diff --git a/crypto/src/math/ec/rfc7748/X25519.cs b/crypto/src/math/ec/rfc7748/X25519.cs

index a10d53da5..d63cc5a3e 100644
--- a/crypto/src/math/ec/rfc7748/X25519.cs
+++ b/crypto/src/math/ec/rfc7748/X25519.cs
@@ -6,6 +6,9 @@ namespace Org.BouncyCastle.Math.EC.Rfc7748
 {
     public abstract class X25519
     {
+        public const int PointSize = 32;
+        public const int ScalarSize = 32;
+
         private const int C_A = 486662;
         private const int C_A24 = (C_A + 2)/4;
 
diff --git a/crypto/src/math/ec/rfc7748/X448.cs b/crypto/src/math/ec/rfc7748/X448.cs

index 88e8a5d76..aac603b08 100644
--- a/crypto/src/math/ec/rfc7748/X448.cs
+++ b/crypto/src/math/ec/rfc7748/X448.cs
@@ -6,6 +6,9 @@ namespace Org.BouncyCastle.Math.EC.Rfc7748
 {
     public abstract class X448
     {
+        public const int PointSize = 56;
+        public const int ScalarSize = 56;
+
         private const uint C_A = 156326;
         private const uint C_A24 = (C_A + 2)/4;