Add ec point validation functions

jiegec · Feb 15, 2021 · 687f0d2 · 687f0d2
1 parent 71b6e3f
commit 687f0d2
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diff --git a/openssl-sys/src/ec.rs b/openssl-sys/src/ec.rs
@@ -81,6 +81,14 @@ extern "C" {
 
     pub fn EC_GROUP_new_by_curve_name(nid: c_int) -> *mut EC_GROUP;
 
+    pub fn EC_POINT_is_at_infinity(group: *const EC_GROUP, point: *const EC_POINT) -> c_int;
+
+    pub fn EC_POINT_is_on_curve(
+        group: *const EC_GROUP,
+        point: *const EC_POINT,
+        ctx: *mut BN_CTX,
+    ) -> c_int;
+
     pub fn EC_POINT_new(group: *const EC_GROUP) -> *mut EC_POINT;
 
     pub fn EC_POINT_free(point: *mut EC_POINT);

diff --git a/openssl/src/ec.rs b/openssl/src/ec.rs
@@ -527,6 +527,30 @@ impl EcPointRef {
             .map(|_| ())
         }
     }
+
+    /// Checks if point is infinity
+    pub fn is_infinity(&self, group: &EcGroupRef) -> Result<bool, ErrorStack> {
+        unsafe {
+            let res = cvt_n(ffi::EC_POINT_is_at_infinity(group.as_ptr(), self.as_ptr()))?;
+            Ok(res == 1)
+        }
+    }
+
+    /// Checks if point is on a given curve
+    pub fn is_on_curve(
+        &self,
+        group: &EcGroupRef,
+        ctx: &mut BigNumContextRef,
+    ) -> Result<bool, ErrorStack> {
+        unsafe {
+            let res = cvt_n(ffi::EC_POINT_is_on_curve(
+                group.as_ptr(),
+                self.as_ptr(),
+                ctx.as_ptr(),
+            ))?;
+            Ok(res == 1)
+        }
+    }
 }
 
 impl EcPoint {
@@ -1074,4 +1098,29 @@ mod test {
         assert_eq!(xbn2, xbn);
         assert_eq!(ybn2, ybn);
     }
+
+    #[test]
+    fn is_infinity() {
+        let group = EcGroup::from_curve_name(Nid::X9_62_PRIME256V1).unwrap();
+        let mut ctx = BigNumContext::new().unwrap();
+        let g = group.generator();
+        assert_eq!(g.is_infinity(&group).unwrap(), false);
+
+        let mut order = BigNum::new().unwrap();
+        group.order(&mut order, &mut ctx).unwrap();
+        let mut inf = EcPoint::new(&group).unwrap();
+        inf.mul_generator(&group, &order, &ctx).unwrap();
+        assert_eq!(inf.is_infinity(&group).unwrap(), true);
+    }
+
+    #[test]
+    fn is_on_curve() {
+        let group = EcGroup::from_curve_name(Nid::X9_62_PRIME256V1).unwrap();
+        let mut ctx = BigNumContext::new().unwrap();
+        let g = group.generator();
+        assert_eq!(g.is_on_curve(&group, &mut ctx).unwrap(), true);
+
+        let group2 = EcGroup::from_curve_name(Nid::X9_62_PRIME239V3).unwrap();
+        assert_eq!(g.is_on_curve(&group2, &mut ctx).unwrap(), false);
+    }
 }