Add circom-examples/equation.circom

circom-examples/circuits/equation.circom

@@ -0,0 +1,35 @@
+include "../node_modules/circomlib/circuits/comparators.circom";
+
+/*
+	Circuit to check that prover knows a private inputs x & y,
+	such as x**a - y**b = 0, where a & b are known parameters.
+*/
+template Equation(a, b) {
+	signal private input x;
+	signal private input y;
+
+	
+	signal aArray[a];
+	signal bArray[b];
+	for (var i=0; i<a; i++) {
+		if (i==0) {
+			aArray[0] <== x;
+		} else {
+			aArray[i] <== x * aArray[i-1];
+		}
+	}
+	for(var i=0; i<b; i++) {
+		if (i==0) {
+			bArray[0] <== y;
+		} else {
+			bArray[i] <== y * bArray[i-1];
+		}
+	}
+	
+	component checkEq = IsEqual();
+	checkEq.in[0] <== aArray[a-1];
+	checkEq.in[1] <== bArray[b-1];
+	checkEq.out === 1;
+}
+
+component main = Equation(4, 8);