1 files changed, 64 insertions, 0 deletions
diff --git a/crypto/src/util/collections/UnmodifiableDictionary.cs b/crypto/src/util/collections/UnmodifiableDictionary.cs
new file mode 100644
index 000000000..0bdf70ad7
--- /dev/null
+++ b/crypto/src/util/collections/UnmodifiableDictionary.cs
@@ -0,0 +1,64 @@
+using System;
+using System.Collections;
+
+namespace Org.BouncyCastle.Utilities.Collections
+{
+	public abstract class UnmodifiableDictionary
+		: IDictionary
+	{
+		protected UnmodifiableDictionary()
+		{
+		}
+
+		public virtual void Add(object k, object v)
+		{
+			throw new NotSupportedException();
+		}
+
+		public virtual void Clear()
+		{
+			throw new NotSupportedException();
+		}
+
+		public abstract bool Contains(object k);
+
+		public abstract void CopyTo(Array array, int index);
+
+		public abstract int Count { get; }
+
+		IEnumerator IEnumerable.GetEnumerator()
+		{
+			return GetEnumerator();
+		}
+
+		public abstract IDictionaryEnumerator GetEnumerator();
+
+		public virtual void Remove(object k)
+		{
+			throw new NotSupportedException();
+		}
+
+		public abstract bool IsFixedSize { get; }
+
+		public virtual bool IsReadOnly
+		{
+			get { return true; }
+		}
+
+		public abstract bool IsSynchronized { get; }
+
+		public abstract object SyncRoot { get; }
+
+		public abstract ICollection Keys { get; }
+
+		public abstract ICollection Values { get; }
+
+		public virtual object this[object k]
+		{
+			get { return GetValue(k); }
+			set { throw new NotSupportedException(); }
+		}
+
+		protected abstract object GetValue(object k);
+	}
+}