diff --git a/libwvdrmengine/include/WVErrors.h b/libwvdrmengine/include/WVErrors.h
index 93193c1a..f45eebc1 100644
--- a/libwvdrmengine/include/WVErrors.h
+++ b/libwvdrmengine/include/WVErrors.h
@@ -10,12 +10,19 @@
 namespace wvdrm {
 
 using android::ERROR_DRM_VENDOR_MIN;
+using android::ERROR_DRM_VENDOR_MAX;
 
 enum {
-  kErrorNeedProvisioning       = ERROR_DRM_VENDOR_MIN,
-  kErrorDeviceRevoked          = ERROR_DRM_VENDOR_MIN + 1,
-  kErrorIncorrectBufferSize    = ERROR_DRM_VENDOR_MIN + 2,
-  kErrorCDMGeneric             = ERROR_DRM_VENDOR_MIN + 3,
+  kErrorNeedProvisioning        = ERROR_DRM_VENDOR_MIN,
+  kErrorDeviceRevoked           = ERROR_DRM_VENDOR_MIN + 1,
+  kErrorIncorrectBufferSize     = ERROR_DRM_VENDOR_MIN + 2,
+  kErrorCDMGeneric              = ERROR_DRM_VENDOR_MIN + 3,
+  kErrorUnsupportedCrypto       = ERROR_DRM_VENDOR_MIN + 4,
+  kErrorCannotGuaranteeSecurity = ERROR_DRM_VENDOR_MIN + 5,
+  kErrorExpectedUnencrypted     = ERROR_DRM_VENDOR_MIN + 6,
+
+  // Used by crypto test mode
+  kErrorTestMode                = ERROR_DRM_VENDOR_MAX,
 };
 
 } // namespace wvdrm
diff --git a/libwvdrmengine/mediacrypto/src/WVCryptoPlugin.cpp b/libwvdrmengine/mediacrypto/src/WVCryptoPlugin.cpp
index 30ad844b..a8ae4511 100644
--- a/libwvdrmengine/mediacrypto/src/WVCryptoPlugin.cpp
+++ b/libwvdrmengine/mediacrypto/src/WVCryptoPlugin.cpp
@@ -18,6 +18,7 @@
 #include "utils/Errors.h"
 #include "utils/String8.h"
 #include "wv_cdm_constants.h"
+#include "WVErrors.h"
 
 namespace wvdrm {
 
@@ -71,7 +72,8 @@ ssize_t WVCryptoPlugin::decrypt(bool secure, const uint8_t key[KEY_ID_SIZE],
                                 size_t numSubSamples, void* dstPtr,
                                 AString* errorDetailMsg) {
   if (mode != kMode_Unencrypted && mode != kMode_AES_CTR) {
-    return ERROR_DRM_CANNOT_HANDLE;
+    errorDetailMsg->setTo("Encryption mode is not supported by Widevine CDM.");
+    return kErrorUnsupportedCrypto;
   }
 
   // If the caller requested secure decrypt, verify that we can comply.
@@ -82,10 +84,12 @@ ssize_t WVCryptoPlugin::decrypt(bool secure, const uint8_t key[KEY_ID_SIZE],
 
     if (!isCdmResponseTypeSuccess(res)) {
       ALOGE("Error querying CDM status: %u", res);
-      return ERROR_DRM_CANNOT_HANDLE;
+      errorDetailMsg->setTo("Unable to verify ability to decode securely.");
+      return kErrorCannotGuaranteeSecurity;
     } else if (status[QUERY_KEY_SECURITY_LEVEL] !=
                QUERY_VALUE_SECURITY_LEVEL_L1) {
-      return ERROR_DRM_CANNOT_HANDLE;
+      errorDetailMsg->setTo("Secure decode is not supported on this device.");
+      return kErrorCannotGuaranteeSecurity;
     }
   }
 
@@ -103,7 +107,9 @@ ssize_t WVCryptoPlugin::decrypt(bool secure, const uint8_t key[KEY_ID_SIZE],
     const SubSample &subSample = subSamples[i];
 
     if (mode == kMode_Unencrypted && subSample.mNumBytesOfEncryptedData != 0) {
-      return ERROR_DRM_DECRYPT;
+      errorDetailMsg->setTo("Encrypted subsamples found in allegedly "
+                            "unencrypted data.");
+      return kErrorExpectedUnencrypted;
     }
 
