diff --git a/js/security/Witness.js b/js/security/Witness.js
new file mode 100644
index 0000000..3b88f06
--- /dev/null
+++ b/js/security/Witness.js
@@ -0,0 +1,29 @@
+/** 
+ * @author: Wentao Shang
+ * See COPYING for copyright and distribution information.
+ */
+
+var MerklePath = function MerkelPath() {
+	this.index = null;  // int
+	this.digestList = [];  // array of hex string
+};
+
+var Witness = function Witness() {
+	this.oid = null;  // string
+	this.path = new MerklePath();  // MerklePath
+};
+
+Witness.prototype.decode = function(/* Uint8Array */ witness) {
+	var wit = DataUtils.toHex(witness).toLowerCase();
+	var der = Hex.decode(wit);
+	var asn1 = ASN1.decode(der);
+	//console.log(asn1.toPrettyString());
+	
+	this.oid = asn1.sub[0].sub[0].content();  // OID
+	this.path.index = asn1.sub[1].sub[0].sub[0].content();  // index
+	for (i = 0; i < asn1.sub[1].sub[0].sub[1].sub.length; i++) {
+		pos = asn1.sub[1].sub[0].sub[1].sub[i].stream.pos;
+		str = wit.substring(2 * pos + 4, 2 * pos + 68);
+		this.path.digestList.push(str);  // digest hex string
+	}
+};