Refactoring in Asn1

30 files changed, 559 insertions, 742 deletions

diff --git a/crypto/src/asn1/ASN1StreamParser.cs b/crypto/src/asn1/ASN1StreamParser.cs
index 490b20ccf..85b890a8c 100644
--- a/crypto/src/asn1/ASN1StreamParser.cs
+++ b/crypto/src/asn1/ASN1StreamParser.cs
@@ -205,7 +205,7 @@ namespace Org.BouncyCastle.Asn1
         internal Asn1TaggedObjectParser ParseTaggedObject()
         {
             int tagHdr = _in.ReadByte();
-            if (tagHdr< 0)
+            if (tagHdr < 0)
                 return null;
 
             int tagClass = tagHdr & Asn1Tags.Private;
diff --git a/crypto/src/asn1/Asn1OutputStream.cs b/crypto/src/asn1/Asn1OutputStream.cs
index 163e3848c..1363aa676 100644
--- a/crypto/src/asn1/Asn1OutputStream.cs
+++ b/crypto/src/asn1/Asn1OutputStream.cs
@@ -1,6 +1,6 @@
 using System;
-using System.IO;
 using System.Diagnostics;
+using System.IO;
 #if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER
 using System.Buffers.Binary;
 using System.Numerics;
@@ -24,13 +24,9 @@ namespace Org.BouncyCastle.Asn1
         public static Asn1OutputStream Create(Stream output, string encoding)
         {
             if (Asn1Encodable.Der.Equals(encoding))
-            {
                 return new DerOutputStream(output);
-            }
-            else
-            {
-                return new Asn1OutputStream(output);
-            }
+
+            return new Asn1OutputStream(output);
         }
 
         internal Asn1OutputStream(Stream os)
diff --git a/crypto/src/asn1/BERSequenceGenerator.cs b/crypto/src/asn1/BERSequenceGenerator.cs
index 5ea2c9b82..64ac23c57 100644
--- a/crypto/src/asn1/BERSequenceGenerator.cs
+++ b/crypto/src/asn1/BERSequenceGenerator.cs
@@ -5,17 +5,13 @@ namespace Org.BouncyCastle.Asn1
 	public class BerSequenceGenerator
 		: BerGenerator
 	{
-		public BerSequenceGenerator(
-			Stream outStream)
+		public BerSequenceGenerator(Stream outStream)
 			: base(outStream)
 		{
 			WriteBerHeader(Asn1Tags.Constructed | Asn1Tags.Sequence);
 		}
 
-		public BerSequenceGenerator(
-			Stream	outStream,
-			int		tagNo,
-			bool	isExplicit)
+		public BerSequenceGenerator(Stream outStream, int tagNo, bool isExplicit)
 			: base(outStream, tagNo, isExplicit)
 		{
 			WriteBerHeader(Asn1Tags.Constructed | Asn1Tags.Sequence);
diff --git a/crypto/src/asn1/BERSetGenerator.cs b/crypto/src/asn1/BERSetGenerator.cs
index 72b1f903a..29fc37b93 100644
--- a/crypto/src/asn1/BERSetGenerator.cs
+++ b/crypto/src/asn1/BERSetGenerator.cs
@@ -5,17 +5,13 @@ namespace Org.BouncyCastle.Asn1
 	public class BerSetGenerator
 		: BerGenerator
 	{
-		public BerSetGenerator(
-			Stream outStream)
+		public BerSetGenerator(Stream outStream)
 			: base(outStream)
 		{
 			WriteBerHeader(Asn1Tags.Constructed | Asn1Tags.Set);
 		}
 
-		public BerSetGenerator(
-			Stream	outStream,
-			int		tagNo,
-			bool	isExplicit)
+		public BerSetGenerator(Stream outStream, int tagNo, bool isExplicit)
 			: base(outStream, tagNo, isExplicit)
 		{
 			WriteBerHeader(Asn1Tags.Constructed | Asn1Tags.Set);
diff --git a/crypto/src/asn1/DLTaggedObjectParser.cs b/crypto/src/asn1/DLTaggedObjectParser.cs
index 3a89a69cd..75e8995be 100644
--- a/crypto/src/asn1/DLTaggedObjectParser.cs
+++ b/crypto/src/asn1/DLTaggedObjectParser.cs
@@ -71,4 +71,3 @@ namespace Org.BouncyCastle.Asn1
 		}
     }
 }
-
diff --git a/crypto/src/asn1/DerObjectIdentifier.cs b/crypto/src/asn1/DerObjectIdentifier.cs
index cb5771958..06a7b25f3 100644
--- a/crypto/src/asn1/DerObjectIdentifier.cs
+++ b/crypto/src/asn1/DerObjectIdentifier.cs
@@ -80,7 +80,7 @@ namespace Org.BouncyCastle.Asn1
 
         private const long LongLimit = (long.MaxValue >> 7) - 0x7F;
 
-        private static readonly DerObjectIdentifier[] cache = new DerObjectIdentifier[1024];
+        private static readonly DerObjectIdentifier[] Cache = new DerObjectIdentifier[1024];
 
         private readonly string identifier;
         private byte[] contents;
@@ -208,15 +208,15 @@ namespace Org.BouncyCastle.Asn1
             int hashCode = Arrays.GetHashCode(contents);
             int first = hashCode & 1023;
 
-            lock (cache)
+            lock (Cache)
             {
-                DerObjectIdentifier entry = cache[first];
+                DerObjectIdentifier entry = Cache[first];
                 if (entry != null && Arrays.AreEqual(contents, entry.GetContents()))
                 {
                     return entry;
                 }
 
-                return cache[first] = new DerObjectIdentifier(contents, clone);
+                return Cache[first] = new DerObjectIdentifier(contents, clone);
             }
         }
 
diff --git a/crypto/src/asn1/cmp/PKIHeader.cs b/crypto/src/asn1/cmp/PKIHeader.cs
index 7ed914e6a..7db9cde1d 100644
--- a/crypto/src/asn1/cmp/PKIHeader.cs
+++ b/crypto/src/asn1/cmp/PKIHeader.cs
@@ -76,13 +76,13 @@ namespace Org.BouncyCastle.Asn1.Cmp
 
         public static PkiHeader GetInstance(object obj)
         {
-            if (obj is PkiHeader)
-                return (PkiHeader)obj;
+            if (obj is PkiHeader pkiHeader)
+                return pkiHeader;
 
-            if (obj is Asn1Sequence)
-                return new PkiHeader((Asn1Sequence)obj);
+            if (obj is Asn1Sequence asn1Sequence)
+                return new PkiHeader(asn1Sequence);
 
-            throw new ArgumentException("Invalid object: " + Platform.GetTypeName(obj), "obj");
+            throw new ArgumentException("Invalid object: " + Platform.GetTypeName(obj), nameof(obj));
         }
 
         public PkiHeader(
@@ -160,16 +160,7 @@ namespace Org.BouncyCastle.Asn1.Cmp
 
         public virtual InfoTypeAndValue[] GetGeneralInfo()
         {
-            if (generalInfo == null)
-            {
-                return null;
-            }
-            InfoTypeAndValue[] results = new InfoTypeAndValue[generalInfo.Count];
-            for (int i = 0; i < results.Length; i++)
-            {
-                results[i] = InfoTypeAndValue.GetInstance(generalInfo[i]);
-            }
-            return results;
+            return generalInfo?.MapElements(InfoTypeAndValue.GetInstance);
         }
 
         /**
diff --git a/crypto/src/asn1/cmp/PKIHeaderBuilder.cs b/crypto/src/asn1/cmp/PKIHeaderBuilder.cs
index cbefc73b8..ab8db958a 100644
--- a/crypto/src/asn1/cmp/PKIHeaderBuilder.cs
+++ b/crypto/src/asn1/cmp/PKIHeaderBuilder.cs
@@ -189,15 +189,15 @@ namespace Org.BouncyCastle.Asn1.Cmp
 		public virtual PkiHeader Build()
 		{
 			Asn1EncodableVector v = new Asn1EncodableVector(pvno, sender, recipient);
-			AddOptional(v, 0, messageTime);
-			AddOptional(v, 1, protectionAlg);
-			AddOptional(v, 2, senderKID);
-			AddOptional(v, 3, recipKID);
-			AddOptional(v, 4, transactionID);
-			AddOptional(v, 5, senderNonce);
-			AddOptional(v, 6, recipNonce);
-			AddOptional(v, 7, freeText);
-			AddOptional(v, 8, generalInfo);
+            v.AddOptionalTagged(true, 0, messageTime);
+            v.AddOptionalTagged(true, 1, protectionAlg);
+			v.AddOptionalTagged(true, 2, senderKID);
+			v.AddOptionalTagged(true, 3, recipKID);
+			v.AddOptionalTagged(true, 4, transactionID);
+			v.AddOptionalTagged(true, 5, senderNonce);
+			v.AddOptionalTagged(true, 6, recipNonce);
+			v.AddOptionalTagged(true, 7, freeText);
+			v.AddOptionalTagged(true, 8, generalInfo);
 
 			messageTime = null;
 			protectionAlg = null;
@@ -211,13 +211,5 @@ namespace Org.BouncyCastle.Asn1.Cmp
 
 			return PkiHeader.GetInstance(new DerSequence(v));
 		}
-
-		private void AddOptional(Asn1EncodableVector v, int tagNo, Asn1Encodable obj)
-		{
-			if (obj != null)
-			{
-				v.Add(new DerTaggedObject(true, tagNo, obj));
-			}
-		}
 	}
 }
diff --git a/crypto/src/asn1/cmp/PKIMessage.cs b/crypto/src/asn1/cmp/PKIMessage.cs
index c87bf2126..9ac54b3da 100644
--- a/crypto/src/asn1/cmp/PKIMessage.cs
+++ b/crypto/src/asn1/cmp/PKIMessage.cs
@@ -96,15 +96,7 @@ namespace Org.BouncyCastle.Asn1.Cmp
 
         public virtual CmpCertificate[] GetExtraCerts()
         {
-            if (extraCerts == null)
-                return null;
-
-            CmpCertificate[] results = new CmpCertificate[extraCerts.Count];
-            for (int i = 0; i < results.Length; ++i)
-            {
-                results[i] = CmpCertificate.GetInstance(extraCerts[i]);
-            }
-            return results;
+            return extraCerts?.MapElements(CmpCertificate.GetInstance);
         }
 
