diff --git a/src/crypto/crypto-ops.c b/src/crypto/crypto-ops.c
index dad60907..7553a1cb 100644
--- a/src/crypto/crypto-ops.c
+++ b/src/crypto/crypto-ops.c
@@ -332,7 +332,7 @@ static int fe_isnegative(const fe f) {
 
 /* From fe_isnonzero.c, modified */
 
-static int fe_isnonzero(const fe f) {
+int fe_isnonzero(const fe f) {
   unsigned char s[32];
   fe_tobytes(s, f);
   return (((int) (s[0] | s[1] | s[2] | s[3] | s[4] | s[5] | s[6] | s[7] | s[8] |
diff --git a/src/crypto/crypto-ops.h b/src/crypto/crypto-ops.h
index 07122772..e01735dd 100644
--- a/src/crypto/crypto-ops.h
+++ b/src/crypto/crypto-ops.h
@@ -128,6 +128,7 @@ int sc_isnonzero(const unsigned char *); /* Doesn't normalize */
 void sc_invert(unsigned char*, const unsigned char*);
 
 void fe_sq(fe h, const fe f);
+int fe_isnonzero(const fe f);
 void fe_mul(fe, const fe, const fe);
 void fe_frombytes(fe h, const unsigned char *s);
 void fe_invert(fe out, const fe z);
diff --git a/tests/functional_tests/crypto_tests.cpp b/tests/functional_tests/crypto_tests.cpp
index 4ba6717d..3b7aec3e 100644
--- a/tests/functional_tests/crypto_tests.cpp
+++ b/tests/functional_tests/crypto_tests.cpp
@@ -418,6 +418,12 @@ struct point_t
     ge_p3_0(&m_p3);
   }
 
+  bool is_zero() const
+  {
+    // (0, 1) ~ (0, z, z, 0)
+    return fe_isnonzero(m_p3.X) * fe_cmp(m_p3.Y, m_p3.Z) == 0;
+  }
+
   bool from_public_key(const crypto::public_key& pk)
   {
     return ge_frombytes_vartime(&m_p3, reinterpret_cast<const unsigned char*>(&pk)) == 0;