryHeap>& heap) {
+int32_t CryptoHal::setHeapBase(const sp<IMemoryHeap>& heap) {
+    if (heap == NULL) {
+        ALOGE("setHeapBase(): heap is NULL");
+        return -1;
+    }
     native_handle_t* nativeHandle = native_handle_create(1, 0);
     if (!nativeHandle) {
         ALOGE("setHeapBase(), failed to create native handle");
-        return;
+        return -1;
     }
-    if (heap == NULL) {
-        ALOGE("setHeapBase(): heap is NULL");
-        return;
-    }
+
+    Mutex::Autolock autoLock(mLock);
+
+    int32_t seqNum = mHeapSeqNum++;
     int fd = heap->getHeapID();
     nativeHandle->data[0] = fd;
     auto hidlHandle = hidl_handle(nativeHandle);
     auto hidlMemory = hidl_memory("ashmem", hidlHandle, heap->getSize());
-    mHeapBases.add(heap->getBase(), mNextBufferId);
+    mHeapBases.add(seqNum, mNextBufferId);
     Return<void> hResult = mPlugin->setSharedBufferBase(hidlMemory, mNextBufferId++);
     ALOGE_IF(!hResult.isOk(), "setSharedBufferBase(): remote call failed");
+    return seqNum;
 }
 
-void CryptoHal::clearHeapBase(const sp<IMemoryHeap>& heap) {
-    mHeapBases.removeItem(heap->getBase());
+void CryptoHal::clearHeapBase(int32_t seqNum) {
+    Mutex::Autolock autoLock(mLock);
+
+    mHeapBases.removeItem(seqNum);
 }
 
-status_t CryptoHal::toSharedBuffer(const sp<IMemory>& memory, ::SharedBuffer* buffer) {
+status_t CryptoHal::toSharedBuffer(const sp<IMemory>& memory, int32_t seqNum, ::SharedBuffer* buffer) {
     ssize_t offset;
     size_t size;
 
@@ -262,9 +270,9 @@
     }
 
     // memory must be in the declared heap
-    CHECK(mHeapBases.indexOfKey(heap->getBase()) >= 0);
+    CHECK(mHeapBases.indexOfKey(seqNum) >= 0);
 
-    buffer->bufferId = mHeapBases.valueFor(heap->getBase());
+    buffer->bufferId = mHeapBases.valueFor(seqNum);
     buffer->offset = offset >= 0 ? offset : 0;
     buffer->size = size;
     return OK;
@@ -272,7 +280,7 @@
 
 ssize_t CryptoHal::decrypt(const uint8_t keyId[16], const uint8_t iv[16],
         CryptoPlugin::Mode mode, const CryptoPlugin::Pattern &pattern,
-        const sp<IMemory> &source, size_t offset,
+        const ICrypto::SourceBuffer &source, size_t offset,
         const CryptoPlugin::SubSample *subSamples, size_t numSubSamples,
         const ICrypto::DestinationBuffer &destination, AString *errorDetailMsg) {
     Mutex::Autolock autoLock(mLock);
@@ -312,11 +320,12 @@
     }
     auto hSubSamples = hidl_vec<SubSample>(stdSubSamples);
 
+    int32_t heapSeqNum = source.mHeapSeqNum;
     bool secure;
     ::DestinationBuffer hDestination;
     if (destination.mType == kDestinationTypeSharedMemory) {
         hDestination.type = BufferType::SHARED_MEMORY;
-        status_t status = toSharedBuffer(destination.mSharedMemory,
+        status_t status = toSharedBuffer(destination.mSharedMemory, heapSeqNum,
                 &hDestination.nonsecureMemory);
         if (status != OK) {
             return status;
@@ -329,7 +338,7 @@
     }
 
