1 files changed, 28 insertions, 0 deletions
diff --git a/crypto/bn/bn_test.cc b/crypto/bn/bn_test.cc
index 3405cbdc..20f64d6c 100644
--- a/crypto/bn/bn_test.cc
+++ b/crypto/bn/bn_test.cc
@@ -584,6 +584,33 @@ static bool TestModSqrt(FileTest *t, BN_CTX *ctx) {
   return true;
 }
 
+static bool TestModInv(FileTest *t, BN_CTX *ctx) {
+  ScopedBIGNUM a = GetBIGNUM(t, "A");
+  ScopedBIGNUM m = GetBIGNUM(t, "M");
+  ScopedBIGNUM mod_inv = GetBIGNUM(t, "ModInv");
+  if (!a || !m || !mod_inv) {
+    return false;
+  }
+
+  ScopedBIGNUM ret(BN_new());
+  if (!ret ||
+      !BN_mod_inverse(ret.get(), a.get(), m.get(), ctx) ||
+      !ExpectBIGNUMsEqual(t, "inv(A) (mod M)", mod_inv.get(), ret.get())) {
+    return false;
+  }
+
+  BN_set_flags(a.get(), BN_FLG_CONSTTIME);
+
+  if (!ret ||
+      !BN_mod_inverse(ret.get(), a.get(), m.get(), ctx) ||
+      !ExpectBIGNUMsEqual(t, "inv(A) (mod M) (constant-time)", mod_inv.get(),
+                          ret.get())) {
+    return false;
+  }
+
+  return true;
+}
+
 struct Test {
   const char *name;
   bool (*func)(FileTest *t, BN_CTX *ctx);
@@ -601,6 +628,7 @@ static const Test kTests[] = {
     {"ModExp", TestModExp},
     {"Exp", TestExp},
     {"ModSqrt", TestModSqrt},
+    {"ModInv", TestModInv},
 };
 
 static bool RunTest(FileTest *t, void *arg) {