         /**
diff --git a/crypto/src/asn1/cmp/PKIMessages.cs b/crypto/src/asn1/cmp/PKIMessages.cs
index 0008f476a..8e2e8a1ed 100644
--- a/crypto/src/asn1/cmp/PKIMessages.cs
+++ b/crypto/src/asn1/cmp/PKIMessages.cs
@@ -7,37 +7,32 @@ namespace Org.BouncyCastle.Asn1.Cmp
     public class PkiMessages
         : Asn1Encodable
     {
-        private Asn1Sequence content;
+        private Asn1Sequence m_content;
 
         internal PkiMessages(Asn1Sequence seq)
         {
-            content = seq;
+            m_content = seq;
         }
 
         public static PkiMessages GetInstance(object obj)
         {
-            if (obj is PkiMessages)
-                return (PkiMessages)obj;
+            if (obj is PkiMessages pkiMessages)
+                return pkiMessages;
 
-            if (obj is Asn1Sequence)
-                return new PkiMessages((Asn1Sequence)obj);
+            if (obj is Asn1Sequence asn1Sequence)
+                return new PkiMessages(asn1Sequence);
 
-            throw new ArgumentException("Invalid object: " + Platform.GetTypeName(obj), "obj");
+            throw new ArgumentException("Invalid object: " + Platform.GetTypeName(obj), nameof(obj));
         }
 
 		public PkiMessages(params PkiMessage[] msgs)
         {
-            content = new DerSequence(msgs);
+            m_content = new DerSequence(msgs);
         }
 
         public virtual PkiMessage[] ToPkiMessageArray()
         {
-            PkiMessage[] result = new PkiMessage[content.Count];
-            for (int i = 0; i != result.Length; ++i)
-            {
-                result[i] = PkiMessage.GetInstance(content[i]);
-            }
-            return result;
+            return m_content.MapElements(PkiMessage.GetInstance);
         }
 
         /**
@@ -48,7 +43,7 @@ namespace Org.BouncyCastle.Asn1.Cmp
          */
         public override Asn1Object ToAsn1Object()
         {
-            return content;
+            return m_content;
         }
     }
 }
diff --git a/crypto/src/asn1/cms/ContentInfoParser.cs b/crypto/src/asn1/cms/ContentInfoParser.cs
index 750d8ba7a..e423be848 100644
--- a/crypto/src/asn1/cms/ContentInfoParser.cs
+++ b/crypto/src/asn1/cms/ContentInfoParser.cs
@@ -22,10 +22,7 @@ namespace Org.BouncyCastle.Asn1.Cms
 			m_content = (Asn1TaggedObjectParser)seq.ReadObject();
 		}
 
-		public DerObjectIdentifier ContentType
-		{
-			get { return m_contentType; }
-		}
+		public DerObjectIdentifier ContentType => m_contentType;
 
 		public IAsn1Convertible GetContent(int tag)
 		{
diff --git a/crypto/src/asn1/cms/EncryptedContentInfoParser.cs b/crypto/src/asn1/cms/EncryptedContentInfoParser.cs
index 09434d7ef..42f72164a 100644
--- a/crypto/src/asn1/cms/EncryptedContentInfoParser.cs
+++ b/crypto/src/asn1/cms/EncryptedContentInfoParser.cs
@@ -15,32 +15,24 @@ namespace Org.BouncyCastle.Asn1.Cms
 	*/
 	public class EncryptedContentInfoParser
 	{
-		private DerObjectIdentifier		_contentType;
-		private AlgorithmIdentifier		_contentEncryptionAlgorithm;
-		private Asn1TaggedObjectParser	_encryptedContent;
+		private readonly DerObjectIdentifier m_contentType;
+		private readonly AlgorithmIdentifier m_contentEncryptionAlgorithm;
+		private readonly Asn1TaggedObjectParser	m_encryptedContent;
 
-		public EncryptedContentInfoParser(
-			Asn1SequenceParser seq)
+		public EncryptedContentInfoParser(Asn1SequenceParser seq)
 		{
-			_contentType = (DerObjectIdentifier)seq.ReadObject();
-			_contentEncryptionAlgorithm = AlgorithmIdentifier.GetInstance(seq.ReadObject().ToAsn1Object());
-			_encryptedContent = (Asn1TaggedObjectParser)seq.ReadObject();
+			m_contentType = (DerObjectIdentifier)seq.ReadObject();
+			m_contentEncryptionAlgorithm = AlgorithmIdentifier.GetInstance(seq.ReadObject().ToAsn1Object());
+			m_encryptedContent = (Asn1TaggedObjectParser)seq.ReadObject();
 		}
 
-		public DerObjectIdentifier ContentType
-		{
-			get { return _contentType; }
-		}
+		public DerObjectIdentifier ContentType => m_contentType;
 
-		public AlgorithmIdentifier ContentEncryptionAlgorithm
-		{
-			get { return _contentEncryptionAlgorithm; }
-		}
+		public AlgorithmIdentifier ContentEncryptionAlgorithm => m_contentEncryptionAlgorithm;
 
-		public IAsn1Convertible GetEncryptedContent(
-			int tag)
+		public IAsn1Convertible GetEncryptedContent(int tag)
 		{
-			return Asn1Utilities.ParseContextBaseUniversal(_encryptedContent, 0, false, tag);
+			return Asn1Utilities.ParseContextBaseUniversal(m_encryptedContent, 0, false, tag);
 		}
 	}
 }
diff --git a/crypto/src/asn1/cms/EnvelopedDataParser.cs b/crypto/src/asn1/cms/EnvelopedDataParser.cs
index a86608bb4..06e10c104 100644
--- a/crypto/src/asn1/cms/EnvelopedDataParser.cs
+++ b/crypto/src/asn1/cms/EnvelopedDataParser.cs
@@ -2,7 +2,7 @@ using System;
 
 namespace Org.BouncyCastle.Asn1.Cms
 {
-	/**
+    /**
 	* Produce an object suitable for an Asn1OutputStream.
 	* <pre>
 	* EnvelopedData ::= SEQUENCE {
@@ -14,96 +14,96 @@ namespace Org.BouncyCastle.Asn1.Cms
 	* }
 	* </pre>
 	*/
-	public class EnvelopedDataParser
-	{
-		private Asn1SequenceParser	_seq;
-		private DerInteger			_version;
-		private IAsn1Convertible	_nextObject;
-		private bool				_originatorInfoCalled;
-
-		public EnvelopedDataParser(
-			Asn1SequenceParser seq)
-		{
-			this._seq = seq;
-			this._version = (DerInteger)seq.ReadObject();
-		}
-
-		public DerInteger Version
-		{
-			get { return _version; }
-		}
-
-		public OriginatorInfo GetOriginatorInfo() 
-		{
-			_originatorInfoCalled = true; 
-
-			if (_nextObject == null)
-			{
-				_nextObject = _seq.ReadObject();
-			}
-
-			if (_nextObject is Asn1TaggedObjectParser o)
-			{
-				if (o.HasContextTag(0))
-				{
-					Asn1SequenceParser originatorInfo = (Asn1SequenceParser)o.ParseBaseUniversal(false, Asn1Tags.Sequence);
-					_nextObject = null;
-					return OriginatorInfo.GetInstance(originatorInfo.ToAsn1Object());
-				}
-			}
-
-			return null;
-		}
-
-		public Asn1SetParser GetRecipientInfos()
-		{
-			if (!_originatorInfoCalled)
-			{
-				GetOriginatorInfo();
-			}
-
-			if (_nextObject == null)
-			{
-				_nextObject = _seq.ReadObject();
-			}
-
-			Asn1SetParser recipientInfos = (Asn1SetParser)_nextObject;
-			_nextObject = null;
-			return recipientInfos;
-		}
-
-		public EncryptedContentInfoParser GetEncryptedContentInfo()
-		{
-			if (_nextObject == null)
-			{
-				_nextObject = _seq.ReadObject();
-			}
-
-			if (_nextObject != null)
-			{
-				Asn1SequenceParser o = (Asn1SequenceParser) _nextObject;
-				_nextObject = null;
-				return new EncryptedContentInfoParser(o);
-			}
-
-			return null;
-		}
-
-		public Asn1SetParser GetUnprotectedAttrs()
-		{
-			if (_nextObject == null)
-			{
-				_nextObject = _seq.ReadObject();
-			}
-
-			if (_nextObject != null)
-			{
-				Asn1TaggedObjectParser o = (Asn1TaggedObjectParser)_nextObject;
-				_nextObject = null;
-				return (Asn1SetParser)Asn1Utilities.ParseContextBaseUniversal(o, 1, false, Asn1Tags.SetOf);
-			}
-
-			return null;
-		}
-	}
+    public class EnvelopedDataParser
+    {
+        private Asn1SequenceParser _seq;
+        private DerInteger _version;
+        private IAsn1Convertible _nextObject;
+        private bool _originatorInfoCalled;
+
+        public EnvelopedDataParser(
+            Asn1SequenceParser seq)
+        {
+            this._seq = seq;
+            this._version = (DerInteger)seq.ReadObject();
+        }
+
+        public DerInteger Version
+        {
+            get { return _version; }
+        }
+
+        public OriginatorInfo GetOriginatorInfo()
+        {
+            _originatorInfoCalled = true;
+
+            if (_nextObject == null)
+            {
+                _nextObject = _seq.ReadObject();
+            }
+
+            if (_nextObject is Asn1TaggedObjectParser o)
+            {
+                if (o.HasContextTag(0))
+                {
+                    Asn1SequenceParser originatorInfo = (Asn1SequenceParser)o.ParseBaseUniversal(false, Asn1Tags.Sequence);
+                    _nextObject = null;
+                    return OriginatorInfo.GetInstance(originatorInfo.ToAsn1Object());
+                }
+            }
+
+            return null;
+        }
+
+        public Asn1SetParser GetRecipientInfos()
+        {
+            if (!_originatorInfoCalled)
+            {
+                GetOriginatorInfo();
+            }
+
+            if (_nextObject == null)
+            {
+                _nextObject = _seq.ReadObject();
+            }
+
+            Asn1SetParser recipientInfos = (Asn1SetParser)_nextObject;
+            _nextObject = null;
+            return recipientInfos;
+        }
+
+        public EncryptedContentInfoParser GetEncryptedContentInfo()
+        {
+            if (_nextObject == null)
+            {
+                _nextObject = _seq.ReadObject();
+            }
+
+            if (_nextObject != null)
+            {
+                Asn1SequenceParser o = (Asn1SequenceParser)_nextObject;
+                _nextObject = null;
+                return new EncryptedContentInfoParser(o);
+            }
+
+            return null;
+        }
+
+        public Asn1SetParser GetUnprotectedAttrs()
+        {
+            if (_nextObject == null)
+            {
+                _nextObject = _seq.ReadObject();
+            }
+
+            if (_nextObject != null)
+            {
+                Asn1TaggedObjectParser o = (Asn1TaggedObjectParser)_nextObject;
+                _nextObject = null;
+                return (Asn1SetParser)Asn1Utilities.ParseContextBaseUniversal(o, 1, false, Asn1Tags.SetOf);
+            }
+
+            return null;
+        }
+    }
 }
diff --git a/crypto/src/asn1/cms/KEKIdentifier.cs b/crypto/src/asn1/cms/KEKIdentifier.cs
index 36ab94f52..70ae8c438 100644
--- a/crypto/src/asn1/cms/KEKIdentifier.cs
+++ b/crypto/src/asn1/cms/KEKIdentifier.cs
@@ -21,19 +21,18 @@ namespace Org.BouncyCastle.Asn1.Cms
             this.other = other;
         }
 
