diff --git a/drm/mediadrm/plugins/clearkey/DrmPlugin.h b/drm/mediadrm/plugins/clearkey/DrmPlugin.h
index d5a47ca..58421b9 100644
--- a/drm/mediadrm/plugins/clearkey/DrmPlugin.h
+++ b/drm/mediadrm/plugins/clearkey/DrmPlugin.h
@@ -63,22 +63,28 @@
             Vector<uint8_t>& keySetId);
 
     virtual status_t removeKeys(const Vector<uint8_t>& sessionId) {
-        UNUSED(sessionId);
+        if (sessionId.size() == 0) {
+            return android::BAD_VALUE;
+        }
+
         return android::ERROR_DRM_CANNOT_HANDLE;
     }
 
     virtual status_t restoreKeys(
             const Vector<uint8_t>& sessionId,
             const Vector<uint8_t>& keySetId) {
-        UNUSED(sessionId);
-        UNUSED(keySetId);
+        if (sessionId.size() == 0 || keySetId.size() == 0) {
+            return android::BAD_VALUE;
+        }
         return android::ERROR_DRM_CANNOT_HANDLE;
     }
 
     virtual status_t queryKeyStatus(
             const Vector<uint8_t>& sessionId,
             KeyedVector<String8, String8>& infoMap) const {
-        UNUSED(sessionId);
+        if (sessionId.size() == 0) {
+            return android::BAD_VALUE;
+        }
         UNUSED(infoMap);
         return android::ERROR_DRM_CANNOT_HANDLE;
     }
@@ -179,10 +185,10 @@
             const Vector<uint8_t>& input,
             const Vector<uint8_t>& iv,
             Vector<uint8_t>& output) {
-        UNUSED(sessionId);
-        UNUSED(keyId);
-        UNUSED(input);
-        UNUSED(iv);
+        if (sessionId.size() == 0 || keyId.size() == 0 ||
+                input.size() == 0 || iv.size() == 0) {
+            return android::BAD_VALUE;
+        }
         UNUSED(output);
         return android::ERROR_DRM_CANNOT_HANDLE;
     }
@@ -193,10 +199,10 @@
             const Vector<uint8_t>& input,
             const Vector<uint8_t>& iv,
             Vector<uint8_t>& output) {
-        UNUSED(sessionId);
-        UNUSED(keyId);
-        UNUSED(input);
-        UNUSED(iv);
+        if (sessionId.size() == 0 || keyId.size() == 0 ||
+                input.size() == 0 || iv.size() == 0) {
+            return android::BAD_VALUE;
+        }
         UNUSED(output);
         return android::ERROR_DRM_CANNOT_HANDLE;
     }
@@ -206,9 +212,10 @@
             const Vector<uint8_t>& keyId,
             const Vector<uint8_t>& message,
             Vector<uint8_t>& signature) {
-        UNUSED(sessionId);
-        UNUSED(keyId);
-        UNUSED(message);
+        if (sessionId.size() == 0 || keyId.size() == 0 ||
+                message.size() == 0) {
+            return android::BAD_VALUE;
+        }
         UNUSED(signature);
         return android::ERROR_DRM_CANNOT_HANDLE;
     }
@@ -218,10 +225,10 @@
             const Vector<uint8_t>& keyId,
             const Vector<uint8_t>& message,
             const Vector<uint8_t>& signature, bool& match) {
-        UNUSED(sessionId);
-        UNUSED(keyId);
-        UNUSED(message);
-        UNUSED(signature);
+        if (sessionId.size() == 0 || keyId.size() == 0 ||
+                message.size() == 0 || signature.size() == 0) {
+            return android::BAD_VALUE;
+        }
         UNUSED(match);
         return android::ERROR_DRM_CANNOT_HANDLE;
     }
@@ -232,10 +239,10 @@
             const Vector<uint8_t>& message,
             const Vector<uint8_t>& wrappedKey,
             Vector<uint8_t>& signature) {
-        UNUSED(sessionId);
-        UNUSED(algorithm);
-        UNUSED(message);
-        UNUSED(wrappedKey);
+        if (sessionId.size() == 0 || algorithm.size() == 0 ||
+                message.size() == 0 || wrappedKey.size() == 0) {
+            return android::BAD_VALUE;
+        }
         UNUSED(signature);
         return android::ERROR_DRM_CANNOT_HANDLE;
     }