diff --git a/Libraries/Opc.Ua.Security.Certificates/Org.BouncyCastle/PEMReader.cs b/Libraries/Opc.Ua.Security.Certificates/Org.BouncyCastle/PEMReader.cs
index 17249e2c8..2d2666947 100644
--- a/Libraries/Opc.Ua.Security.Certificates/Org.BouncyCastle/PEMReader.cs
+++ b/Libraries/Opc.Ua.Security.Certificates/Org.BouncyCastle/PEMReader.cs
@@ -35,6 +35,7 @@
 using Org.BouncyCastle.OpenSsl;
 using Org.BouncyCastle.Security;
 using Org.BouncyCastle.Crypto.Parameters;
+using Opc.Ua.Security.Certificates.BouncyCastle;
 
 namespace Opc.Ua.Security.Certificates
 {
@@ -168,9 +169,9 @@ private static ECDsa CreateECDsaFromECPrivateKey(ECPrivateKeyParameters eCPrivat
             var d = eCPrivateKeyParameters.D.ToByteArrayUnsigned();
 
             // pad all to the same length since ToByteArrayUnsigned might drop leading zeroes
-            x = PadWithLeadingZeros(x, keySizeBytes);
-            y = PadWithLeadingZeros(y, keySizeBytes);
-            d = PadWithLeadingZeros(d, keySizeBytes);
+            x = X509Utils.PadWithLeadingZeros(x, keySizeBytes);
+            y = X509Utils.PadWithLeadingZeros(y, keySizeBytes);
+            d = X509Utils.PadWithLeadingZeros(d, keySizeBytes);
 
 
             var ecParams = new ECParameters {
@@ -190,34 +191,6 @@ private static ECDsa CreateECDsaFromECPrivateKey(ECPrivateKeyParameters eCPrivat
         }
 #endif
 
-        /// <summary>
-        /// Pads a byte array with leading zeros to reach the specifieed size
-        /// If the input is allready the given size, it just returns it
-        /// </summary>
-        /// <param name="arrayToPad">Provided array to pad</param>
-        /// <param name="desiredSize">The desired total length of byte array after padding</param>
-        /// <returns></returns>
-        private static byte[] PadWithLeadingZeros(byte[] arrayToPad,  int desiredSize)
-        {
-            if (arrayToPad.Length == desiredSize)
-            {
-                return arrayToPad;
-            }
-
-            int paddingLength = desiredSize - arrayToPad.Length;
-            if (paddingLength < 0)
-            {
-                throw new ArgumentException($"Input byte array is larger than the desired size {desiredSize} bytes.");
-            }
-
-            var paddedArray = new byte[desiredSize];
-
-            // Right-align the arrayToPad into paddedArray
-            Buffer.BlockCopy(arrayToPad, 0, paddedArray, paddingLength, arrayToPad.Length);
-
-            return paddedArray;
-
-        }
 #endregion
 
         #region Internal class
diff --git a/Libraries/Opc.Ua.Security.Certificates/Org.BouncyCastle/X509Utils.cs b/Libraries/Opc.Ua.Security.Certificates/Org.BouncyCastle/X509Utils.cs
index f125728a2..ca17f0833 100644
--- a/Libraries/Opc.Ua.Security.Certificates/Org.BouncyCastle/X509Utils.cs
+++ b/Libraries/Opc.Ua.Security.Certificates/Org.BouncyCastle/X509Utils.cs
@@ -370,6 +370,35 @@ internal static RSA SetRSAPublicKey(byte[] publicKey)
             rsaPublicKey.ImportParameters(parameters);
             return rsaPublicKey;
         }
+
+        /// <summary>
+        /// Pads a byte array with leading zeros to reach the specifieed size
+        /// If the input is allready the given size, it just returns it
+        /// </summary>
+        /// <param name="arrayToPad">Provided array to pad</param>
+        /// <param name="desiredSize">The desired total length of byte array after padding</param>
+        /// <returns></returns>
+        internal static byte[] PadWithLeadingZeros(byte[] arrayToPad,  int desiredSize)
+        {
+            if (arrayToPad.Length == desiredSize)
+            {
+                return arrayToPad;
+            }
+
+            int paddingLength = desiredSize - arrayToPad.Length;
+            if (paddingLength < 0)
+            {
+                throw new ArgumentException($"Input byte array is larger than the desired size {desiredSize} bytes.");
+            }
+
+            var paddedArray = new byte[desiredSize];
+
+            // Right-align the arrayToPad into paddedArray
+            Buffer.BlockCopy(arrayToPad, 0, paddedArray, paddingLength, arrayToPad.Length);
+
+            return paddedArray;
+
+        }
 #endregion
     }
 }
diff --git a/Libraries/Opc.Ua.Security.Certificates/X509Certificate/CertificateBuilder.cs b/Libraries/Opc.Ua.Security.Certificates/X509Certificate/CertificateBuilder.cs
index de8480f04..fe4e49861 100644
--- a/Libraries/Opc.Ua.Security.Certificates/X509Certificate/CertificateBuilder.cs
+++ b/Libraries/Opc.Ua.Security.Certificates/X509Certificate/CertificateBuilder.cs
@@ -42,6 +42,7 @@
 using Org.BouncyCastle.Asn1.X509;
 using Org.BouncyCastle.Asn1.X9;
 using Org.BouncyCastle.Math.EC;
+using Opc.Ua.Security.Certificates.BouncyCastle;
 #endif
 
