diff --git a/crypto/fipsmodule/ec/ec.c b/crypto/fipsmodule/ec/ec.c
index 2195d06..04f2a98 100644
--- a/crypto/fipsmodule/ec/ec.c
+++ b/crypto/fipsmodule/ec/ec.c
@@ -1074,8 +1074,10 @@
   group->meth->mul_base(group, r, scalar);
 
   // Check the result is on the curve to defend against fault attacks or bugs.
-  // This has negligible cost compared to the multiplication.
-  if (!ec_GFp_simple_is_on_curve(group, r)) {
+  // This has negligible cost compared to the multiplication. This can only
+  // happen on bug or CPU fault, so it okay to leak this. The alternative would
+  // be to proceed with bad data.
+  if (!constant_time_declassify_int(ec_GFp_simple_is_on_curve(group, r))) {
     OPENSSL_PUT_ERROR(EC, ERR_R_INTERNAL_ERROR);
     return 0;
   }
diff --git a/crypto/fipsmodule/ec/ec_montgomery.c b/crypto/fipsmodule/ec/ec_montgomery.c
index eeaee64..78e0507 100644
--- a/crypto/fipsmodule/ec/ec_montgomery.c
+++ b/crypto/fipsmodule/ec/ec_montgomery.c
@@ -177,7 +177,8 @@
 static int ec_GFp_mont_point_get_affine_coordinates(const EC_GROUP *group,
                                                     const EC_JACOBIAN *point,
                                                     EC_FELEM *x, EC_FELEM *y) {
-  if (ec_GFp_simple_is_at_infinity(group, point)) {
+  if (constant_time_declassify_int(
+          ec_GFp_simple_is_at_infinity(group, point))) {
     OPENSSL_PUT_ERROR(EC, EC_R_POINT_AT_INFINITY);
     return 0;
   }
@@ -317,7 +318,7 @@
 
   // This case will never occur in the constant-time |ec_GFp_mont_mul|.
   BN_ULONG is_nontrivial_double = ~xneq & ~yneq & z1nz & z2nz;
-  if (is_nontrivial_double) {
+  if (constant_time_declassify_w(is_nontrivial_double)) {
     ec_GFp_mont_dbl(group, out, a);
     return;
   }
diff --git a/crypto/fipsmodule/ec/internal.h b/crypto/fipsmodule/ec/internal.h
index 8532026..bb41815 100644
--- a/crypto/fipsmodule/ec/internal.h
+++ b/crypto/fipsmodule/ec/internal.h
@@ -479,7 +479,8 @@
 
   // point_get_affine_coordinates sets |*x| and |*y| to the affine coordinates
   // of |p|. Either |x| or |y| may be NULL to omit it. It returns one on success
-  // and zero if |p| is the point at infinity.
+  // and zero if |p| is the point at infinity. It leaks whether |p| was the
+  // point at infinity, but otherwise treats |p| as secret.
   int (*point_get_affine_coordinates)(const EC_GROUP *, const EC_JACOBIAN *p,
                                       EC_FELEM *x, EC_FELEM *y);
 
diff --git a/crypto/fipsmodule/ec/p224-64.c b/crypto/fipsmodule/ec/p224-64.c
index ef83b29..b646e82 100644
--- a/crypto/fipsmodule/ec/p224-64.c
+++ b/crypto/fipsmodule/ec/p224-64.c
@@ -734,8 +734,8 @@
   // tmp[i] < 2^116 + 2^64 + 8 < 2^117
   p224_felem_reduce(ftmp, tmp);
 