-		public KekIdentifier(
-            Asn1Sequence seq)
+		public KekIdentifier(Asn1Sequence seq)
         {
-            keyIdentifier = (Asn1OctetString) seq[0];
+            keyIdentifier = (Asn1OctetString)seq[0];
 
 			switch (seq.Count)
             {
             case 1:
 				break;
             case 2:
-				if (seq[1] is Asn1GeneralizedTime)
+				if (seq[1] is Asn1GeneralizedTime asn1GeneralizedTime)
 				{
-					date = (Asn1GeneralizedTime) seq[1];
+					date = asn1GeneralizedTime;
 				}
 				else
 				{
@@ -41,7 +40,7 @@ namespace Org.BouncyCastle.Asn1.Cms
 				}
 				break;
             case 3:
-				date  = (Asn1GeneralizedTime) seq[1];
+				date = (Asn1GeneralizedTime)seq[1];
 				other = OtherKeyAttribute.GetInstance(seq[2]);
 				break;
             default:
diff --git a/crypto/src/asn1/cms/RecipientKeyIdentifier.cs b/crypto/src/asn1/cms/RecipientKeyIdentifier.cs
index dea9ce09d..512025808 100644
--- a/crypto/src/asn1/cms/RecipientKeyIdentifier.cs
+++ b/crypto/src/asn1/cms/RecipientKeyIdentifier.cs
@@ -37,20 +37,18 @@ namespace Org.BouncyCastle.Asn1.Cms
 			this.other = other;
 		}
 
-		public RecipientKeyIdentifier(
-            Asn1Sequence seq)
+		public RecipientKeyIdentifier(Asn1Sequence seq)
         {
-            subjectKeyIdentifier = Asn1OctetString.GetInstance(
-				seq[0]);
+            subjectKeyIdentifier = Asn1OctetString.GetInstance(seq[0]);
 
 			switch(seq.Count)
             {
 				case 1:
 					break;
 				case 2:
-					if (seq[1] is Asn1GeneralizedTime)
+					if (seq[1] is Asn1GeneralizedTime asn1GeneralizedTime)
 					{
-						date = (Asn1GeneralizedTime)seq[1];
+						date = asn1GeneralizedTime;
 					}
 					else
 					{
@@ -58,7 +56,7 @@ namespace Org.BouncyCastle.Asn1.Cms
 					}
 					break;
 				case 3:
-					date  = (Asn1GeneralizedTime)seq[1];
+					date = (Asn1GeneralizedTime)seq[1];
 					other = OtherKeyAttribute.GetInstance(seq[2]);
 					break;
 				default:
diff --git a/crypto/src/asn1/cms/SignedDataParser.cs b/crypto/src/asn1/cms/SignedDataParser.cs
index 64114f292..3afbe09f4 100644
--- a/crypto/src/asn1/cms/SignedDataParser.cs
+++ b/crypto/src/asn1/cms/SignedDataParser.cs
@@ -5,7 +5,7 @@ using Org.BouncyCastle.Utilities;
 
 namespace Org.BouncyCastle.Asn1.Cms
 {
-	/**
+    /**
 	* <pre>
 	* SignedData ::= SEQUENCE {
 	*     version CMSVersion,
@@ -17,102 +17,102 @@ namespace Org.BouncyCastle.Asn1.Cms
 	*   }
 	* </pre>
 	*/
-	public class SignedDataParser
-	{
-		private Asn1SequenceParser	_seq;
-		private DerInteger			_version;
-		private object				_nextObject;
-		private bool				_certsCalled;
-		private bool				_crlsCalled;
-
-		public static SignedDataParser GetInstance(
-			object o)
-		{
-			if (o is Asn1Sequence)
-				return new SignedDataParser(((Asn1Sequence)o).Parser);
-
-			if (o is Asn1SequenceParser)
-				return new SignedDataParser((Asn1SequenceParser)o);
+    public class SignedDataParser
+    {
+        private Asn1SequenceParser _seq;
+        private DerInteger _version;
+        private object _nextObject;
+        private bool _certsCalled;
+        private bool _crlsCalled;
+
+        public static SignedDataParser GetInstance(
+            object o)
+        {
+            if (o is Asn1Sequence)
+                return new SignedDataParser(((Asn1Sequence)o).Parser);
+
+            if (o is Asn1SequenceParser)
+                return new SignedDataParser((Asn1SequenceParser)o);
 
             throw new IOException("unknown object encountered: " + Platform.GetTypeName(o));
-		}
-
-		public SignedDataParser(
-			Asn1SequenceParser seq)
-		{
-			this._seq = seq;
-			this._version = (DerInteger)seq.ReadObject();
-		}
-
-		public DerInteger Version
-		{
-			get { return _version; }
-		}
-
-		public Asn1SetParser GetDigestAlgorithms()
-		{
-			return (Asn1SetParser)_seq.ReadObject();
-		}
-
-		public ContentInfoParser GetEncapContentInfo()
-		{
-			return new ContentInfoParser((Asn1SequenceParser)_seq.ReadObject());
-		}
-
-		public Asn1SetParser GetCertificates()
-		{
-			_certsCalled = true;
-			_nextObject = _seq.ReadObject();
-
-			if (_nextObject is Asn1TaggedObjectParser o)
-			{
-				if (o.HasContextTag(0))
-				{
-					Asn1SetParser certs = (Asn1SetParser)o.ParseBaseUniversal(false, Asn1Tags.SetOf);
-					_nextObject = null;
-					return certs;
-				}
-			}
-
-			return null;
-		}
-
-		public Asn1SetParser GetCrls()
-		{
-			if (!_certsCalled)
-				throw new IOException("GetCerts() has not been called.");
-
-			_crlsCalled = true;
-
-			if (_nextObject == null)
-			{
-				_nextObject = _seq.ReadObject();
-			}
-
-			if (_nextObject is Asn1TaggedObjectParser o)
-			{
-				if (o.HasContextTag(1))
-				{
-					Asn1SetParser crls = (Asn1SetParser)o.ParseBaseUniversal(false, Asn1Tags.SetOf);
-					_nextObject = null;
-					return crls;
-				}
-			}
+        }
+
+        public SignedDataParser(
+            Asn1SequenceParser seq)
+        {
+            this._seq = seq;
+            this._version = (DerInteger)seq.ReadObject();
+        }
+
+        public DerInteger Version
+        {
+            get { return _version; }
+        }
+
+        public Asn1SetParser GetDigestAlgorithms()
+        {
+            return (Asn1SetParser)_seq.ReadObject();
+        }
+
+        public ContentInfoParser GetEncapContentInfo()
+        {
+            return new ContentInfoParser((Asn1SequenceParser)_seq.ReadObject());
+        }
+
+        public Asn1SetParser GetCertificates()
+        {
+            _certsCalled = true;
+            _nextObject = _seq.ReadObject();
+
+            if (_nextObject is Asn1TaggedObjectParser o)
+            {
+                if (o.HasContextTag(0))
+                {
+                    Asn1SetParser certs = (Asn1SetParser)o.ParseBaseUniversal(false, Asn1Tags.SetOf);
+                    _nextObject = null;
+                    return certs;
+                }
+            }
 
             return null;
         }
 
-		public Asn1SetParser GetSignerInfos()
-		{
-			if (!_certsCalled || !_crlsCalled)
-				throw new IOException("GetCerts() and/or GetCrls() has not been called.");
+        public Asn1SetParser GetCrls()
+        {
+            if (!_certsCalled)
+                throw new IOException("GetCerts() has not been called.");
+
+            _crlsCalled = true;
+
+            if (_nextObject == null)
+            {
+                _nextObject = _seq.ReadObject();
+            }
 
-			if (_nextObject == null)
-			{
-				_nextObject = _seq.ReadObject();
-			}
+            if (_nextObject is Asn1TaggedObjectParser o)
+            {
+                if (o.HasContextTag(1))
+                {
+                    Asn1SetParser crls = (Asn1SetParser)o.ParseBaseUniversal(false, Asn1Tags.SetOf);
+                    _nextObject = null;
+                    return crls;
+                }
+            }
 
-			return (Asn1SetParser)_nextObject;
-		}
-	}
+            return null;
+        }
+
+        public Asn1SetParser GetSignerInfos()
+        {
+            if (!_certsCalled || !_crlsCalled)
+                throw new IOException("GetCerts() and/or GetCrls() has not been called.");
+
+            if (_nextObject == null)
+            {
+                _nextObject = _seq.ReadObject();
+            }
+
+            return (Asn1SetParser)_nextObject;
+        }
+    }
 }
diff --git a/crypto/src/asn1/cms/Time.cs b/crypto/src/asn1/cms/Time.cs
index 7b6b49c30..19bc1a633 100644
--- a/crypto/src/asn1/cms/Time.cs
+++ b/crypto/src/asn1/cms/Time.cs
@@ -31,7 +31,7 @@ namespace Org.BouncyCastle.Asn1.Cms
 
         public Time(Asn1GeneralizedTime generalizedTime)
         {
-            this.m_timeObject = generalizedTime ?? throw new ArgumentNullException(nameof(generalizedTime));
+            m_timeObject = generalizedTime ?? throw new ArgumentNullException(nameof(generalizedTime));
         }
 
         public Time(Asn1UtcTime utcTime)
@@ -42,7 +42,7 @@ namespace Org.BouncyCastle.Asn1.Cms
             // Validate utcTime is in the appropriate year range
             utcTime.ToDateTime(2049);
 
-            this.m_timeObject = utcTime;
+            m_timeObject = utcTime;
         }
 
 		/**
diff --git a/crypto/src/asn1/crmf/CertTemplateBuilder.cs b/crypto/src/asn1/crmf/CertTemplateBuilder.cs
index 51c73c4e1..d26e6399c 100644
--- a/crypto/src/asn1/crmf/CertTemplateBuilder.cs
+++ b/crypto/src/asn1/crmf/CertTemplateBuilder.cs
@@ -99,27 +99,17 @@ namespace Org.BouncyCastle.Asn1.Crmf
         public virtual CertTemplate Build()
         {
             Asn1EncodableVector v = new Asn1EncodableVector();
-
-            AddOptional(v, 0, false, version);
-            AddOptional(v, 1, false, serialNumber);
-            AddOptional(v, 2, false, signingAlg);
-            AddOptional(v, 3, true, issuer); // CHOICE
-            AddOptional(v, 4, false, validity);
-            AddOptional(v, 5, true, subject); // CHOICE
-            AddOptional(v, 6, false, publicKey);
-            AddOptional(v, 7, false, issuerUID);
-            AddOptional(v, 8, false, subjectUID);
-            AddOptional(v, 9, false, extensions);
-
+            v.AddOptionalTagged(false, 0, version);
+            v.AddOptionalTagged(false, 1, serialNumber);
+            v.AddOptionalTagged(false, 2, signingAlg);
+            v.AddOptionalTagged(true, 3, issuer); // CHOICE
+            v.AddOptionalTagged(false, 4, validity);
+            v.AddOptionalTagged(true, 5, subject); // CHOICE
+            v.AddOptionalTagged(false, 6, publicKey);
+            v.AddOptionalTagged(false, 7, issuerUID);
+            v.AddOptionalTagged(false, 8, subjectUID);
+            v.AddOptionalTagged(false, 9, extensions);
             return CertTemplate.GetInstance(new DerSequence(v));
         }
-
-        private void AddOptional(Asn1EncodableVector v, int tagNo, bool isExplicit, Asn1Encodable obj)
-        {
-            if (obj != null)
-            {
-                v.Add(new DerTaggedObject(isExplicit, tagNo, obj));
-            }
-        }
     }
 }
diff --git a/crypto/src/asn1/esf/CertificateValues.cs b/crypto/src/asn1/esf/CertificateValues.cs
index ee0d2830c..8329e45f8 100644
--- a/crypto/src/asn1/esf/CertificateValues.cs
+++ b/crypto/src/asn1/esf/CertificateValues.cs
@@ -15,69 +15,58 @@ namespace Org.BouncyCastle.Asn1.Esf
 	public class CertificateValues
 		: Asn1Encodable
 	{
-		private readonly Asn1Sequence certificates;
+		private readonly Asn1Sequence m_certificates;
 
-		public static CertificateValues GetInstance(
-			object obj)
+		public static CertificateValues GetInstance(object obj)
 		{
-			if (obj == null || obj is CertificateValues)
-				return (CertificateValues) obj;
+			if (obj == null)
+				return null;
 
-			if (obj is Asn1Sequence)
-				return new CertificateValues((Asn1Sequence) obj);
+			if (obj is CertificateValues certificateValues)
+				return certificateValues;
 
-			throw new ArgumentException(
-				"Unknown object in 'CertificateValues' factory: "
-                    + Platform.GetTypeName(obj),
-				"obj");
+			if (obj is Asn1Sequence asn1Sequence)
+				return new CertificateValues(asn1Sequence);
+
+			throw new ArgumentException("Unknown object in 'CertificateValues' factory: " + Platform.GetTypeName(obj),
+				nameof(obj));
 		}
 
-		private CertificateValues(
-			Asn1Sequence seq)
+		private CertificateValues(Asn1Sequence seq)
 		{
 			if (seq == null)
-				throw new ArgumentNullException("seq");
+				throw new ArgumentNullException(nameof(seq));
 
-			foreach (Asn1Encodable ae in seq)
-			{
-				X509CertificateStructure.GetInstance(ae.ToAsn1Object());
-			}
+			// Validate
+            seq.MapElements(element => X509CertificateStructure.GetInstance(element.ToAsn1Object()));
 
-			this.certificates = seq;
+			m_certificates = seq;
 		}
 
-		public CertificateValues(
-			params X509CertificateStructure[] certificates)
+		public CertificateValues(params X509CertificateStructure[] certificates)
 		{
 			if (certificates == null)
-				throw new ArgumentNullException("certificates");
+				throw new ArgumentNullException(nameof(certificates));
 
-			this.certificates = new DerSequence(certificates);
+			m_certificates = new DerSequence(certificates);
 		}
 
-		public CertificateValues(
-			IEnumerable<X509CertificateStructure> certificates)
+		public CertificateValues(IEnumerable<X509CertificateStructure> certificates)
 		{
 			if (certificates == null)
-				throw new ArgumentNullException("certificates");
+                throw new ArgumentNullException(nameof(certificates));
 
-			this.certificates = new DerSequence(
-				Asn1EncodableVector.FromEnumerable(certificates));
+            m_certificates = new DerSequence(Asn1EncodableVector.FromEnumerable(certificates));
 		}
 
 		public X509CertificateStructure[] GetCertificates()
 		{
-			X509CertificateStructure[] result = new X509CertificateStructure[certificates.Count];
-			for (int i = 0; i < certificates.Count; ++i)
-			{
-				result[i] = X509CertificateStructure.GetInstance(certificates[i]);
-			}
-			return result;
+			return m_certificates.MapElements(element => X509CertificateStructure.GetInstance(element.ToAsn1Object()));
 		}
 
 		public override Asn1Object ToAsn1Object()
 		{
-			return certificates;
+			return m_certificates;
 		}
  	}
 }
diff --git a/crypto/src/asn1/esf/CompleteCertificateRefs.cs b/crypto/src/asn1/esf/CompleteCertificateRefs.cs
index 2ed66e3dc..24727dc25 100644
--- a/crypto/src/asn1/esf/CompleteCertificateRefs.cs
+++ b/crypto/src/asn1/esf/CompleteCertificateRefs.cs
@@ -14,69 +14,58 @@ namespace Org.BouncyCastle.Asn1.Esf
 	public class CompleteCertificateRefs
 		: Asn1Encodable
 	{
-		private readonly Asn1Sequence otherCertIDs;
+		private readonly Asn1Sequence m_otherCertIDs;
 
-		public static CompleteCertificateRefs GetInstance(
-			object obj)
+		public static CompleteCertificateRefs GetInstance(object obj)
 		{
-			if (obj == null || obj is CompleteCertificateRefs)
-				return (CompleteCertificateRefs) obj;
+			if (obj == null)
+				return null;
 
-			if (obj is Asn1Sequence)
-				return new CompleteCertificateRefs((Asn1Sequence) obj);
+            if (obj is CompleteCertificateRefs completeCertificateRefs)
+				return completeCertificateRefs;
 
-			throw new ArgumentException(
-				"Unknown object in 'CompleteCertificateRefs' factory: "
-                    + Platform.GetTypeName(obj),
-				"obj");
+			if (obj is Asn1Sequence asn1Sequence)
+				return new CompleteCertificateRefs(asn1Sequence);
+
+			throw new ArgumentException("Unknown object in 'CompleteCertificateRefs' factory: " + Platform.GetTypeName(obj),
+				nameof(obj));
 		}
 
-		private CompleteCertificateRefs(
-			Asn1Sequence seq)
+		private CompleteCertificateRefs(Asn1Sequence seq)
 		{
 			if (seq == null)
-				throw new ArgumentNullException("seq");
+				throw new ArgumentNullException(nameof(seq));
 
-			foreach (Asn1Encodable ae in seq)
-			{
-				OtherCertID.GetInstance(ae.ToAsn1Object());
-			}
+            // Validate
+            seq.MapElements(element => OtherCertID.GetInstance(element.ToAsn1Object()));
 
-			this.otherCertIDs = seq;
+            m_otherCertIDs = seq;
 		}
 
-		public CompleteCertificateRefs(
-			params OtherCertID[] otherCertIDs)
+		public CompleteCertificateRefs(params OtherCertID[] otherCertIDs)
 		{
 			if (otherCertIDs == null)
-				throw new ArgumentNullException("otherCertIDs");
+				throw new ArgumentNullException(nameof(otherCertIDs));
 
-			this.otherCertIDs = new DerSequence(otherCertIDs);
+			m_otherCertIDs = new DerSequence(otherCertIDs);
 		}
 
-		public CompleteCertificateRefs(
-			IEnumerable<OtherCertID> otherCertIDs)
+		public CompleteCertificateRefs(IEnumerable<OtherCertID> otherCertIDs)
 		{
 			if (otherCertIDs == null)
-				throw new ArgumentNullException("otherCertIDs");
+                throw new ArgumentNullException(nameof(otherCertIDs));
 
-			this.otherCertIDs = new DerSequence(
-				Asn1EncodableVector.FromEnumerable(otherCertIDs));
+            m_otherCertIDs = new DerSequence(Asn1EncodableVector.FromEnumerable(otherCertIDs));
 		}
 
 		public OtherCertID[] GetOtherCertIDs()
 		{
-			OtherCertID[] result = new OtherCertID[otherCertIDs.Count];
-			for (int i = 0; i < otherCertIDs.Count; ++i)
-			{
-				result[i] = OtherCertID.GetInstance(otherCertIDs[i].ToAsn1Object());
-			}
-			return result;
+            return m_otherCertIDs.MapElements(element => OtherCertID.GetInstance(element.ToAsn1Object()));
 		}
 
 		public override Asn1Object ToAsn1Object()
 		{
-			return otherCertIDs;
+			return m_otherCertIDs;
 		}
 	}
 }
diff --git a/crypto/src/asn1/esf/CompleteRevocationRefs.cs b/crypto/src/asn1/esf/CompleteRevocationRefs.cs
index 9942cec8f..2c120f0f9 100644
--- a/crypto/src/asn1/esf/CompleteRevocationRefs.cs
+++ b/crypto/src/asn1/esf/CompleteRevocationRefs.cs
@@ -14,69 +14,58 @@ namespace Org.BouncyCastle.Asn1.Esf
 	public class CompleteRevocationRefs
 		: Asn1Encodable
 	{
-		private readonly Asn1Sequence crlOcspRefs;
+		private readonly Asn1Sequence m_crlOcspRefs;
 
-		public static CompleteRevocationRefs GetInstance(
-			object obj)
+		public static CompleteRevocationRefs GetInstance(object obj)
 		{
-			if (obj == null || obj is CompleteRevocationRefs)
-				return (CompleteRevocationRefs) obj;
+			if (obj == null)
+				return null;
 
-			if (obj is Asn1Sequence)
-				return new CompleteRevocationRefs((Asn1Sequence) obj);
+			if (obj is CompleteRevocationRefs completeRevocationRefs)
+				return completeRevocationRefs;
 
-			throw new ArgumentException(
-				"Unknown object in 'CompleteRevocationRefs' factory: "
-                    + Platform.GetTypeName(obj),
-				"obj");
+			if (obj is Asn1Sequence asn1Sequence)
+				return new CompleteRevocationRefs(asn1Sequence);
+
+			throw new ArgumentException("Unknown object in 'CompleteRevocationRefs' factory: " + Platform.GetTypeName(obj),
+				nameof(obj));
 		}
 
-		private CompleteRevocationRefs(
-			Asn1Sequence seq)
+		private CompleteRevocationRefs(Asn1Sequence seq)
 		{
 			if (seq == null)
-				throw new ArgumentNullException("seq");
+				throw new ArgumentNullException(nameof(seq));
 
-			foreach (Asn1Encodable ae in seq)
-			{
-				CrlOcspRef.GetInstance(ae.ToAsn1Object());
-			}
+            // Validate
+            seq.MapElements(element => CrlOcspRef.GetInstance(element.ToAsn1Object()));
 
-			this.crlOcspRefs = seq;
+			m_crlOcspRefs = seq;
 		}
 
-		public CompleteRevocationRefs(
-			params CrlOcspRef[] crlOcspRefs)
+		public CompleteRevocationRefs(params CrlOcspRef[] crlOcspRefs)
 		{
 			if (crlOcspRefs == null)
-				throw new ArgumentNullException("crlOcspRefs");
+				throw new ArgumentNullException(nameof(crlOcspRefs));
 
-			this.crlOcspRefs = new DerSequence(crlOcspRefs);
+			m_crlOcspRefs = new DerSequence(crlOcspRefs);
 		}
 
-		public CompleteRevocationRefs(
-			IEnumerable<CrlOcspRef> crlOcspRefs)
+		public CompleteRevocationRefs(IEnumerable<CrlOcspRef> crlOcspRefs)
 		{
 			if (crlOcspRefs == null)
-				throw new ArgumentNullException("crlOcspRefs");
+                throw new ArgumentNullException(nameof(crlOcspRefs));
 
-			this.crlOcspRefs = new DerSequence(
-				Asn1EncodableVector.FromEnumerable(crlOcspRefs));
+            m_crlOcspRefs = new DerSequence(Asn1EncodableVector.FromEnumerable(crlOcspRefs));
 		}
 
 		public CrlOcspRef[] GetCrlOcspRefs()
 		{
-			CrlOcspRef[] result = new CrlOcspRef[crlOcspRefs.Count];
-			for (int i = 0; i < crlOcspRefs.Count; ++i)
-			{
-				result[i] = CrlOcspRef.GetInstance(crlOcspRefs[i].ToAsn1Object());
-			}
-			return result;
+            return m_crlOcspRefs.MapElements(element => CrlOcspRef.GetInstance(element.ToAsn1Object()));
 		}
 
 		public override Asn1Object ToAsn1Object()
 		{
-			return crlOcspRefs;
+			return m_crlOcspRefs;
 		}
 	}
 }
diff --git a/crypto/src/asn1/esf/CrlIdentifier.cs b/crypto/src/asn1/esf/CrlIdentifier.cs
index 54e930acc..29003260a 100644
--- a/crypto/src/asn1/esf/CrlIdentifier.cs
+++ b/crypto/src/asn1/esf/CrlIdentifier.cs
@@ -20,9 +20,9 @@ namespace Org.BouncyCastle.Asn1.Esf
 	public class CrlIdentifier
 		: Asn1Encodable
 	{
-		private readonly X509Name crlIssuer;
-		private readonly Asn1UtcTime crlIssuedTime;
-		private readonly DerInteger crlNumber;
+		private readonly X509Name m_crlIssuer;
+		private readonly Asn1UtcTime m_crlIssuedTime;
+		private readonly DerInteger m_crlNumber;
 
 		public static CrlIdentifier GetInstance(object obj)
 		{
@@ -46,15 +46,15 @@ namespace Org.BouncyCastle.Asn1.Esf
 			if (seq.Count < 2 || seq.Count > 3)
 				throw new ArgumentException("Bad sequence size: " + seq.Count, nameof(seq));
 
-			this.crlIssuer = X509Name.GetInstance(seq[0]);
-			this.crlIssuedTime = Asn1UtcTime.GetInstance(seq[1]);
+			this.m_crlIssuer = X509Name.GetInstance(seq[0]);
+			this.m_crlIssuedTime = Asn1UtcTime.GetInstance(seq[1]);
 
             // Validate crlIssuedTime is in the appropriate year range
-            crlIssuedTime.ToDateTime(2049);
+            m_crlIssuedTime.ToDateTime(2049);
 
 			if (seq.Count > 2)
 			{
-				this.crlNumber = DerInteger.GetInstance(seq[2]);
+				this.m_crlNumber = DerInteger.GetInstance(seq[2]);
 			}
 		}
 
@@ -75,37 +75,37 @@ namespace Org.BouncyCastle.Asn1.Esf
 
         public CrlIdentifier(X509Name crlIssuer, Asn1UtcTime crlIssuedTime, BigInteger crlNumber)
         {
-            this.crlIssuer = crlIssuer ?? throw new ArgumentNullException(nameof(crlIssuer));
-            this.crlIssuedTime = crlIssuedTime ?? throw new ArgumentNullException(nameof(crlIssuedTime));
+            m_crlIssuer = crlIssuer ?? throw new ArgumentNullException(nameof(crlIssuer));
+            m_crlIssuedTime = crlIssuedTime ?? throw new ArgumentNullException(nameof(crlIssuedTime));
 
             if (null != crlNumber)
             {
-                this.crlNumber = new DerInteger(crlNumber);
+                m_crlNumber = new DerInteger(crlNumber);
             }
 
             // Validate crlIssuedTime is in the appropriate year range
-            this.crlIssuedTime.ToDateTime(2049);
+            m_crlIssuedTime.ToDateTime(2049);
         }
 
         public X509Name CrlIssuer
 		{
-			get { return crlIssuer; }
+			get { return m_crlIssuer; }
 		}
 
 		public DateTime CrlIssuedTime
 		{
-			get { return crlIssuedTime.ToDateTime(2049); }
+			get { return m_crlIssuedTime.ToDateTime(2049); }
 		}
 
 		public BigInteger CrlNumber
 		{
-			get { return crlNumber?.Value; }
+			get { return m_crlNumber?.Value; }
 		}
 
 		public override Asn1Object ToAsn1Object()
 		{
-			var v = new Asn1EncodableVector(crlIssuer.ToAsn1Object(), crlIssuedTime);
-            v.AddOptional(crlNumber);
+			var v = new Asn1EncodableVector(m_crlIssuer.ToAsn1Object(), m_crlIssuedTime);
+            v.AddOptional(m_crlNumber);
 			return new DerSequence(v);
 		}
 	}
diff --git a/crypto/src/asn1/esf/CrlListID.cs b/crypto/src/asn1/esf/CrlListID.cs
index d3c4365c5..1ee58aebc 100644
--- a/crypto/src/asn1/esf/CrlListID.cs
+++ b/crypto/src/asn1/esf/CrlListID.cs
@@ -17,71 +17,60 @@ namespace Org.BouncyCastle.Asn1.Esf
 	public class CrlListID
 		: Asn1Encodable
 	{
-		private readonly Asn1Sequence crls;
+		private readonly Asn1Sequence m_crls;
 
-		public static CrlListID GetInstance(
-			object obj)
+		public static CrlListID GetInstance(object obj)
 		{
-			if (obj == null || obj is CrlListID)
-				return (CrlListID) obj;
+			if (obj == null)
+				return null;
 
-			if (obj is Asn1Sequence)
-				return new CrlListID((Asn1Sequence) obj);
+			if (obj is CrlListID crlListID)
+				return crlListID;
 
-			throw new ArgumentException(
-				"Unknown object in 'CrlListID' factory: "
-                    + Platform.GetTypeName(obj),
-				"obj");
+			if (obj is Asn1Sequence asn1Sequence)
+				return new CrlListID(asn1Sequence);
+
+			throw new ArgumentException("Unknown object in 'CrlListID' factory: " + Platform.GetTypeName(obj),
+				nameof(obj));
 		}
 
-		private CrlListID(
-			Asn1Sequence seq)
+		private CrlListID(Asn1Sequence seq)
 		{
 			if (seq == null)
-				throw new ArgumentNullException("seq");
+				throw new ArgumentNullException(nameof(seq));
 			if (seq.Count != 1)
-				throw new ArgumentException("Bad sequence size: " + seq.Count, "seq");
+				throw new ArgumentException("Bad sequence size: " + seq.Count, nameof(seq));
 
-			this.crls = (Asn1Sequence) seq[0].ToAsn1Object();
+			m_crls = (Asn1Sequence)seq[0].ToAsn1Object();
 
-			foreach (Asn1Encodable ae in this.crls)
-			{
-				CrlValidatedID.GetInstance(ae.ToAsn1Object());
-			}
+			// Validate
+			m_crls.MapElements(element => CrlValidatedID.GetInstance(element.ToAsn1Object()));
 		}
 
-		public CrlListID(
-			params CrlValidatedID[] crls)
+		public CrlListID(params CrlValidatedID[] crls)
 		{
 			if (crls == null)
-				throw new ArgumentNullException("crls");
+				throw new ArgumentNullException(nameof(crls));
 
-			this.crls = new DerSequence(crls);
+			this.m_crls = new DerSequence(crls);
 		}
 
-		public CrlListID(
-			IEnumerable<CrlValidatedID> crls)
+		public CrlListID(IEnumerable<CrlValidatedID> crls)
 		{
 			if (crls == null)
-				throw new ArgumentNullException("crls");
+                throw new ArgumentNullException(nameof(crls));
 
-			this.crls = new DerSequence(
-				Asn1EncodableVector.FromEnumerable(crls));
+            this.m_crls = new DerSequence(Asn1EncodableVector.FromEnumerable(crls));
 		}
 
 		public CrlValidatedID[] GetCrls()
 		{
-			CrlValidatedID[] result = new CrlValidatedID[crls.Count];
-			for (int i = 0; i < crls.Count; ++i)
-			{
-				result[i] = CrlValidatedID.GetInstance(crls[i].ToAsn1Object());
-			}
-			return result;
+            return m_crls.MapElements(element => CrlValidatedID.GetInstance(element.ToAsn1Object()));
 		}
 
 		public override Asn1Object ToAsn1Object()
 		{
-			return new DerSequence(crls);
+			return new DerSequence(m_crls);
 		}
 	}
 }
diff --git a/crypto/src/asn1/esf/OcspListID.cs b/crypto/src/asn1/esf/OcspListID.cs
index 3918dfd42..974962571 100644
--- a/crypto/src/asn1/esf/OcspListID.cs
+++ b/crypto/src/asn1/esf/OcspListID.cs
@@ -16,71 +16,60 @@ namespace Org.BouncyCastle.Asn1.Esf
 	public class OcspListID
 		: Asn1Encodable
 	{
-		private readonly Asn1Sequence ocspResponses;
+		private readonly Asn1Sequence m_ocspResponses;
 
-		public static OcspListID GetInstance(
-			object obj)
+		public static OcspListID GetInstance(object obj)
 		{
-			if (obj == null || obj is OcspListID)
-				return (OcspListID) obj;
+			if (obj == null)
+				return null;
 
-			if (obj is Asn1Sequence)
-				return new OcspListID((Asn1Sequence) obj);
+			if (obj is OcspListID ocspListID)
+				return ocspListID;
 
-			throw new ArgumentException(
-				"Unknown object in 'OcspListID' factory: "
-                    + Platform.GetTypeName(obj),
-				"obj");
+			if (obj is Asn1Sequence asn1Sequence)
+				return new OcspListID(asn1Sequence);
+
+			throw new ArgumentException("Unknown object in 'OcspListID' factory: " + Platform.GetTypeName(obj),
+				nameof(obj));
 		}
 
-		private OcspListID(
-			Asn1Sequence seq)
+		private OcspListID(Asn1Sequence seq)
 		{
 			if (seq == null)
-				throw new ArgumentNullException("seq");
+				throw new ArgumentNullException(nameof(seq));
 			if (seq.Count != 1)
-				throw new ArgumentException("Bad sequence size: " + seq.Count, "seq");
+				throw new ArgumentException("Bad sequence size: " + seq.Count, nameof(seq));
 
-			this.ocspResponses = (Asn1Sequence) seq[0].ToAsn1Object();
+			m_ocspResponses = (Asn1Sequence)seq[0].ToAsn1Object();
 
-			foreach (Asn1Encodable ae in this.ocspResponses)
-			{
-				OcspResponsesID.GetInstance(ae.ToAsn1Object());
-			}
+            // Validate
+            m_ocspResponses.MapElements(element => OcspResponsesID.GetInstance(element.ToAsn1Object()));
 		}
 
-		public OcspListID(
-			params OcspResponsesID[] ocspResponses)
+		public OcspListID(params OcspResponsesID[] ocspResponses)
 		{
 			if (ocspResponses == null)
-				throw new ArgumentNullException("ocspResponses");
+				throw new ArgumentNullException(nameof(ocspResponses));
 
-			this.ocspResponses = new DerSequence(ocspResponses);
+			m_ocspResponses = new DerSequence(ocspResponses);
 		}
 
-		public OcspListID(
-			IEnumerable<OcspResponsesID> ocspResponses)
+		public OcspListID(IEnumerable<OcspResponsesID> ocspResponses)
 		{
 			if (ocspResponses == null)
-				throw new ArgumentNullException("ocspResponses");
+                throw new ArgumentNullException(nameof(ocspResponses));
 
-			this.ocspResponses = new DerSequence(
-				Asn1EncodableVector.FromEnumerable(ocspResponses));
+            m_ocspResponses = new DerSequence(Asn1EncodableVector.FromEnumerable(ocspResponses));
 		}
 
 		public OcspResponsesID[] GetOcspResponses()
 		{
-			OcspResponsesID[] result = new OcspResponsesID[ocspResponses.Count];
-			for (int i = 0; i < ocspResponses.Count; ++i)
-			{
-				result[i] = OcspResponsesID.GetInstance(ocspResponses[i].ToAsn1Object());
-			}
-			return result;
+            return m_ocspResponses.MapElements(element => OcspResponsesID.GetInstance(element.ToAsn1Object()));
 		}
 
 		public override Asn1Object ToAsn1Object()
 		{
-			return new DerSequence(ocspResponses);
+			return new DerSequence(m_ocspResponses);
 		}
 	}
 }
diff --git a/crypto/src/asn1/esf/OtherSigningCertificate.cs b/crypto/src/asn1/esf/OtherSigningCertificate.cs
index a4f4a0727..aa1dcbf99 100644
--- a/crypto/src/asn1/esf/OtherSigningCertificate.cs
+++ b/crypto/src/asn1/esf/OtherSigningCertificate.cs
@@ -17,111 +17,89 @@ namespace Org.BouncyCastle.Asn1.Esf
 	public class OtherSigningCertificate
 		: Asn1Encodable
 	{
-		private readonly Asn1Sequence	certs;
-		private readonly Asn1Sequence	policies;
+		private readonly Asn1Sequence m_certs;
+		private readonly Asn1Sequence m_policies;
 
-		public static OtherSigningCertificate GetInstance(
-			object obj)
+		public static OtherSigningCertificate GetInstance(object obj)
 		{
-			if (obj == null || obj is OtherSigningCertificate)
-				return (OtherSigningCertificate) obj;
+			if (obj == null)
+				return null;
+
+			if (obj is OtherSigningCertificate otherSigningCertificate)
+				return otherSigningCertificate;
 
-			if (obj is Asn1Sequence)
-				return new OtherSigningCertificate((Asn1Sequence) obj);
+			if (obj is Asn1Sequence asn1Sequence)
+				return new OtherSigningCertificate(asn1Sequence);
 
-			throw new ArgumentException(
-				"Unknown object in 'OtherSigningCertificate' factory: "
-                    + Platform.GetTypeName(obj),
-				"obj");
+			throw new ArgumentException("Unknown object in 'OtherSigningCertificate' factory: " + Platform.GetTypeName(obj),
+				nameof(obj));
 		}
 
-		private OtherSigningCertificate(
-			Asn1Sequence seq)
+		private OtherSigningCertificate(Asn1Sequence seq)
 		{
 			if (seq == null)
-				throw new ArgumentNullException("seq");
+				throw new ArgumentNullException(nameof(seq));
 			if (seq.Count < 1 || seq.Count > 2)
-				throw new ArgumentException("Bad sequence size: " + seq.Count, "seq");
+				throw new ArgumentException("Bad sequence size: " + seq.Count, nameof(seq));
 
-			this.certs = Asn1Sequence.GetInstance(seq[0].ToAsn1Object());
+			m_certs = Asn1Sequence.GetInstance(seq[0].ToAsn1Object());
 
 			if (seq.Count > 1)
 			{
-				this.policies = Asn1Sequence.GetInstance(seq[1].ToAsn1Object());
+				m_policies = Asn1Sequence.GetInstance(seq[1].ToAsn1Object());
 			}
 		}
 
-		public OtherSigningCertificate(
-			params OtherCertID[] certs)
+		public OtherSigningCertificate(params OtherCertID[] certs)
 			: this(certs, null)
 		{
 		}
 
-		public OtherSigningCertificate(
-			OtherCertID[]				certs,
-			params PolicyInformation[]	policies)
+		public OtherSigningCertificate(OtherCertID[] certs, params PolicyInformation[] policies)
 		{
 			if (certs == null)
-				throw new ArgumentNullException("certs");
+                throw new ArgumentNullException(nameof(certs));
 
-			this.certs = new DerSequence(certs);
+            m_certs = new DerSequence(certs);
 
 			if (policies != null)
 			{
-				this.policies = new DerSequence(policies);
+				m_policies = new DerSequence(policies);
 			}
 		}
 
-		public OtherSigningCertificate(
-			IEnumerable<OtherCertID> certs)
+		public OtherSigningCertificate(IEnumerable<OtherCertID> certs)
 			: this(certs, null)
 		{
 		}
 
-		public OtherSigningCertificate(
-			IEnumerable<OtherCertID> certs,
-			IEnumerable<PolicyInformation> policies)
+		public OtherSigningCertificate(IEnumerable<OtherCertID> certs, IEnumerable<PolicyInformation> policies)
 		{
 			if (certs == null)
-				throw new ArgumentNullException("certs");
+                throw new ArgumentNullException(nameof(certs));
 
-			this.certs = new DerSequence(
-				Asn1EncodableVector.FromEnumerable(certs));
+            m_certs = new DerSequence(Asn1EncodableVector.FromEnumerable(certs));
 
 			if (policies != null)
 			{
-				this.policies = new DerSequence(
-					Asn1EncodableVector.FromEnumerable(policies));
+				m_policies = new DerSequence(Asn1EncodableVector.FromEnumerable(policies));
 			}
 		}
 
 		public OtherCertID[] GetCerts()
 		{
-			OtherCertID[] cs = new OtherCertID[certs.Count];
-			for (int i = 0; i < certs.Count; ++i)
-			{
-				cs[i] = OtherCertID.GetInstance(certs[i].ToAsn1Object());
-			}
-			return cs;
+			return m_certs.MapElements(element => OtherCertID.GetInstance(element.ToAsn1Object()));
 		}
 
 		public PolicyInformation[] GetPolicies()
 		{
-			if (policies == null)
-				return null;
-
-			PolicyInformation[] ps = new PolicyInformation[policies.Count];
-			for (int i = 0; i < policies.Count; ++i)
-			{
-				ps[i] = PolicyInformation.GetInstance(policies[i].ToAsn1Object());
-			}
-			return ps;
+            return m_policies?.MapElements(element => PolicyInformation.GetInstance(element.ToAsn1Object()));
 		}
 
 		public override Asn1Object ToAsn1Object()
 		{
-			Asn1EncodableVector v = new Asn1EncodableVector(certs);
-            v.AddOptional(policies);
+			Asn1EncodableVector v = new Asn1EncodableVector(m_certs);
+            v.AddOptional(m_policies);
 			return new DerSequence(v);
 		}
 	}
diff --git a/crypto/src/asn1/esf/RevocationValues.cs b/crypto/src/asn1/esf/RevocationValues.cs
index 682728dde..61bfd0be1 100644
--- a/crypto/src/asn1/esf/RevocationValues.cs
+++ b/crypto/src/asn1/esf/RevocationValues.cs
@@ -19,129 +19,113 @@ namespace Org.BouncyCastle.Asn1.Esf
 	public class RevocationValues
 		: Asn1Encodable
 	{
-		private readonly Asn1Sequence	crlVals;
-		private readonly Asn1Sequence	ocspVals;
-		private readonly OtherRevVals	otherRevVals;
+		private readonly Asn1Sequence m_crlVals;
+		private readonly Asn1Sequence m_ocspVals;
+		private readonly OtherRevVals m_otherRevVals;
 
-		public static RevocationValues GetInstance(
-			object obj)
+		public static RevocationValues GetInstance(object obj)
 		{
-			if (obj == null || obj is RevocationValues)
-				return (RevocationValues) obj;
+            if (obj == null)
+                return null;
+
+            if (obj is RevocationValues revocationValues)
+				return revocationValues;
 
 			return new RevocationValues(Asn1Sequence.GetInstance(obj));
 		}
 
-		private RevocationValues(
-			Asn1Sequence seq)
+		private RevocationValues(Asn1Sequence seq)
 		{
 			if (seq == null)
-				throw new ArgumentNullException("seq");
+				throw new ArgumentNullException(nameof(seq));
 			if (seq.Count > 3)
-				throw new ArgumentException("Bad sequence size: " + seq.Count, "seq");
+				throw new ArgumentException("Bad sequence size: " + seq.Count, nameof(seq));
 
 			foreach (Asn1TaggedObject taggedObj in seq)
 			{
 				Asn1Object asn1Obj = taggedObj.GetObject();
 				switch (taggedObj.TagNo)
 				{
-					case 0:
-						Asn1Sequence crlValsSeq = (Asn1Sequence) asn1Obj;
-						foreach (Asn1Encodable ae in crlValsSeq)
-						{
-							CertificateList.GetInstance(ae.ToAsn1Object());
-						}
-						this.crlVals = crlValsSeq;
-						break;
-					case 1:
-						Asn1Sequence ocspValsSeq = (Asn1Sequence) asn1Obj;
-						foreach (Asn1Encodable ae in ocspValsSeq)
-						{
-							BasicOcspResponse.GetInstance(ae.ToAsn1Object());
-						}
-						this.ocspVals = ocspValsSeq;
-						break;
-					case 2:
-						this.otherRevVals = OtherRevVals.GetInstance(asn1Obj);
-						break;
-					default:
-						throw new ArgumentException("Illegal tag in RevocationValues", "seq");
+				case 0:
+					Asn1Sequence crlValsSeq = (Asn1Sequence)asn1Obj;
+
+					// Validate
+					crlValsSeq.MapElements(element => CertificateList.GetInstance(element.ToAsn1Object()));
+
+					m_crlVals = crlValsSeq;
+					break;
+				case 1:
+					Asn1Sequence ocspValsSeq = (Asn1Sequence)asn1Obj;
+
+					// Validate
+					ocspValsSeq.MapElements(element => BasicOcspResponse.GetInstance(element.ToAsn1Object()));
+
+					m_ocspVals = ocspValsSeq;
+					break;
+				case 2:
+					m_otherRevVals = OtherRevVals.GetInstance(asn1Obj);
+					break;
+				default:
+					throw new ArgumentException("Illegal tag in RevocationValues", nameof(seq));
 				}
 			}
 		}
 
-		public RevocationValues(
-			CertificateList[]	crlVals,
-			BasicOcspResponse[]	ocspVals,
-			OtherRevVals		otherRevVals)
+		public RevocationValues(CertificateList[] crlVals, BasicOcspResponse[] ocspVals, OtherRevVals otherRevVals)
 		{
 			if (crlVals != null)
 			{
-				this.crlVals = new DerSequence(crlVals);
+				m_crlVals = new DerSequence(crlVals);
 			}
 
 			if (ocspVals != null)
 			{
-				this.ocspVals = new DerSequence(ocspVals);
+				m_ocspVals = new DerSequence(ocspVals);
 			}
 
-			this.otherRevVals = otherRevVals;
+			m_otherRevVals = otherRevVals;
 		}
 
-		public RevocationValues(
-			IEnumerable<CertificateList> crlVals,
-			IEnumerable<BasicOcspResponse> ocspVals,
+		public RevocationValues(IEnumerable<CertificateList> crlVals, IEnumerable<BasicOcspResponse> ocspVals,
 			OtherRevVals otherRevVals)
 		{
 			if (crlVals != null)
 			{
-				this.crlVals = new DerSequence(
-					Asn1EncodableVector.FromEnumerable(crlVals));
+				m_crlVals = new DerSequence(Asn1EncodableVector.FromEnumerable(crlVals));
 			}
 
 			if (ocspVals != null)
 			{
-				this.ocspVals = new DerSequence(
-					Asn1EncodableVector.FromEnumerable(ocspVals));
+				m_ocspVals = new DerSequence(Asn1EncodableVector.FromEnumerable(ocspVals));
 			}
 
-			this.otherRevVals = otherRevVals;
+			m_otherRevVals = otherRevVals;
 		}
 
 		public CertificateList[] GetCrlVals()
 		{
-			CertificateList[] result = new CertificateList[crlVals.Count];
-			for (int i = 0; i < crlVals.Count; ++i)
-			{
-				result[i] = CertificateList.GetInstance(crlVals[i].ToAsn1Object());
-			}
-			return result;
+			return m_crlVals.MapElements(element => CertificateList.GetInstance(element.ToAsn1Object()));
 		}
 
 		public BasicOcspResponse[] GetOcspVals()
 		{
-			BasicOcspResponse[] result = new BasicOcspResponse[ocspVals.Count];
-			for (int i = 0; i < ocspVals.Count; ++i)
-			{
-				result[i] = BasicOcspResponse.GetInstance(ocspVals[i].ToAsn1Object());
-			}
-			return result;
+            return m_ocspVals.MapElements(element => BasicOcspResponse.GetInstance(element.ToAsn1Object()));
 		}
 
 		public OtherRevVals OtherRevVals
 		{
-			get { return otherRevVals; }
+			get { return m_otherRevVals; }
 		}
 
 		public override Asn1Object ToAsn1Object()
 		{
 			Asn1EncodableVector v = new Asn1EncodableVector();
-            v.AddOptionalTagged(true, 0, crlVals);
-            v.AddOptionalTagged(true, 1, ocspVals);
+            v.AddOptionalTagged(true, 0, m_crlVals);
+            v.AddOptionalTagged(true, 1, m_ocspVals);
 
-            if (otherRevVals != null)
+            if (m_otherRevVals != null)
 			{
-				v.Add(new DerTaggedObject(true, 2, otherRevVals.ToAsn1Object()));
+				v.Add(new DerTaggedObject(true, 2, m_otherRevVals.ToAsn1Object()));
 			}
 
             return new DerSequence(v);
diff --git a/crypto/src/asn1/esf/SignaturePolicyId.cs b/crypto/src/asn1/esf/SignaturePolicyId.cs
index 21bb40560..84e9f8c62 100644
--- a/crypto/src/asn1/esf/SignaturePolicyId.cs
+++ b/crypto/src/asn1/esf/SignaturePolicyId.cs
@@ -21,119 +21,103 @@ namespace Org.BouncyCastle.Asn1.Esf
 	public class SignaturePolicyId
 		: Asn1Encodable
 	{
-		private readonly DerObjectIdentifier	sigPolicyIdentifier;
-		private readonly OtherHashAlgAndValue	sigPolicyHash;
-		private readonly Asn1Sequence			sigPolicyQualifiers;
+		private readonly DerObjectIdentifier m_sigPolicyIdentifier;
+		private readonly OtherHashAlgAndValue m_sigPolicyHash;
+		private readonly Asn1Sequence m_sigPolicyQualifiers;
 
-		public static SignaturePolicyId GetInstance(
-			object obj)
+		public static SignaturePolicyId GetInstance(object obj)
 		{
-			if (obj == null || obj is SignaturePolicyId)
-				return (SignaturePolicyId) obj;
+			if (obj == null)
+				return null;
+
+			if (obj is SignaturePolicyId signaturePolicyId)
+				return signaturePolicyId;
 
-			if (obj is Asn1Sequence)
-				return new SignaturePolicyId((Asn1Sequence) obj);
+			if (obj is Asn1Sequence asn1Sequence)
+				return new SignaturePolicyId(asn1Sequence);
 
-			throw new ArgumentException(
-				"Unknown object in 'SignaturePolicyId' factory: "
-                    + Platform.GetTypeName(obj),
-				"obj");
+			throw new ArgumentException("Unknown object in 'SignaturePolicyId' factory: " + Platform.GetTypeName(obj),
+				nameof(obj));
 		}
 
-		private SignaturePolicyId(
-			Asn1Sequence seq)
+		private SignaturePolicyId(Asn1Sequence seq)
 		{
 			if (seq == null)
-				throw new ArgumentNullException("seq");
+				throw new ArgumentNullException(nameof(seq));
 			if (seq.Count < 2 || seq.Count > 3)
-				throw new ArgumentException("Bad sequence size: " + seq.Count, "seq");
+				throw new ArgumentException("Bad sequence size: " + seq.Count, nameof(seq));
 
-			this.sigPolicyIdentifier = (DerObjectIdentifier) seq[0].ToAsn1Object();
-			this.sigPolicyHash = OtherHashAlgAndValue.GetInstance(seq[1].ToAsn1Object());
+			m_sigPolicyIdentifier = (DerObjectIdentifier)seq[0].ToAsn1Object();
+			m_sigPolicyHash = OtherHashAlgAndValue.GetInstance(seq[1].ToAsn1Object());
 
 			if (seq.Count > 2)
 			{
-				this.sigPolicyQualifiers = (Asn1Sequence) seq[2].ToAsn1Object();
+				m_sigPolicyQualifiers = (Asn1Sequence)seq[2].ToAsn1Object();
 			}
 		}
 
-		public SignaturePolicyId(
-			DerObjectIdentifier		sigPolicyIdentifier,
-			OtherHashAlgAndValue	sigPolicyHash)
+		public SignaturePolicyId(DerObjectIdentifier sigPolicyIdentifier, OtherHashAlgAndValue sigPolicyHash)
 			: this(sigPolicyIdentifier, sigPolicyHash, null)
 		{
 		}
 
-		public SignaturePolicyId(
-			DerObjectIdentifier				sigPolicyIdentifier,
-			OtherHashAlgAndValue			sigPolicyHash,
+		public SignaturePolicyId(DerObjectIdentifier sigPolicyIdentifier, OtherHashAlgAndValue sigPolicyHash,
 			params SigPolicyQualifierInfo[]	sigPolicyQualifiers)
 		{
 			if (sigPolicyIdentifier == null)
-				throw new ArgumentNullException("sigPolicyIdentifier");
+				throw new ArgumentNullException(nameof(sigPolicyIdentifier));
 			if (sigPolicyHash == null)
-				throw new ArgumentNullException("sigPolicyHash");
+				throw new ArgumentNullException(nameof(sigPolicyHash));
 
-			this.sigPolicyIdentifier = sigPolicyIdentifier;
-			this.sigPolicyHash = sigPolicyHash;
+			m_sigPolicyIdentifier = sigPolicyIdentifier;
+			m_sigPolicyHash = sigPolicyHash;
 
 			if (sigPolicyQualifiers != null)
 			{
-				this.sigPolicyQualifiers = new DerSequence(sigPolicyQualifiers);
+				m_sigPolicyQualifiers = new DerSequence(sigPolicyQualifiers);
 			}
 		}
 
