out of bounds on constraint gen maybe 2d array?

circom/templates/chaff.circom

@@ -0,0 +1,50 @@
+pragma circom 2.1.6;
+
+include "../node_modules/circomlib/circuits/mux1.circom";
+include "../node_modules/circomlib/circuits/comparators.circom";
+
+// multiplexes signals according to whether this is a chaff step or not
+template ChaffMux() {
+    // inputs from step_in
+    signal input degrees_of_separation;
+    signal input given_phrase_hash;
+    signal input given_degree_secret_hash;
+    signal input is_chaff_step;
+    // computed inputs from circuit
+    signal input computed_phrase_hash;
+    signal input computed_degree_secret_hash;
+    // output formatted for step_out
+    signal output out[4];
+
+    // constrain is_chaff_step to be 0 or 1
+    is_chaff_step * (is_chaff_step - 1) === 0;
+
+    // mux 3 different inputs selected by is_chaff_step
+    component mux = MultiMux1(3);
+    mux.s <== is_chaff_step;
+
+    // mux the degree of separation
+    // if ! chaff step, increment degree of separation
+    mux.c[0][0] <== degrees_of_separation + 1;
+    mux.c[0][1] <== degrees_of_separation;
+
+    // mux the secret hash
+    // if ! chaff step, grab muxed hash output
+    mux.c[1][0] <== computed_phrase_hash;
+    mux.c[1][1] <== given_phrase_hash;
+
+    // mux the username hash
+    // if ! chaff step, grab the computed current username hash
+    mux.c[2][0] <== computed_degree_secret_hash;
+    mux.c[2][1] <== given_degree_secret_hash;
+
+    // flip chaff step
+    component flipped_chaff_step = IsZero();
+    flipped_chaff_step.in <== is_chaff_step;
+
+    // set step output
+    out[0] <== mux.out[0];
+    out[1] <== mux.out[1];
+    out[2] <== mux.out[2];
+    out[3] <== flipped_chaff_step.out;
+}