     // "Decrypt" any unencrypted data.  Per the ISO-CENC standard, clear data
@@ -117,7 +123,8 @@ ssize_t WVCryptoPlugin::decrypt(bool secure, const uint8_t key[KEY_ID_SIZE],
       if (!isCdmResponseTypeSuccess(res)) {
         ALOGE("Decrypt error result in session %s during unencrypted block: %d",
               mSessionId.c_str(), res);
-        return mapCdmResponseType(res);
+        errorDetailMsg->setTo("Error decrypting data.");
+        return kErrorCDMGeneric;
       }
 
       offset += subSample.mNumBytesOfClearData;
@@ -134,7 +141,8 @@ ssize_t WVCryptoPlugin::decrypt(bool secure, const uint8_t key[KEY_ID_SIZE],
       if (!isCdmResponseTypeSuccess(res)) {
         ALOGE("Decrypt error result in session %s during encrypted block: %d",
               mSessionId.c_str(), res);
-        return mapCdmResponseType(res);
+        errorDetailMsg->setTo("Error decrypting data.");
+        return kErrorCDMGeneric;
       }
 
       offset += subSample.mNumBytesOfEncryptedData;
@@ -158,8 +166,8 @@ ssize_t WVCryptoPlugin::decrypt(bool secure, const uint8_t key[KEY_ID_SIZE],
           buf.appendFormat("%02x", digest[i]);
       }
 
-      *errorDetailMsg = AString(buf.string());
-      return ERROR_DRM_VENDOR_MIN;
+      errorDetailMsg->setTo(buf.string());
+      return kErrorTestMode;
   }
 
 
diff --git a/libwvdrmengine/mediacrypto/test/WVCryptoPlugin_test.cpp b/libwvdrmengine/mediacrypto/test/WVCryptoPlugin_test.cpp
index d5cc7db7..936b2414 100644
--- a/libwvdrmengine/mediacrypto/test/WVCryptoPlugin_test.cpp
+++ b/libwvdrmengine/mediacrypto/test/WVCryptoPlugin_test.cpp
@@ -107,12 +107,17 @@ TEST_F(WVCryptoPluginTest, RejectsSecureDecodeOnL3) {
       .WillOnce(DoAll(SetArgPointee<0>(l3Map),
                       Return(wvcdm::NO_ERROR)));
 
-  ssize_t res = plugin.decrypt(true, keyId, iv, CryptoPlugin::kMode_AES_CTR,
-                               in, subSamples, kSubSampleCount, out, NULL);
+  AString errorDetailMessage;
 
-  EXPECT_LT(res, static_cast<ssize_t>(0)) <<
+  ssize_t res = plugin.decrypt(true, keyId, iv, CryptoPlugin::kMode_AES_CTR,
+                               in, subSamples, kSubSampleCount, out,
+                               &errorDetailMessage);
+
+  EXPECT_LT(res, 0) <<
       "WVCryptoPlugin allowed decryption to proceed despite being asked for an "
       "unsupported security level";
+  EXPECT_GT(errorDetailMessage.size(), 0u) <<
+      "WVCryptoPlugin did not report a detailed error message.";
 }
 
 TEST_F(WVCryptoPluginTest, AttemptsToDecrypt) {
@@ -144,9 +149,14 @@ TEST_F(WVCryptoPluginTest, AttemptsToDecrypt) {
         .WillOnce(Return(wvcdm::NO_ERROR));
   }
 
+  AString errorDetailMessage;
+
   ssize_t res = plugin.decrypt(false, keyId, iv, CryptoPlugin::kMode_AES_CTR,
-                               in, subSamples, kSubSampleCount, out, NULL);
+                               in, subSamples, kSubSampleCount, out,
+                               &errorDetailMessage);
 
   EXPECT_EQ(static_cast<ssize_t>(kDataSize), res) <<
       "WVCryptoPlugin decrypted the wrong number of bytes";
+  EXPECT_EQ(0u, errorDetailMessage.size()) <<
+      "WVCryptoPlugin reported a detailed error message.";
 }
\ No newline at end of file