diff --git a/core/chaincode/handler.go b/core/chaincode/handler.go
index 240e414d651..591f66f0b40 100644
--- a/core/chaincode/handler.go
+++ b/core/chaincode/handler.go
@@ -636,8 +636,7 @@ func (handler *Handler) handleRangeQueryState(msg *pb.ChaincodeMessage) {
 			if qresult == nil {
 				break
 			}
-			//PDMP - let it panic if not KV
-			kv := qresult.(ledger.KV)
+			kv := qresult.(*ledger.KV)
 			keyAndValue := pb.RangeQueryStateKeyValue{Key: kv.Key, Value: kv.Value}
 			keysAndValues = append(keysAndValues, &keyAndValue)
 		}
@@ -735,8 +734,7 @@ func (handler *Handler) handleRangeQueryStateNext(msg *pb.ChaincodeMessage) {
 			if qresult != nil {
 				break
 			}
-			//PDMP - let it panic if not KV
-			kv := qresult.(ledger.KV)
+			kv := qresult.(*ledger.KV)
 			keyAndValue := pb.RangeQueryStateKeyValue{Key: kv.Key, Value: kv.Value}
 			keysAndValues = append(keysAndValues, &keyAndValue)
 		}
diff --git a/peer/chaincode/common_test.go b/peer/chaincode/common_test.go
index 33dc564ffbe..2de1dde15c9 100644
--- a/peer/chaincode/common_test.go
+++ b/peer/chaincode/common_test.go
@@ -17,8 +17,10 @@
 package chaincode
 
 import (
+	"encoding/json"
 	"testing"
 
+	pb "github.com/hyperledger/fabric/protos/peer"
 	"github.com/stretchr/testify/require"
 )
 
@@ -76,3 +78,52 @@ func TestCheckChaincodeCmdParamsEmptyCtor(t *testing.T) {
 
 	require.Error(result)
 }
+
+func TestCheckValidJSON(t *testing.T) {
+	validJSON := `{"Args":["a","b","c"]}`
+	input := &pb.ChaincodeInput{}
+	if err := json.Unmarshal([]byte(validJSON), &input); err != nil {
+		t.Fail()
+		t.Logf("Chaincode argument error: %s", err)
+		return
+	}
+
+	validJSON = `{"Function":"f", "Args":["a","b","c"]}`
+	if err := json.Unmarshal([]byte(validJSON), &input); err != nil {
+		t.Fail()
+		t.Logf("Chaincode argument error: %s", err)
+		return
+	}
+
+	validJSON = `{"Function":"f", "Args":[]}`
+	if err := json.Unmarshal([]byte(validJSON), &input); err != nil {
+		t.Fail()
+		t.Logf("Chaincode argument error: %s", err)
+		return
+	}
+
+	validJSON = `{"Function":"f"}`
+	if err := json.Unmarshal([]byte(validJSON), &input); err != nil {
+		t.Fail()
+		t.Logf("Chaincode argument error: %s", err)
+		return
+	}
+}
+
+func TestCheckInvalidJSON(t *testing.T) {
+	invalidJSON := `{["a","b","c"]}`
+	input := &pb.ChaincodeInput{}
+	if err := json.Unmarshal([]byte(invalidJSON), &input); err == nil {
+		t.Fail()
+		t.Logf("Bar argument error should have been caught: %s", invalidJSON)
+		return
+	}
+
+	invalidJSON = `{"Function":}`
+	if err := json.Unmarshal([]byte(invalidJSON), &input); err == nil {
+		t.Fail()
+		t.Logf("Chaincode argument error: %s", err)
+		t.Logf("Bar argument error should have been caught: %s", invalidJSON)
+		return
+	}
+}
diff --git a/protos/peer/chaincodeunmarshall.go b/protos/peer/chaincodeunmarshall.go
new file mode 100644
index 00000000000..97ae74e177d
--- /dev/null
+++ b/protos/peer/chaincodeunmarshall.go
@@ -0,0 +1,44 @@
+/*
+Copyright IBM Corp. 2016 All Rights Reserved.
+
+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.
+*/
+
+package peer
+
+import (
+	"encoding/json"
+
+	"github.com/hyperledger/fabric/core/util"
+)
+
+type strArgs struct {
+	Function string
+	Args     []string
+}
+
+// UnmarshalJSON converts the string-based REST/JSON input to
+// the []byte-based current ChaincodeInput structure.
+func (c *ChaincodeInput) UnmarshalJSON(b []byte) error {
+	sa := &strArgs{}
+	err := json.Unmarshal(b, sa)
+	if err != nil {
+		return err
+	}
+	allArgs := sa.Args
+	if sa.Function != "" {
+		allArgs = append([]string{sa.Function}, sa.Args...)
+	}
+	c.Args = util.ToChaincodeArgs(allArgs...)
+	return nil
+}