Implement static method for creating a randomized JSDescription

src/primitives/transaction.cpp

@@ -6,6 +6,7 @@
 #include "primitives/transaction.h"
 
 #include "hash.h"
+#include "random.h"
 #include "tinyformat.h"
 #include "utilstrencodings.h"
 
@@ -41,6 +42,29 @@ JSDescription::JSDescription(ZCJoinSplit& params,
     );
 }
 
+JSDescription JSDescription::Randomized(
+            ZCJoinSplit& params,
+            const uint256& pubKeyHash,
+            const uint256& anchor,
+            boost::array<libzcash::JSInput, ZC_NUM_JS_INPUTS>& inputs,
+            boost::array<libzcash::JSOutput, ZC_NUM_JS_OUTPUTS>& outputs,
+            boost::array<size_t, ZC_NUM_JS_INPUTS>& inputMap,
+            boost::array<size_t, ZC_NUM_JS_OUTPUTS>& outputMap,
+            CAmount vpub_old,
+            CAmount vpub_new,
+            bool computeProof)
+{
+    // Randomize the order of the inputs and outputs
+    inputMap = {0, 1};
+    outputMap = {0, 1};
+    MappedShuffle(inputs.begin(), inputMap.begin(), ZC_NUM_JS_INPUTS, GetRandInt);
+    MappedShuffle(outputs.begin(), outputMap.begin(), ZC_NUM_JS_OUTPUTS, GetRandInt);
+
+    return JSDescription(
+        params, pubKeyHash, anchor, inputs, outputs,
+        vpub_old, vpub_new, computeProof);
+}
+
 bool JSDescription::Verify(
     ZCJoinSplit& params,
     const uint256& pubKeyHash