Index: src/script/interpreter.cpp
===================================================================
--- src/script/interpreter.cpp
+++ src/script/interpreter.cpp
@@ -335,9 +335,8 @@
                 return set_error(serror, SCRIPT_ERR_OP_COUNT);
             }
 
-            if (opcode == OP_RIGHT || opcode == OP_INVERT || opcode == OP_2MUL ||
-                opcode == OP_2DIV || opcode == OP_MUL || opcode == OP_LSHIFT ||
-                opcode == OP_RSHIFT) {
+            if (opcode == OP_INVERT || opcode == OP_2MUL || opcode == OP_2DIV ||
+                opcode == OP_MUL || opcode == OP_LSHIFT || opcode == OP_RSHIFT) {
                 // Disabled opcodes.
                 return set_error(serror, SCRIPT_ERR_DISABLED_OPCODE);
             }
@@ -1306,6 +1305,39 @@
                         stack.push_back(num.getvch());
                     } break;
 
+                    case OP_NUM2BIN: {
+                        if (stack.size() < 2) {
+                            return set_error(serror, SCRIPT_ERR_INVALID_STACK_OPERATION);
+                        }
+                        CScriptNum bn(stacktop(-2), fRequireMinimal);
+                        int64_t sz = CScriptNum(stacktop(-1), fRequireMinimal).getint();
+                        if (sz<1 || static_cast<uint64_t>(sz) > CScriptNum::nDefaultMaxNumSize) {
+                            return set_error(serror, SCRIPT_ERR_INVALID_NUM2BIN_OPERATION);
+                        }
+                        valtype v=bn.getvch(); //LE
+                        if (static_cast<uint64_t>(sz) < v.size()) {
+                            return set_error(serror, SCRIPT_ERR_INVALID_NUM2BIN_OPERATION);
+                        }
+                        valtype ans;
+                        ans.reserve(sz);
+                        bool neg{false};
+                        if (!v.empty()) {
+                            neg=*v.rbegin()&0x80;
+                            *v.rbegin()&=~0x80; //make it positive
+                        }
+                        size_t pad=sz-v.size();
+                        for (uint8_t i=0; i<pad; ++i) {
+                            ans.push_back(0);
+                        }
+                        for (auto i=v.rbegin(); i!=v.rend(); ++i) {
+                            ans.push_back(*i);
+                        }
+                        if (neg) *ans.begin()|=0x80;
+                        stack.pop_back();
+                        stack.pop_back();
+                        stack.push_back(ans);
+                    } break;
+
                     default:
                         return set_error(serror, SCRIPT_ERR_BAD_OPCODE);
                 }
Index: src/script/script.h
===================================================================
--- src/script/script.h
+++ src/script/script.h
@@ -103,7 +103,6 @@
     // splice ops
     OP_CAT = 0x7e,
     OP_SPLIT = 0x7f,
-    OP_RIGHT = 0x81,
     OP_SIZE = 0x82,
 
     // bit logic
@@ -162,6 +161,7 @@
 
     // expansion
     OP_BIN2NUM = 0x80,
+    OP_NUM2BIN = 0x81,
     OP_NOP1 = 0xb0,
     OP_CHECKLOCKTIMEVERIFY = 0xb1,
     OP_NOP2 = OP_CHECKLOCKTIMEVERIFY,
Index: src/script/script.cpp
===================================================================
--- src/script/script.cpp
+++ src/script/script.cpp
@@ -123,8 +123,6 @@
             return "OP_CAT";
         case OP_SPLIT:
             return "OP_SPLIT";
-        case OP_RIGHT:
-            return "OP_RIGHT";
         case OP_SIZE:
             return "OP_SIZE";
 
Index: src/script/script_error.h
===================================================================
--- src/script/script_error.h
+++ src/script/script_error.h
@@ -38,6 +38,7 @@
     SCRIPT_ERR_MOD_BY_ZERO,
     SCRIPT_ERR_INVALID_SPLIT_RANGE,
     SCRIPT_ERR_INVALID_BIN2NUM_OPERATION,
+    SCRIPT_ERR_INVALID_NUM2BIN_OPERATION,
 
     /* CHECKLOCKTIMEVERIFY and CHECKSEQUENCEVERIFY */
     SCRIPT_ERR_NEGATIVE_LOCKTIME,
Index: src/script/script_error.cpp
===================================================================
--- src/script/script_error.cpp
+++ src/script/script_error.cpp
@@ -56,6 +56,8 @@
             return "Invalid OP_SPLIT range";
         case SCRIPT_ERR_INVALID_BIN2NUM_OPERATION:
             return "Invalid OP_BIN2NUM operation (check operand values)";
+        case SCRIPT_ERR_INVALID_NUM2BIN_OPERATION:
+            return "Invalid OP_NUM2BIN operation (check operand values)";
         case SCRIPT_ERR_NEGATIVE_LOCKTIME:
             return "Negative locktime";
         case SCRIPT_ERR_UNSATISFIED_LOCKTIME: