Index: src/script/interpreter.cpp
===================================================================
--- src/script/interpreter.cpp
+++ src/script/interpreter.cpp
@@ -797,18 +797,21 @@
 
                         switch (opcode) {
                             case OP_AND:
-                                for (size_t i = 0; i < vch1.size(); i++) {
-                                    vch1[i] &= vch2[i];
+                                for (auto it = vch1.begin(); it != vch1.end(); ++it) {
+                                    auto i = std::distance(vch1.begin(), it);
+                                    *it &= vch2[i];
                                 }
                                 break;
                             case OP_OR:
-                                for (size_t i = 0; i < vch1.size(); i++) {
-                                    vch1[i] |= vch2[i];
+                                for (auto it = vch1.begin(); it != vch1.end(); ++it) {
+                                    auto i = std::distance(vch1.begin(), it);
+                                    *it |= vch2[i];
                                 }
                                 break;
                             case OP_XOR:
-                                for (size_t i = 0; i < vch1.size(); i++) {
-                                    vch1[i] ^= vch2[i];
+                                for (auto it = vch1.begin(); it != vch1.end(); ++it) {
+                                    auto i = std::distance(vch1.begin(), it);
+                                    *it ^= vch2[i];
                                 }
                                 break;
                         }