     ::SharedBuffer hSource;
-    status_t status = toSharedBuffer(source, &hSource);
+    status_t status = toSharedBuffer(source.mSharedMemory, heapSeqNum, &hSource);
     if (status != OK) {
         return status;
     }
diff --git a/drm/libmediadrm/ICrypto.cpp b/drm/libmediadrm/ICrypto.cpp
index 7b70205..8506d95 100644
--- a/drm/libmediadrm/ICrypto.cpp
+++ b/drm/libmediadrm/ICrypto.cpp
@@ -98,7 +98,7 @@
 
     virtual ssize_t decrypt(const uint8_t key[16], const uint8_t iv[16],
             CryptoPlugin::Mode mode, const CryptoPlugin::Pattern &pattern,
-            const sp<IMemory> &source, size_t offset,
+            const SourceBuffer &source, size_t offset,
             const CryptoPlugin::SubSample *subSamples, size_t numSubSamples,
             const DestinationBuffer &destination, AString *errorDetailMsg) {
         Parcel data, reply;
@@ -127,7 +127,8 @@
         }
 
         data.writeInt32(totalSize);
-        data.writeStrongBinder(IInterface::asBinder(source));
+        data.writeStrongBinder(IInterface::asBinder(source.mSharedMemory));
+        data.writeInt32(source.mHeapSeqNum);
         data.writeInt32(offset);
 
         data.writeInt32(numSubSamples);
@@ -179,18 +180,25 @@
         return reply.readInt32();
     }
 
-    virtual void setHeap(const sp<IMemoryHeap> &heap) {
+    virtual int32_t setHeap(const sp<IMemoryHeap> &heap) {
         Parcel data, reply;
         data.writeInterfaceToken(ICrypto::getInterfaceDescriptor());
         data.writeStrongBinder(IInterface::asBinder(heap));
-        remote()->transact(SET_HEAP, data, &reply);
-        return;
+        status_t err = remote()->transact(SET_HEAP, data, &reply);
+        if (err != NO_ERROR) {
+            return -1;
+        }
+        int32_t seqNum;
+        if (reply.readInt32(&seqNum) != NO_ERROR) {
+            return -1;
+        }
+        return seqNum;
     }
 
-    virtual void unsetHeap(const sp<IMemoryHeap>& heap) {
+    virtual void unsetHeap(int32_t seqNum) {
         Parcel data, reply;
         data.writeInterfaceToken(ICrypto::getInterfaceDescriptor());
-        data.writeStrongBinder(IInterface::asBinder(heap));
+        data.writeInt32(seqNum);
         remote()->transact(UNSET_HEAP, data, &reply);
         return;
     }
@@ -314,12 +322,17 @@
             data.read(iv, sizeof(iv));
 
             size_t totalSize = data.readInt32();
-            sp<IMemory> source =
+
+            SourceBuffer source;
+
+            source.mSharedMemory =
                 interface_cast<IMemory>(data.readStrongBinder());
-            if (source == NULL) {
+            if (source.mSharedMemory == NULL) {
                 reply->writeInt32(BAD_VALUE);
                 return OK;
             }
+            source.mHeapSeqNum = data.readInt32();
+
             int32_t offset = data.readInt32();
 
             int32_t numSubSamples = data.readInt32();
@@ -372,9 +385,9 @@
 
             if (overflow || sumSubsampleSizes != totalSize) {
                 result = -EINVAL;
-            } else if (totalSize > source->size()) {
+            } else if (totalSize > source.mSharedMemory->size()) {
                 result = -EINVAL;
-            } else if ((size_t)offset > source->size() - totalSize) {
+            } else if ((size_t)offset > source.mSharedMemory->size() - totalSize) {
                 result = -EINVAL;
             } else {
                 result = decrypt(key, iv, mode, pattern, source, offset,
@@ -428,16 +441,15 @@
             CHECK_INTERFACE(ICrypto, data, reply);
             sp<IMemoryHeap> heap =
                 interface_cast<IMemoryHeap>(data.readStrongBinder());
-            setHeap(heap);
+            reply->writeInt32(setHeap(heap));
             return OK;
         }
 
         case UNSET_HEAP:
         {
             CHECK_INTERFACE(ICrypto, data, reply);
-            sp<IMemoryHeap> heap =
-                interface_cast<IMemoryHeap>(data.readStrongBinder());
-            unsetHeap(heap);
+            int32_t seqNum = data.readInt32();
+            unsetHeap(seqNum);
             return OK;
         }