-		public SignaturePolicyId(
-			DerObjectIdentifier sigPolicyIdentifier,
-			OtherHashAlgAndValue sigPolicyHash,
+		public SignaturePolicyId(DerObjectIdentifier sigPolicyIdentifier, OtherHashAlgAndValue sigPolicyHash,
 			IEnumerable<SigPolicyQualifierInfo> sigPolicyQualifiers)
 		{
-			if (sigPolicyIdentifier == null)
-				throw new ArgumentNullException("sigPolicyIdentifier");
-			if (sigPolicyHash == null)
-				throw new ArgumentNullException("sigPolicyHash");
+            if (sigPolicyIdentifier == null)
+                throw new ArgumentNullException(nameof(sigPolicyIdentifier));
+            if (sigPolicyHash == null)
+                throw new ArgumentNullException(nameof(sigPolicyHash));
 
-			this.sigPolicyIdentifier = sigPolicyIdentifier;
-			this.sigPolicyHash = sigPolicyHash;
+			m_sigPolicyIdentifier = sigPolicyIdentifier;
+			m_sigPolicyHash = sigPolicyHash;
 
 			if (sigPolicyQualifiers != null)
 			{
-				this.sigPolicyQualifiers = new DerSequence(
-					Asn1EncodableVector.FromEnumerable(sigPolicyQualifiers));
+				m_sigPolicyQualifiers = new DerSequence(Asn1EncodableVector.FromEnumerable(sigPolicyQualifiers));
 			}
 		}
 
 		public DerObjectIdentifier SigPolicyIdentifier
 		{
-			get { return sigPolicyIdentifier; }
+			get { return m_sigPolicyIdentifier; }
 		}
 
 		public OtherHashAlgAndValue SigPolicyHash
 		{
-			get { return sigPolicyHash; }
+			get { return m_sigPolicyHash; }
 		}
 
 		public SigPolicyQualifierInfo[] GetSigPolicyQualifiers()
 		{
-			if (sigPolicyQualifiers == null)
-				return null;
-
-			SigPolicyQualifierInfo[] infos = new SigPolicyQualifierInfo[sigPolicyQualifiers.Count];
-			for (int i = 0; i < sigPolicyQualifiers.Count; ++i)
-			{
-				infos[i] = SigPolicyQualifierInfo.GetInstance(sigPolicyQualifiers[i]);
-			}
-			return infos;
+			return m_sigPolicyQualifiers?.MapElements(SigPolicyQualifierInfo.GetInstance);
 		}
 
 		public override Asn1Object ToAsn1Object()
 		{
 			Asn1EncodableVector v = new Asn1EncodableVector(
-				sigPolicyIdentifier, sigPolicyHash.ToAsn1Object());
+				m_sigPolicyIdentifier, m_sigPolicyHash.ToAsn1Object());
 
-			if (sigPolicyQualifiers != null)
+			if (m_sigPolicyQualifiers != null)
 			{
-				v.Add(sigPolicyQualifiers.ToAsn1Object());
+				v.Add(m_sigPolicyQualifiers.ToAsn1Object());
 			}
 
 			return new DerSequence(v);
diff --git a/crypto/src/asn1/isismtt/x509/DeclarationOfMajority.cs b/crypto/src/asn1/isismtt/x509/DeclarationOfMajority.cs
index c9c96cbda..471776630 100644
--- a/crypto/src/asn1/isismtt/x509/DeclarationOfMajority.cs
+++ b/crypto/src/asn1/isismtt/x509/DeclarationOfMajority.cs
@@ -33,20 +33,17 @@ namespace Org.BouncyCastle.Asn1.IsisMtt.X509
 			DateOfBirth = 2
 		};
 
-		private readonly Asn1TaggedObject declaration;
+		private readonly Asn1TaggedObject m_declaration;
 
-		public DeclarationOfMajority(
-			int notYoungerThan)
+		public DeclarationOfMajority(int notYoungerThan)
 		{
-			declaration = new DerTaggedObject(false, 0, new DerInteger(notYoungerThan));
+			m_declaration = new DerTaggedObject(false, 0, new DerInteger(notYoungerThan));
 		}
 
-		public DeclarationOfMajority(
-			bool	fullAge,
-			string	country)
+		public DeclarationOfMajority(bool fullAge, string country)
 		{
 			if (country.Length > 2)
-				throw new ArgumentException("country can only be 2 characters");
+				throw new ArgumentException("country can only be 2 characters", nameof(country));
 
 			DerPrintableString countryString = new DerPrintableString(country, true);
 
@@ -60,38 +57,34 @@ namespace Org.BouncyCastle.Asn1.IsisMtt.X509
 				seq = new DerSequence(DerBoolean.False, countryString);
 			}
 
-			this.declaration = new DerTaggedObject(false, 1, seq);
+			m_declaration = new DerTaggedObject(false, 1, seq);
 		}
 
-		public DeclarationOfMajority(
-            Asn1GeneralizedTime dateOfBirth)
+		public DeclarationOfMajority(Asn1GeneralizedTime dateOfBirth)
 		{
-			this.declaration = new DerTaggedObject(false, 2, dateOfBirth);
+			m_declaration = new DerTaggedObject(false, 2, dateOfBirth);
 		}
 
-		public static DeclarationOfMajority GetInstance(
-			object obj)
+		public static DeclarationOfMajority GetInstance(object obj)
 		{
-			if (obj == null || obj is DeclarationOfMajority)
-			{
-				return (DeclarationOfMajority) obj;
-			}
+			if (obj == null)
+				return null;
 
-			if (obj is Asn1TaggedObject)
-			{
-				return new DeclarationOfMajority((Asn1TaggedObject) obj);
-			}
+			if (obj is DeclarationOfMajority declarationOfMajority)
+				return declarationOfMajority;
+
+			if (obj is Asn1TaggedObject asn1TaggedObject)
+				return new DeclarationOfMajority(asn1TaggedObject);
 
-            throw new ArgumentException("unknown object in factory: " + Platform.GetTypeName(obj), "obj");
+            throw new ArgumentException("unknown object in factory: " + Platform.GetTypeName(obj), nameof(obj));
 		}
 
-		private DeclarationOfMajority(
-			Asn1TaggedObject o)
+		private DeclarationOfMajority(Asn1TaggedObject o)
 		{
 			if (o.TagNo > 2)
 				throw new ArgumentException("Bad tag number: " + o.TagNo);
 
-			this.declaration = o;
+			m_declaration = o;
 		}
 
 		/**
@@ -116,12 +109,12 @@ namespace Org.BouncyCastle.Asn1.IsisMtt.X509
 		*/
 		public override Asn1Object ToAsn1Object()
 		{
-			return declaration;
+			return m_declaration;
 		}
 
 		public Choice Type
 		{
-			get { return (Choice) declaration.TagNo; }
+			get { return (Choice)m_declaration.TagNo; }
 		}
 
 		/**
@@ -131,12 +124,12 @@ namespace Org.BouncyCastle.Asn1.IsisMtt.X509
 		{
 			get
 			{
-				switch ((Choice) declaration.TagNo)
+				switch (Type)
 				{
-					case Choice.NotYoungerThan:
-                        return DerInteger.GetInstance(declaration, false).IntValueExact;
-					default:
-						return -1;
+				case Choice.NotYoungerThan:
+                    return DerInteger.GetInstance(m_declaration, false).IntValueExact;
+				default:
+					return -1;
 				}
 			}
 		}
@@ -145,12 +138,12 @@ namespace Org.BouncyCastle.Asn1.IsisMtt.X509
 		{
 			get
 			{
-				switch ((Choice) declaration.TagNo)
+				switch (Type)
 				{
-					case Choice.FullAgeAtCountry:
-						return Asn1Sequence.GetInstance(declaration, false);
-					default:
-						return null;
+				case Choice.FullAgeAtCountry:
+					return Asn1Sequence.GetInstance(m_declaration, false);
+				default:
+					return null;
 				}
 			}
 		}
@@ -159,12 +152,12 @@ namespace Org.BouncyCastle.Asn1.IsisMtt.X509
 		{
 			get
 			{
-				switch ((Choice) declaration.TagNo)
+				switch (Type)
 				{
-					case Choice.DateOfBirth:
-						return Asn1GeneralizedTime.GetInstance(declaration, false);
-					default:
-						return null;
+				case Choice.DateOfBirth:
+					return Asn1GeneralizedTime.GetInstance(m_declaration, false);
+				default:
+					return null;
 				}
 			}
 		}
diff --git a/crypto/src/asn1/tsp/TSTInfo.cs b/crypto/src/asn1/tsp/TSTInfo.cs
index dde11494c..c37208d3c 100644
--- a/crypto/src/asn1/tsp/TSTInfo.cs
+++ b/crypto/src/asn1/tsp/TSTInfo.cs
@@ -64,14 +64,14 @@ namespace Org.BouncyCastle.Asn1.Tsp
 
 					switch (tagged.TagNo)
 					{
-						case 0:
-							tsa = GeneralName.GetInstance(tagged, true);
-							break;
-						case 1:
-							extensions = X509Extensions.GetInstance(tagged, false);
-							break;
-						default:
-							throw new ArgumentException("Unknown tag value " + tagged.TagNo);
+					case 0:
+						tsa = GeneralName.GetInstance(tagged, true);
+						break;
+					case 1:
+						extensions = X509Extensions.GetInstance(tagged, false);
+						break;
+					default:
+						throw new ArgumentException("Unknown tag value " + tagged.TagNo);
 					}
 				}
 
diff --git a/crypto/src/asn1/x509/Time.cs b/crypto/src/asn1/x509/Time.cs
index e03055f6d..f7746257c 100644
--- a/crypto/src/asn1/x509/Time.cs
+++ b/crypto/src/asn1/x509/Time.cs
@@ -31,7 +31,7 @@ namespace Org.BouncyCastle.Asn1.X509
 
         public Time(Asn1GeneralizedTime generalizedTime)
         {
-            this.m_timeObject = generalizedTime ?? throw new ArgumentNullException(nameof(generalizedTime));
+            m_timeObject = generalizedTime ?? throw new ArgumentNullException(nameof(generalizedTime));
         }
 
         public Time(Asn1UtcTime utcTime)
@@ -42,7 +42,7 @@ namespace Org.BouncyCastle.Asn1.X509
             // Validate utcTime is in the appropriate year range
             utcTime.ToDateTime(2049);
 
-            this.m_timeObject = utcTime;
+            m_timeObject = utcTime;
         }
 
         /**