ECDH key import

ecdh.cs

    var clientKey = CreateEcDiffieHellmanPublicKey("MHYwEAYHKoZIzj0CAQYFK4EEACIDYgAEDEKneqEvcqUqqFMM1HM1A4zWjJC+I8Y+aKzG5dl+6wNOHHQ4NmG2PEXRJYhujyodFH+wO0dEr4GM1WoaWog8xsYQ6mQJAC0eVpBM96spUB1eMN56+BwlJ4H3Qx4TAvAs");

		private ECDiffieHellmanPublicKey CreateEcDiffieHellmanPublicKey(string clientPubKeyString)
		{
			byte[] clientPublicKeyBlob = Base64Url.Decode(clientPubKeyString);
			clientPublicKeyBlob = FixPublicKey(clientPublicKeyBlob.Skip(23).ToArray());

			ECDiffieHellmanPublicKey clientKey = ECDiffieHellmanCngPublicKey.FromByteArray(clientPublicKeyBlob, CngKeyBlobFormat.EccPublicBlob);
			return clientKey;
		}

		private byte[] FixPublicKey(byte[] publicKeyBlob)
		{
			var keyType = new byte[] { 0x45, 0x43, 0x4b, 0x33 };
			var keyLength = new byte[] { 0x30, 0x00, 0x00, 0x00 };

			return keyType.Concat(keyLength).Concat(publicKeyBlob.Skip(1)).ToArray();
		}

export.xml

<ECDHKeyValue xmlns="http://www.w3.org/2001/04/xmldsig-more#">
  <DomainParameters>
    <NamedCurve URN="urn:oid:1.3.132.0.34" />
  </DomainParameters>
  <PublicKey>
    <X Value="1887043347549410128067565566542224816143452851761995862716407003225384875968035424168426761708290432619967335574045" xsi:type="PrimeFieldElemType" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" />
    <Y Value="3155051437858668033874279868728733492162411352943682858660003704694667689155247425242901825513751062462637183004716" xsi:type="PrimeFieldElemType" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" />
  </PublicKey>
</ECDHKeyValue>