diff --git a/Script.js b/Script.js
index 62b485b32..a7d247127 100644
--- a/Script.js
+++ b/Script.js
@@ -170,32 +170,71 @@ function spec(b) {
 
   Script.prototype.writeOp = function (opcode)
   {
-    var buf = Put();
-    buf.put(this.buffer);
-    buf.word8(opcode);
-    this.buffer = buf.buffer();
+    var buf = Buffer(this.buffer.length + 1);
+    this.buffer.copy(buf);
+    buf.writeUInt8(opcode, this.buffer.length);
+
+    this.buffer = buf;
 
     this.chunks.push(opcode);
   };
 
+  Script.prototype.writeN = function (n)
+  {
+    if (n < 0 || n > 16)
+      throw new Error("writeN: out of range value " + n);
+
+    if (n == 0)
+      this.writeOp(OP_0);
+    else
+      this.writeOp(OP_1 + n - 1);
+  };
+
+  function prefixSize(data_length)
+  {
+    if (data_length < OP_PUSHDATA1) {
+      return 1;
+    } else if (data_length <= 0xff) {
+      return 1 + 1;
+    } else if (data_length <= 0xffff) {
+      return 1 + 2;
+    } else {
+      return 1 + 4;
+    }
+  };
+
+  function encodeLen(data_length) {
+    var buf = undefined;
+    if (data_length < OP_PUSHDATA1) {
+      buf = new Buffer(1);
+      buf.writeUInt8(data_length, 0);
+    }
+    
+    else if (data_length <= 0xff) {
+      buf = new Buffer(1 + 1);
+      buf.writeUInt8(OP_PUSHDATA1, 0);
+      buf.writeUInt8(data_length, 1);
+    }
+    
+    else if (data_length <= 0xffff) {
+      buf = new Buffer(1 + 2);
+      buf.writeUInt8(OP_PUSHDATA2, 0);
+      buf.writeUInt16LE(data_length, 1);
+    }
+    
+    else {
+      buf = new Buffer(1 + 4);
+      buf.writeUInt8(OP_PUSHDATA4, 0);
+      buf.writeUInt32LE(data_length, 1);
+    }
+
+    return buf;
+  };
+
   Script.prototype.writeBytes = function (data)
   {
-    var buf = Put();
-    buf.put(this.buffer);
-    if (data.length < OP_PUSHDATA1) {
-      buf.word8(data.length);
-    } else if (data.length <= 0xff) {
-      buf.word8(OP_PUSHDATA1);
-      buf.word8(data.length);
-    } else if (data.length <= 0xffff) {
-      buf.word8(OP_PUSHDATA2);
-      buf.word16le(data.length);
-    } else {
-      buf.word8(OP_PUSHDATA4);
-      buf.word32le(data.length);
-    }
-    buf.put(data);
-    this.buffer = buf.buffer();
+    var newSize = this.buffer.length + prefixSize(data.length) + data.length;
+    this.buffer = Buffer.concat([this.buffer, encodeLen(data.length), data]);
     this.chunks.push(data);
   };
 
@@ -256,6 +295,25 @@ function spec(b) {
     return script;
   };
 
+  Script.createMultisig = function(n_required, keys) {
+    var script = new Script();
+    script.writeN(n_required);
+    keys.forEach(function(key) {
+    	script.writeBytes(key);
+    });
+    script.writeN(keys.length);
+    script.writeOp(OP_CHECKMULTISIG);
+    return script;
+  };
+
+  Script.createP2SH = function(scriptHash) {
+    var script = new Script();
+    script.writeOp(OP_HASH160);
+    script.writeBytes(scriptHash);
+    script.writeOp(OP_EQUAL);
+    return script;
+  };
+
   Script.fromTestData = function (testData) {
     testData = testData.map(function (chunk) {
       if ("string" === typeof chunk) {
diff --git a/Wallet.js b/Wallet.js
index 5178c577a..ac5a290d0 100644
--- a/Wallet.js
+++ b/Wallet.js
@@ -1,9 +1,12 @@
 require('classtool');
+var hex = function(hex) {return new Buffer(hex, 'hex');};
 
 function ClassSpec(b) {
 	var fs = require('fs');
 	var EncFile = require('./util/EncFile');
+	var Address = require('./Address').class();
 	var networks = require('./networks');
+  	var util = b.util || require('./util/util');
 	var ENC_METHOD = 'aes-256-cbc';
 
 	var skeleton = {
@@ -14,6 +17,7 @@ function ClassSpec(b) {
 		best_hash: null,
 		best_height: -1,
 		keys: [],
+		scripts: {},
 	};
 
 	function Wallet(cfg) {
@@ -72,6 +76,60 @@ function ClassSpec(b) {
 		this.dirty = true;
 	};
 
+	Wallet.prototype.findKeyHash = function(pubKeyHash) {
+		var pkhStr = pubKeyHash.toString();
+
+		for (var i = 0; i < this.datastore.keys.length; i++) {
+			var obj = this.datastore.keys[i];
+			var addrStr = obj.addr;
+			var addr = new Address(addrStr);
+			if (addr.payload().toString() == pkhStr)
+				return obj;
+		}
+
+		return undefined;
+	};
+
+	Wallet.prototype.expandKey = function(key) {
+		var addr = new Address(key);
+		var isAddr = true;
+
+		try {
+			addr.validate();
+			var b = addr.payload();
+			var obj = this.findKeyHash(b);
+			key = obj.pub;
+		} catch(e) {
+			// do nothing
+		}
+
+		var re = /^[a-fA-F0-9]+$/;
+		if (!key.match(re))
+			throw new Error("Unknown key type");
+		return hex(key);
+	};
+
+	Wallet.prototype.expandKeys = function(keys) {
+		var res = [];
+		var us = this;
+		keys.forEach(function(key) {
+			var expKey = us.expandKey(key);
+			res.push(expKey);
+		});
+		return res;
+	};
+
+	Wallet.prototype.addScript = function(script) {
+		var buf = script.getBuffer();
+		var hash = util.sha256ripe160(buf);
+		var addr = new Address(this.network.addressScript, hash);
+		var addrStr = addr.as('base58');
+		this.datastore.scripts[addrStr] = buf.toString('hex');
+		this.dirty = true;
+
+		return addrStr;
+	};
+
 	return Wallet;
 };
 module.defineClass(ClassSpec);