1 files changed, 22 insertions, 33 deletions

diff --git a/crypto/src/asn1/esf/SignaturePolicyIdentifier.cs b/crypto/src/asn1/esf/SignaturePolicyIdentifier.cs
index 12257f2f0..eb6c0654c 100644
--- a/crypto/src/asn1/esf/SignaturePolicyIdentifier.cs
+++ b/crypto/src/asn1/esf/SignaturePolicyIdentifier.cs
@@ -17,50 +17,39 @@ namespace Org.BouncyCastle.Asn1.Esf
 	public class SignaturePolicyIdentifier
 		: Asn1Encodable, IAsn1Choice
 	{
-		private readonly SignaturePolicyId sigPolicy;
-
-		public static SignaturePolicyIdentifier GetInstance(
-			object obj)
+		public static SignaturePolicyIdentifier GetInstance(object obj)
 		{
-			if (obj == null || obj is SignaturePolicyIdentifier)
-				return (SignaturePolicyIdentifier) obj;
+			if (obj == null)
+				return null;
 
-			if (obj is SignaturePolicyId)
-				return new SignaturePolicyIdentifier((SignaturePolicyId) obj);
+			if (obj is SignaturePolicyIdentifier signaturePolicyIdentifier)
+				return signaturePolicyIdentifier;
 
-			if (obj is Asn1Null)
-				return new SignaturePolicyIdentifier();
+            if (obj is Asn1Null)
+                return new SignaturePolicyIdentifier();
 
-			throw new ArgumentException(
-				"Unknown object in 'SignaturePolicyIdentifier' factory: "
-                    + Platform.GetTypeName(obj),
-				"obj");
+			return new SignaturePolicyIdentifier(SignaturePolicyId.GetInstance(obj));
 		}
 
-		public SignaturePolicyIdentifier()
-		{
-			this.sigPolicy = null;
-		}
+        public static SignaturePolicyIdentifier GetInstance(Asn1TaggedObject taggedObject, bool declaredExplicit)
+        {
+            return Asn1Utilities.GetInstanceFromChoice(taggedObject, declaredExplicit, GetInstance);
+        }
 
-		public SignaturePolicyIdentifier(
-			SignaturePolicyId signaturePolicyId)
-		{
-			if (signaturePolicyId == null)
-				throw new ArgumentNullException("signaturePolicyId");
+        private readonly SignaturePolicyId m_sigPolicy;
 
-			this.sigPolicy = signaturePolicyId;
-		}
-
-		public SignaturePolicyId SignaturePolicyId
+        public SignaturePolicyIdentifier()
 		{
-			get { return sigPolicy; }
+			m_sigPolicy = null;
 		}
 
-		public override Asn1Object ToAsn1Object()
+		public SignaturePolicyIdentifier(SignaturePolicyId signaturePolicyId)
 		{
-			return sigPolicy == null
-				?	DerNull.Instance
-				:	sigPolicy.ToAsn1Object();
-		}
+			m_sigPolicy = signaturePolicyId ?? throw new ArgumentNullException(nameof(signaturePolicyId));
+        }
+
+        public SignaturePolicyId SignaturePolicyId => m_sigPolicy;
+
+		public override Asn1Object ToAsn1Object() => m_sigPolicy?.ToAsn1Object() ?? DerNull.Instance;
 	}
 }