3 files changed, 76 insertions, 0 deletions
diff --git a/src/exhaustive/exhaustive.c b/src/exhaustive/exhaustive.c
index dbc1125..5ecac24 100644
--- a/src/exhaustive/exhaustive.c
+++ b/src/exhaustive/exhaustive.c
@@ -20,6 +20,7 @@
 #include "io/output.h"
 #include "misc/config.h"
 #include "obj/curve.h"
+#include "supersingular.h"
 #include "util/memory.h"
 #include "util/timeout.h"
 
@@ -124,6 +125,9 @@ static void exhaustive_ginit(gen_f *generators) {
 		if (cfg->method == METHOD_ANOMALOUS) {
 			generators[OFFSET_A] = &gen_skip;
 			generators[OFFSET_B] = &anomalous_gen_equation;
+		} else if (cfg->method == METHOD_SUPERSINGULAR) {
+			generators[OFFSET_A] = &gen_skip;
+			generators[OFFSET_B] = &supersingular_gen_equation;
 		} else if (cfg->koblitz) {
 			switch (cfg->koblitz_value) {
 				case 0:
diff --git a/src/exhaustive/supersingular.c b/src/exhaustive/supersingular.c
new file mode 100644
index 0000000..87e6786
--- /dev/null
+++ b/src/exhaustive/supersingular.c
@@ -0,0 +1,44 @@
+/*
+ * ecgen, tool for generating Elliptic curve domain parameters
+ * Copyright (C) 2017-2018 J08nY
+ */
+#include "supersingular.h"
+
+GENERATOR(supersingular_gen_equation) {
+	if (equalis(curve->field, 2)) {
+		return -2;
+	}
+	if (mod4(curve->field) == 3) {
+		curve->a = mkintmod(subis(curve->field, 1), curve->field);
+		curve->b = mkintmod(stoi(0), curve->field);
+		return 1;
+	}
+	GEN q = stoi(3);
+	while (mod4(q) != 3 && kronecker(curve->field, q) != -1) {
+		q = nextprime(q);
+	}
+
+	if (equalis(q, 3)) {
+		curve->a = mkintmod(stoi(0), curve->field);
+		curve->b = mkintmod(stoi(1), curve->field);
+		return 1;
+	} else {
+		GEN H = polclass(negi(q), 0, 0);
+		GEN r = FpX_roots(H, curve->field);
+		GEN root = gel(r, 1);
+		curve->a =
+		    Fp_div(Fp_mul(stoi(27), root, curve->field),
+		           Fp_mul(stoi(4), Fp_sub(stoi(1728), root, curve->field),
+		                  curve->field),
+		           curve->field);
+		curve->b = negi(curve->a);
+		return 1;
+	}
+}
+
+GENERATOR(supersingular_gen_order) {
+	// copy field to order
+	curve->order = addis(curve->field, 1);
+	obj_insert(curve->curve, 1, curve->order);
+	return 1;
+}
diff --git a/src/exhaustive/supersingular.h b/src/exhaustive/supersingular.h
new file mode 100644
index 0000000..bf7f267
--- /dev/null
+++ b/src/exhaustive/supersingular.h
@@ -0,0 +1,28 @@
+/*
+ * ecgen, tool for generating Elliptic curve domain parameters
+ * Copyright (C) 2017-2018 J08nY
+ */
+#ifndef ECGEN_EXHAUSTIVE_SUPERSINGULAR_H
+#define ECGEN_EXHAUSTIVE_SUPERSINGULAR_H
+
+#include "misc/types.h"
+
+/**
+ * @brief
+ * @param curve
+ * @param args
+ * @param state
+ * @return
+ */
+GENERATOR(supersingular_gen_equation);
+
+/**
+ * @brief
+ * @param curve
+ * @param args
+ * @param state
+ * @return
+ */
+GENERATOR(supersingular_gen_order);
+
+#endif  // ECGEN_EXHAUSTIVE_SUPERSINGULAR_H