diff --git a/lib/bcoin/protocol/constants.js b/lib/bcoin/protocol/constants.js
index e22dcb83..ba25f547 100644
--- a/lib/bcoin/protocol/constants.js
+++ b/lib/bcoin/protocol/constants.js
@@ -59,7 +59,7 @@ exports.opcodes = {
   pushdata4: 0x4e,
   negate1: 0x4f,
 
-  nop: 0x61,
+  nop1: 0x61,
   if_: 0x63,
   notif: 0x64,
   else_: 0x67,
@@ -144,8 +144,14 @@ exports.opcodes = {
 for (var i = 1; i <= 16; i++)
   exports.opcodes[i] = 0x50 + i;
 
-exports.opcodes['false'] = exports.opcodes['0'];
-exports.opcodes['true'] = exports.opcodes['1'];
+for (var i = 0; i <= 7; i++)
+  exports.opcodes['nop' + (i + 3)] = 0xb2 + i;
+
+// exports.opcodes['false'] = exports.opcodes['0'];
+// exports.opcodes['true'] = exports.opcodes['1'];
+
+// exports.opcodes['if'] = exports.opcodes.if_;
+// exports.opcodes['else'] = exports.opcodes.else_;
 
 exports.opcodesByVal = new Array(256);
 Object.keys(exports.opcodes).forEach(function(name) {
diff --git a/lib/bcoin/script.js b/lib/bcoin/script.js
index dd1eb65f..b2501be7 100644
--- a/lib/bcoin/script.js
+++ b/lib/bcoin/script.js
@@ -135,9 +135,15 @@ script.execute = function execute(s, stack, tx, index) {
     return false;
 
   var input = tx.inputs[index];
+  var lastSep = -1;
+
+  stack.alt = stack.alt || [];
+
+  // TODO: if statements
 
   for (var pc = 0; pc < s.length; pc++) {
     var o = s[pc];
+
     if (Array.isArray(o)) {
       stack.push(o);
     } else if (typeof o === 'number' && o >= 1 && o <= 16) {
@@ -148,7 +154,287 @@ script.execute = function execute(s, stack, tx, index) {
 
