diff --git a/keystore/IKeystoreService.cpp b/keystore/IKeystoreService.cpp
index 64d953f..9db6696 100644
--- a/keystore/IKeystoreService.cpp
+++ b/keystore/IKeystoreService.cpp
@@ -655,7 +655,7 @@
                 memcpy(buf, out, outSize);
                 free(out);
             } else {
-                reply->writeInt32(0);
+                reply->writeInt32(-1);
             }
             reply->writeInt32(ret);
             return NO_ERROR;
@@ -698,7 +698,7 @@
                 memcpy(buf, out, outSize);
                 free(out);
             } else {
-                reply->writeInt32(0);
+                reply->writeInt32(-1);
             }
             reply->writeInt32(ret);
             return NO_ERROR;