Imported Upstream version 5.18.0.142

Former-commit-id: 7467d4b717762eeaf652d77f1486dd11ffb1ff1f

mcs/class/System.Core/System.Security.Cryptography.X509Certificates/DSACertificateExtensions.cs

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+//
+// DSACertificateExtensions.cs
+//
+// Authors:
+//	Filip Navara <filip.navara@gmail.com>
+//
+// Copyright (C) 2018 .NET Foundation and Contributors
+//
+// Permission is hereby granted, free of charge, to any person obtaining
+// a copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to
+// permit persons to whom the Software is furnished to do so, subject to
+// the following conditions:
+//
+// The above copyright notice and this permission notice shall be
+// included in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+//
+
+namespace System.Security.Cryptography.X509Certificates
+{
+	public static class DSACertificateExtensions
+	{
+		/// <summary>
+		/// Gets the <see cref="DSA" /> public key from the certificate or null if the certificate does not have a DSA public key.
+		/// </summary>
+		public static DSA GetDSAPublicKey(this X509Certificate2 certificate)
+		{
+			if (certificate == null)
+				throw new ArgumentNullException("certificate");
+			return certificate.PrivateKey as DSA;
+		}
+
+		/// <summary>
+		/// Gets the <see cref="DSA" /> private key from the certificate or null if the certificate does not have a DSA private key.
+		/// </summary>
+		public static DSA GetDSAPrivateKey(this X509Certificate2 certificate)
+		{
+			if (certificate == null)
+				throw new ArgumentNullException("certificate");
+			return certificate.PublicKey.Key as DSA;
+		}
+
+		[MonoTODO]
+		public static X509Certificate2 CopyWithPrivateKey(this X509Certificate2 certificate, DSA privateKey)
+		{
+			if (certificate == null)
+				throw new ArgumentNullException(nameof(certificate));
+			if (privateKey == null)
+				throw new ArgumentNullException(nameof(privateKey));
+
+			throw new NotImplementedException ();
+		}
+	}
+}