diff --git a/pkg/core/contract_state.go b/pkg/core/contract_state.go
index b5e736b7a..e3efdce27 100644
--- a/pkg/core/contract_state.go
+++ b/pkg/core/contract_state.go
@@ -39,11 +39,7 @@ func (a Contracts) commit(store storage.Store) error {
 // DecodeBinary implements Serializable interface.
 func (cs *ContractState) DecodeBinary(br *io.BinReader) {
 	cs.Script = br.ReadBytes()
-	paramBytes := br.ReadBytes()
-	cs.ParamList = make([]smartcontract.ParamType, len(paramBytes))
-	for k := range paramBytes {
-		cs.ParamList[k] = smartcontract.ParamType(paramBytes[k])
-	}
+	br.ReadArray(&cs.ParamList)
 	br.ReadLE(&cs.ReturnType)
 	br.ReadLE(&cs.Properties)
 	cs.Name = br.ReadString()
@@ -57,10 +53,7 @@ func (cs *ContractState) DecodeBinary(br *io.BinReader) {
 // EncodeBinary implements Serializable interface.
 func (cs *ContractState) EncodeBinary(bw *io.BinWriter) {
 	bw.WriteBytes(cs.Script)
-	bw.WriteVarUint(uint64(len(cs.ParamList)))
-	for k := range cs.ParamList {
-		bw.WriteLE(cs.ParamList[k])
-	}
+	bw.WriteArray(cs.ParamList)
 	bw.WriteLE(cs.ReturnType)
 	bw.WriteLE(cs.Properties)
 	bw.WriteString(cs.Name)
diff --git a/pkg/smartcontract/param_context.go b/pkg/smartcontract/param_context.go
index f7414f6a0..98d32a1f9 100644
--- a/pkg/smartcontract/param_context.go
+++ b/pkg/smartcontract/param_context.go
@@ -1,6 +1,9 @@
 package smartcontract
 
-import "github.com/CityOfZion/neo-go/pkg/util"
+import (
+	"github.com/CityOfZion/neo-go/pkg/io"
+	"github.com/CityOfZion/neo-go/pkg/util"
+)
 
 // ParamType represents the Type of the contract parameter.
 type ParamType byte
@@ -67,6 +70,16 @@ func (pt ParamType) MarshalJSON() ([]byte, error) {
 	return []byte(`"` + pt.String() + `"`), nil
 }
 
+// EncodeBinary implements io.Serializable interface.
+func (pt ParamType) EncodeBinary(w *io.BinWriter) {
+	w.WriteLE(pt)
+}
+
+// DecodeBinary implements io.Serializable interface.
+func (pt *ParamType) DecodeBinary(r *io.BinReader) {
+	r.ReadLE(pt)
+}
+
 // NewParameter returns a Parameter with proper initialized Value
 // of the given ParamType.
 func NewParameter(t ParamType) Parameter {