1 files changed, 62 insertions, 0 deletions
diff --git a/crypto/src/tls/KeyShareEntry.cs b/crypto/src/tls/KeyShareEntry.cs
new file mode 100644
index 000000000..c4be657c0
--- /dev/null
+++ b/crypto/src/tls/KeyShareEntry.cs
@@ -0,0 +1,62 @@
+using System;
+using System.IO;
+
+namespace Org.BouncyCastle.Tls
+{
+    public sealed class KeyShareEntry
+    {
+        private static bool CheckKeyExchangeLength(int length)
+        {
+            return 0 < length && length < (1 << 16);
+        }
+
+        private readonly int m_namedGroup;
+        private readonly byte[] m_keyExchange;
+
+        /// <param name="namedGroup"><see cref="NamedGroup"/></param>
+        /// <param name="keyExchange"></param>
+        public KeyShareEntry(int namedGroup, byte[] keyExchange)
+        {
+            if (!TlsUtilities.IsValidUint16(namedGroup))
+                throw new ArgumentException("should be a uint16", "namedGroup");
+            if (null == keyExchange)
+                throw new ArgumentNullException("keyExchange");
+            if (!CheckKeyExchangeLength(keyExchange.Length))
+                throw new ArgumentException("must have length from 1 to (2^16 - 1)", "keyExchange");
+
+            this.m_namedGroup = namedGroup;
+            this.m_keyExchange = keyExchange;
+        }
+
+        /// <returns><see cref="NamedGroup"/></returns>
+        public int NamedGroup
+        {
+            get { return m_namedGroup; }
+        }
+
+        public byte[] KeyExchange
+        {
+            get { return m_keyExchange; }
+        }
+
+        /// <summary>Encode this <see cref="KeyShareEntry"/> to a <see cref="Stream"/>.</summary>
+        /// <param name="output">the <see cref="Stream"/> to encode to.</param>
+        /// <exception cref="IOException"/>
+        public void Encode(Stream output)
+        {
+            TlsUtilities.WriteUint16(NamedGroup, output);
+            TlsUtilities.WriteOpaque16(KeyExchange, output);
+        }
+
+        /// <summary>Parse a <see cref="KeyShareEntry"/> from a <see cref="Stream"/>.</summary>
+        /// <param name="input">the <see cref="Stream"/> to parse from.</param>
+        /// <returns>a <see cref="KeyShareEntry"/> object.</returns>
+        /// <exception cref="IOException"/>
+        public static KeyShareEntry Parse(Stream input)
+        {
+            int namedGroup = TlsUtilities.ReadUint16(input);
+            byte[] keyExchange = TlsUtilities.ReadOpaque16(input, 1);
+            return new KeyShareEntry(namedGroup, keyExchange);
+        }
+    }
+}