diff --git a/src/script/script.h b/src/script/script.h
--- a/src/script/script.h
+++ b/src/script/script.h
@@ -182,6 +182,9 @@
     OP_CHECKDATASIG = 0xba,
     OP_CHECKDATASIGVERIFY = 0xbb,
 
+    // additional byte string operations
+    OP_BSWAP = 0xbc,
+
     // The first op_code value after all defined opcodes
     FIRST_UNDEFINED_OP_VALUE,
 
diff --git a/src/script/script.cpp b/src/script/script.cpp
--- a/src/script/script.cpp
+++ b/src/script/script.cpp
@@ -232,6 +232,8 @@
             return "OP_CHECKDATASIG";
         case OP_CHECKDATASIGVERIFY:
             return "OP_CHECKDATASIGVERIFY";
+        case OP_BSWAP:
+            return "OP_BSWAP";
 
         // expansion
         case OP_NOP1:
diff --git a/test/functional/test_framework/script.py b/test/functional/test_framework/script.py
--- a/test/functional/test_framework/script.py
+++ b/test/functional/test_framework/script.py
@@ -242,6 +242,9 @@
 OP_CHECKDATASIG = CScriptOp(0xba)
 OP_CHECKDATASIGVERIFY = CScriptOp(0xbb)
 
+# additional byte string operations
+OP_BSWAP = CScriptOp(0xc0)
+
 # multi-byte opcodes
 OP_PREFIX_BEGIN = CScriptOp(0xf0)
 OP_PREFIX_END = CScriptOp(0xf7)