 namespace Opc.Ua.Security.Certificates
@@ -297,35 +298,36 @@ public override ICertificateBuilderCreateForECDsaAny SetECDsaPublicKey(byte[] pu
                 var publicKeyInfo = SubjectPublicKeyInfo.GetInstance(asn1Obj);
                 var algParams = publicKeyInfo.Algorithm.Parameters;
                 var x962Params = X962Parameters.GetInstance(algParams);
-                var ecPoint = publicKeyInfo.PublicKey.GetBytes();
                     
                 ECParameters ecParameters = new ECParameters();
-                X9ECParameters ecParametersAsn1 = null;
+
+                var domainParameters = asymmetricPubKeyParameters.Parameters;
+                var q = asymmetricPubKeyParameters.Q;
+                // calculate keySize round up (bitLength + 7) / 8
+                int keySizeBytes = (domainParameters.N.BitLength + 7) / 8;
 
                 if (x962Params.IsNamedCurve)
                 {
                     // Named
                     var namedCurveOid = (DerObjectIdentifier)x962Params.Parameters;
                     string curveName = namedCurveOid.Id;
-
                     var ecCurve = System.Security.Cryptography.ECCurve.CreateFromOid(new Oid(curveName));
                     ecParameters.Curve = ecCurve;
                 }
                 else
                 {
-                    // Explicit but still need to create the curve as named since the platform does not support it's creation
-                    // otherwise
-                    ecParametersAsn1 = X9ECParameters.GetInstance(x962Params.Parameters);
-                    ecParameters.Curve = BouncyCastle.X509Utils.IdentifyEccCurveByCoefficients(ecParametersAsn1.Curve.A.GetEncoded(),
-                        ecParametersAsn1.Curve.B.GetEncoded());// instead of ecParametersAsn1.Curve;
-
+                    // Explicit parameters
+                    var a = X509Utils.PadWithLeadingZeros(domainParameters.Curve.A.ToBigInteger().ToByteArrayUnsigned(), keySizeBytes);
+                    var b = X509Utils.PadWithLeadingZeros(domainParameters.Curve.B.ToBigInteger().ToByteArrayUnsigned(), keySizeBytes);
+                    ecParameters.Curve = BouncyCastle.X509Utils.IdentifyEccCurveByCoefficients(a,b);
                 }
 
-                //Extract the public key coordinates
-                var publicKeyPoint = new X9ECPoint(ecParametersAsn1.Curve, ecPoint).Point;
+                var x = X509Utils.PadWithLeadingZeros(q.AffineXCoord.ToBigInteger().ToByteArrayUnsigned(), keySizeBytes);
+                var y = X509Utils.PadWithLeadingZeros(q.AffineYCoord.ToBigInteger().ToByteArrayUnsigned(), keySizeBytes);
+                // Use the Q point
                 ecParameters.Q = new System.Security.Cryptography.ECPoint {
-                    X = publicKeyPoint.AffineXCoord.ToBigInteger().ToByteArrayUnsigned(),
-                    Y = publicKeyPoint.AffineYCoord?.ToBigInteger().ToByteArrayUnsigned()
+                    X = x,
+                    Y = y
                 };
 
                 m_ecdsaPublicKey.ImportParameters(ecParameters);
@@ -334,6 +336,7 @@ public override ICertificateBuilderCreateForECDsaAny SetECDsaPublicKey(byte[] pu
 #else
                 m_ecdsaPublicKey.ImportSubjectPublicKeyInfo(publicKey, out bytes);
 #endif
+                SetECCurve(m_ecdsaPublicKey.ExportParameters(false).Curve);
             }
             catch (Exception e)
             {