       stack.push(stack[stack.length - 1]);
     } else if (o === 'drop') {
+      if (stack.length === 0)
+        return false;
+
       stack.pop();
+    } else if (o === 'nop1' || o === 'nop3' || o === 'nop4'
+      || o === 'nop5' || o === 'nop6' || o === 'nop7'
+      || o === 'nop8' || o === 'nop9' || o === 'nop10') {
+      ;
+      // OP_EVAL
+      // if (o === 'nop1') {
+      //   var evalScript = script.decode(stack.pop());
+      //   var res = script.execute(evalScript, stack, tx, index);
+      //   if (!res)
+      //     return false;
+      // }
+    } else if (o === 'verify') {
+      if (stack.length === 0)
+        return false;
+      if (new bn(stack[stack.length - 1]).cmp(0) === 0)
+        return false;
+    } else if (o === 'return') {
+      return false;
+    } else if (o === 'toaltstack') {
+      if (stack.length === 0)
+        return false;
+      stack.alt.push(stack.pop());
+    } else if (o === 'fromaltstack') {
+      if (stack.alt.length === 0)
+        return false;
+      stack.push(stack.alt.pop());
+    } else if (o === 'ifdup') {
+      if (stack.length === 0)
+        return false;
+      if (new bn(stack[stack.length - 1]).cmp(0) !== 0)
+        stack.push(new bn(stack[stack.length - 1]).toArray());
+    } else if (o === 'depth') {
+      stack.push(new bn(stack.length).toArray());
+    } else if (o === 'nip') {
+      if (stack.length < 2)
+        return false;
+      stack.splice(stack.length - 2, 1);
+    } else if (o === 'over') {
+      if (stack.length < 2)
+        return false;
+      stack.push(stack[stack.length - 2]);
+    } else if (o === 'pick' || o === 'roll') {
+      if (stack.length < 2)
+        return false;
+      var n = new bn(stack.pop()).toNumber();
+      if (n < 0 || n >= stack.length)
+        return false;
+      var v = stack[-n - 1];
+      if (o === 'roll')
+        stack.splice(stack.length - n - 1, 1);
+      stack.push(v);
+    } else if (o === 'rot') {
+      if (stack.length < 3)
+        return false;
+      var v3 = stack[stack.length - 3];
+      var v2 = stack[stack.length - 2];
+      var v1 = stack[stack.length - 1];
+      stack[stack.length - 3] = v2;
+      stack[stack.length - 2] = v3;
+
+      v2 = stack[stack.length - 2];
+      stack[stack.length - 2] = v1;
+      stack[stack.length - 1] = v2;
+    } else if (o === 'swap') {
+      if (stack.length < 2)
+        return false;
+      var v2 = stack[stack.length - 2];
+      var v1 = stack[stack.length - 1];
+      stack[stack.length - 2] = v1;
+      stack[stack.length - 1] = v2;
+    } else if (o === 'tuck') {
+      if (stack.length < 2)
+        return false;
+      stack.splice(stack.length - 2, 0, stack[stack.length - 1]);
+    } else if (o === 'drop2') {
+      if (stack.length < 2)
+        return false;
+      stack.pop();
+      stack.pop();
+    } else if (o === 'dup2') {
+      if (stack.length < 2)
+        return false;
+      var v1 = stack[stack.length - 1];
+      var v2 = stack[stack.length - 2];
+      stack.push(v1);
+      stack.push(v2);
+    } else if (o === 'dup3') {
+      if (stack.length < 3)
+        return false;
+      var v1 = stack[stack.length - 1];
+      var v2 = stack[stack.length - 2];
+      var v3 = stack[stack.length - 3];
+      stack.push(v1);
+      stack.push(v2);
+      stack.push(v3);
+    } else if (o === 'over2') {
+      if (stack.length < 4)
+        return false;
+      var v1 = stack[stack.length - 4];
+      var v2 = stack[stack.length - 3];
+      stack.push(v1);
+      stack.push(v2);
+    } else if (o === 'rot2') {
+      if (stack.length < 6)
+        return false;
+      var v1 = stack[stack.length - 6];
+      var v2 = stack[stack.length - 5];
+      stack.splice(stack.length - 6, 2);
+      stack.push(v1);
+      stack.push(v2);
+    } else if (o === 'swap2') {
+      if (stack.length < 4)
+        return false;
+      var v4 = stack[stack.length - 4];
+      var v3 = stack[stack.length - 3];
+      var v2 = stack[stack.length - 2];
+      var v1 = stack[stack.length - 1];
+      stack[stack.length - 4] = v2;
+      stack[stack.length - 2] = v4;
+      stack[stack.length - 3] = v1;
+      stack[stack.length - 1] = v3;
+    } else if (o === 'size') {
+      if (stack.length < 1)
+        return false;
+      stack.push(new bn(stack[stack.length - 1].length || 0).toArray());
+    } else if (o === 'add1'
+      || o === 'sub1'
+      || o === 'negate'
+      || o === 'abs'
+      || o === 'not'
+      || o === 'noteq0') {
+      if (stack.length < 1)
+        return false;
+      var n = new bn(stack.pop());
+      switch (o) {
+        case 'add1':
+          n.iadd(1);
+          break;
+        case 'sub1':
+          n.isub(1);
+          break;
+        case 'negate':
+          n = n.neg();
+          break;
+        case 'abs':
+          if (n.cmp(0) < 0)
+            n = n.neg();
+          break;
+        case 'not':
+          n = n.cmp(0) === 0;
+          break;
+        case 'noteq0':
+          n = n.cmp(0) !== 0;
+          break;
+        default:
+          return false;
+      }
+      stack.push(n.toArray());
+    } else if (o === 'add'
+      || o === 'sub'
+      || o === 'booland'
+      || o === 'boolor'
+      || o === 'numeq'
+      || o === 'numeqverify'
+      || o === 'numneq'
+      || o === 'lt'
+      || o === 'gt'
+      || o === 'lte'
+      || o === 'gte'
+      || o === 'min'
+      || o === 'max') {
+      switch (o) {
+        case 'add':
+        case 'sub':
+        case 'booland':
+        case 'boolor':
+        case 'numeq':
+        case 'numeqverify':
+        case 'numneq':
+        case 'lt':
+        case 'gt':
+        case 'lte':
+        case 'gte':
+        case 'min':
+        case 'max':
+          if (stack.length < 2)
+            return false;
+          var n2 = new bn(stack.pop());
+          var n1 = new bn(stack.pop());
+          var n = new bn(0);
+          switch (o) {
+            case 'add':
+              n = n1.add(b2);
+              break;
+            case 'sub':
+              n = n1.sub(n2);
+              break;
+            case 'booland':
+              n = n1.cmp(0) !== 0 && n2.cmp(0) !== 0;
+              break;
+            case 'boolor':
+              n = n1.cmp(0) !== 0 || n2.cmp(0) !== 0;
+              break;
+            case 'numeq':
+              n = n1.cmp(n2) === 0;
+              break;
+            case 'numeqverify':
+              n = n1.cmp(n2) === 0;
+              break;
+            case 'numneq':
+              n = n1.cmp(n2) !== 0;
+              break;
+            case 'lt':
+              n = n1.cmp(n2) < 0;
+              break;
+            case 'gt':
+              n = n1.cmp(n2) > 0;
+              break;
+            case 'lte':
+              n = n1.cmp(n2) <= 0;
+              break;
+            case 'gte':
+              n = n1.cmp(n2) >= 0;
+              break;
+            case 'min':
+              n = n1.cmp(n2) < 0 ? n1 : n2;
+              break;
+            case 'max':
+              n = n1.cmp(n2) > 0 ? n1 : n2;
+              break;
+            default:
+              return false;
+          }
+          var res = n.cmp(0) !== 0;
+          if (o === 'numeqverify') {
+            if (!res)
+              return false;
+          } else {
+            stack.push(n.toArray());
+            // stack.push(res ? [ 1 ] : []);
+          }
+          // stack.push(n.toArray());
+          // if (op == 'numeqverify') {
+          //   if (n.cmp(0) !== 0)
+          //     stack.pop();
+          //   else
+          //     return false;
+          // }
+          break;
+        case 'within':
+          if (stack.length < 3)
+            return false;
+          var n3 = new bn(stack.pop());
+          var n2 = new bn(stack.pop());
+          var n1 = new bn(stack.pop());
+          var val = n2.cmp(n1) <= 0 && n1.cmp(n3) < 0;
+          stack.push(val.cmp(0) !== 0 ? [ 1 ] : []);
+          break;
+      }
+    } else if (o === 'codesep') {
+      lastSep = pc;
+    } else if (o === 'ripemd160') {
+      if (stack.length === 0)
+        return false;
+      stack.push(utils.ripemd160(stack.pop()));
+    } else if (o === 'sha1') {
+      if (stack.length === 0)
+        return false;
+      stack.push(utils.sha1(stack.pop()));
+    } else if (o === 'sha256') {
+      if (stack.length === 0)
+        return false;
+      stack.push(utils.sha256(stack.pop()));
+    } else if (o === 'hash256') {
+      if (stack.length === 0)
+        return false;
+      stack.push(utils.dsha256(stack.pop()));
     } else if (o === 'hash160') {
       if (stack.length === 0)
         return false;
@@ -165,7 +451,6 @@ script.execute = function execute(s, stack, tx, index) {
       } else {
         stack.push(res ? [ 1 ] : []);
       }
-
     } else if (o === 'checksigverify' || o === 'checksig') {
       if (!tx || stack.length < 2)
         return false;
@@ -179,7 +464,8 @@ script.execute = function execute(s, stack, tx, index) {
       if (!script.isValidSig(sig))
         return false;
 
