1 files changed, 77 insertions, 0 deletions
diff --git a/crypto/src/bcpg/AeadEncDataPacket.cs b/crypto/src/bcpg/AeadEncDataPacket.cs
new file mode 100644
index 000000000..2c7ec97f6
--- /dev/null
+++ b/crypto/src/bcpg/AeadEncDataPacket.cs
@@ -0,0 +1,77 @@
+using System;
+
+using Org.BouncyCastle.Utilities;
+using Org.BouncyCastle.Utilities.IO;
+
+namespace Org.BouncyCastle.Bcpg
+{
+    /**
+     * Packet representing AEAD encrypted data. At the moment this appears to exist in the following
+     * expired draft only, but it's appearing despite this.
+     *
+     * @ref https://datatracker.ietf.org/doc/html/draft-ietf-openpgp-rfc4880bis-04#section-5.16
+     */
+    public class AeadEncDataPacket
+        : InputStreamPacket
+    {
+        private readonly byte m_version;
+        private readonly SymmetricKeyAlgorithmTag m_algorithm;
+        private readonly AeadAlgorithmTag m_aeadAlgorithm;
+        private readonly byte m_chunkSize;
+        private readonly byte[] m_iv;
+
+        public AeadEncDataPacket(BcpgInputStream bcpgIn)
+            : base(bcpgIn)
+        {
+            m_version = (byte)bcpgIn.ReadByte();
+            if (m_version != 1)
+                throw new ArgumentException("wrong AEAD packet version: " + m_version);
+
+            m_algorithm = (SymmetricKeyAlgorithmTag)bcpgIn.ReadByte();
+            m_aeadAlgorithm = (AeadAlgorithmTag)bcpgIn.ReadByte();
+            m_chunkSize = (byte)bcpgIn.ReadByte();
+
+            m_iv = new byte[GetIVLength(m_aeadAlgorithm)];
+            bcpgIn.ReadFully(m_iv);
+        }
+
+        public AeadEncDataPacket(SymmetricKeyAlgorithmTag algorithm, AeadAlgorithmTag aeadAlgorithm, int chunkSize,
+            byte[] iv)
+            : base(null)
+        {
+            m_version = 1;
+            m_algorithm = algorithm;
+            m_aeadAlgorithm = aeadAlgorithm;
+            m_chunkSize = (byte)chunkSize;
+            m_iv = Arrays.Clone(iv);
+        }
+
+        public byte Version => m_version;
+
+        public SymmetricKeyAlgorithmTag Algorithm => m_algorithm;
+
+        public AeadAlgorithmTag AeadAlgorithm => m_aeadAlgorithm;
+
+        public int ChunkSize => m_chunkSize;
+
+        public byte[] GetIV()
+        {
+            return m_iv;
+        }
+
+        public static int GetIVLength(AeadAlgorithmTag aeadAlgorithm)
+        {
+            switch (aeadAlgorithm)
+            {
+            case AeadAlgorithmTag.Eax:
+                return 16;
+            case AeadAlgorithmTag.Ocb:
+                return 15;
+            case AeadAlgorithmTag.Gcm:
+                return 12;
+            default:
+                throw new ArgumentException("unknown mode: " + aeadAlgorithm);
+            }
+        }
+    }
+}