-  // the formulae are incorrect if the points are equal
-  // so we check for this and do doubling if this happens
+  // The formulae are incorrect if the points are equal, so we check for this
+  // and do doubling if this happens.
   x_equal = p224_felem_is_zero(ftmp);
   y_equal = p224_felem_is_zero(ftmp3);
   z1_is_zero = p224_felem_is_zero(z1);
@@ -743,7 +743,7 @@
   // In affine coordinates, (X_1, Y_1) == (X_2, Y_2)
   p224_limb is_nontrivial_double =
       x_equal & y_equal & (1 - z1_is_zero) & (1 - z2_is_zero);
-  if (is_nontrivial_double) {
+  if (constant_time_declassify_w(is_nontrivial_double)) {
     p224_point_double(x3, y3, z3, x1, y1, z1);
     return;
   }
@@ -862,7 +862,8 @@
 static int ec_GFp_nistp224_point_get_affine_coordinates(
     const EC_GROUP *group, const EC_JACOBIAN *point, EC_FELEM *x,
     EC_FELEM *y) {
-  if (ec_GFp_simple_is_at_infinity(group, point)) {
+  if (constant_time_declassify_int(
+          ec_GFp_simple_is_at_infinity(group, point))) {
     OPENSSL_PUT_ERROR(EC, EC_R_POINT_AT_INFINITY);
     return 0;
   }
diff --git a/crypto/fipsmodule/ec/p256-nistz.c b/crypto/fipsmodule/ec/p256-nistz.c
index dfde2f4..85343fd 100644
--- a/crypto/fipsmodule/ec/p256-nistz.c
+++ b/crypto/fipsmodule/ec/p256-nistz.c
@@ -422,7 +422,8 @@
 static int ecp_nistz256_get_affine(const EC_GROUP *group,
                                    const EC_JACOBIAN *point, EC_FELEM *x,
                                    EC_FELEM *y) {
-  if (ec_GFp_simple_is_at_infinity(group, point)) {
+  if (constant_time_declassify_int(
+          ec_GFp_simple_is_at_infinity(group, point))) {
     OPENSSL_PUT_ERROR(EC, EC_R_POINT_AT_INFINITY);
     return 0;
   }
diff --git a/crypto/fipsmodule/ec/p256.c b/crypto/fipsmodule/ec/p256.c
index af211be..76e865f 100644
--- a/crypto/fipsmodule/ec/p256.c
+++ b/crypto/fipsmodule/ec/p256.c
@@ -324,7 +324,7 @@
   fiat_p256_limb_t is_nontrivial_double = constant_time_is_zero_w(xneq | yneq) &
                                           ~constant_time_is_zero_w(z1nz) &
                                           ~constant_time_is_zero_w(z2nz);
-  if (is_nontrivial_double) {
+  if (constant_time_declassify_w(is_nontrivial_double)) {
     fiat_p256_point_double(x3, y3, z3, x1, y1, z1);
     return;
   }
@@ -416,7 +416,8 @@
 static int ec_GFp_nistp256_point_get_affine_coordinates(
     const EC_GROUP *group, const EC_JACOBIAN *point, EC_FELEM *x_out,
     EC_FELEM *y_out) {
-  if (ec_GFp_simple_is_at_infinity(group, point)) {
+  if (constant_time_declassify_int(
+          ec_GFp_simple_is_at_infinity(group, point))) {
     OPENSSL_PUT_ERROR(EC, EC_R_POINT_AT_INFINITY);
     return 0;
   }
diff --git a/crypto/fipsmodule/ecdsa/ecdsa.c b/crypto/fipsmodule/ecdsa/ecdsa.c
index be19540..1be147f 100644
--- a/crypto/fipsmodule/ecdsa/ecdsa.c
+++ b/crypto/fipsmodule/ecdsa/ecdsa.c
@@ -223,7 +223,7 @@
     return NULL;
   }
 
-  if (ec_scalar_is_zero(group, &r)) {
+  if (constant_time_declassify_int(ec_scalar_is_zero(group, &r))) {
     *out_retry = 1;
     return NULL;
   }
@@ -250,11 +250,13 @@
   ec_scalar_inv0_montgomery(group, &tmp, k);     // tmp = k^-1 R^2
   ec_scalar_from_montgomery(group, &tmp, &tmp);  // tmp = k^-1 R
   ec_scalar_mul_montgomery(group, &s, &s, &tmp);
-  if (ec_scalar_is_zero(group, &s)) {
+  if (constant_time_declassify_int(ec_scalar_is_zero(group, &s))) {
     *out_retry = 1;
     return NULL;
   }
 
+  CONSTTIME_DECLASSIFY(r.words, sizeof(r.words));
+  CONSTTIME_DECLASSIFY(s.words, sizeof(r.words));
   ECDSA_SIG *ret = ECDSA_SIG_new();
   if (ret == NULL ||  //
       !bn_set_words(ret->r, r.words, order->width) ||
@@ -347,6 +349,10 @@
       goto out;
     }
 
+    // TODO(davidben): Move this inside |ec_random_nonzero_scalar| or lower, so
+    // that all scalars we generate are, by default, secret.
+    CONSTTIME_SECRET(k.words, sizeof(k.words));
+
     int retry;
     ret = ecdsa_sign_impl(group, &retry, priv_key, &k, digest, digest_len);
     if (ret != NULL || !retry) {