-      var subscript = input.out.tx.getSubscript(input.out.index);
+      // var subscript = input.out.tx.getSubscript(input.out.index);
+      var subscript = s.slice(lastSep + 1);
       var hash = tx.subscriptHash(index, subscript, type);
 
       var res = script.verify(hash, sig.slice(0, -1), pub);
@@ -227,7 +513,8 @@ script.execute = function execute(s, stack, tx, index) {
         if (!constants.rhashType[type & 0x7f])
           return false;
 
-        var subscript = input.out.tx.getSubscript(input.out.index);
+        // var subscript = input.out.tx.getSubscript(input.out.index);
+        var subscript = s.slice(lastSep + 1);
         var hash = tx.subscriptHash(index, subscript, type);
 
         if (!script.isValidSig(sig))
@@ -260,11 +547,7 @@ script.execute = function execute(s, stack, tx, index) {
       if (stack.length === 0)
         return false;
 
-      var lock = stack[stack.length - 1];
-      if (lock.length !== 1)
-        return false;
-
-      lock = lock[0];
+      var lock = new bn(stack[stack.length - 1]).toNumber();
 
       if (lock < 0)
         return false;
@@ -288,7 +571,7 @@ script.execute = function execute(s, stack, tx, index) {
     }
   }
 
-  if (stack.length > 1000)
+  if (stack.length + stack.alt.length > 1000)
     return false;
 
   return true;
diff --git a/lib/bcoin/utils.js b/lib/bcoin/utils.js
index f96ded1c..d4566c6e 100644
--- a/lib/bcoin/utils.js
+++ b/lib/bcoin/utils.js
@@ -118,6 +118,14 @@ utils.fromBase58 = function fromBase58(str) {
   return z.concat(res.toArray());
 };
 
+utils.ripemd160 = function ripemd160(data, enc) {
+  return hash.ripemd160().update(data, enc).digest();
+};
+
+utils.sha1 = function sha1(data, enc) {
+  return hash.sha1().update(data, enc).digest();
+};
+
 utils.ripesha = function ripesha(data, enc) {
   return hash.ripemd160().update(utils.sha256(data, enc)).digest();
 };