diff --git a/Crypto/src/cms/CMSCompressedDataStreamGenerator.cs b/Crypto/src/cms/CMSCompressedDataStreamGenerator.cs
new file mode 100644
index 000000000..13006d4b0
--- /dev/null
+++ b/Crypto/src/cms/CMSCompressedDataStreamGenerator.cs
@@ -0,0 +1,144 @@
+using System;
+using System.IO;
+
+using Org.BouncyCastle.Asn1;
+using Org.BouncyCastle.Asn1.Cms;
+using Org.BouncyCastle.Asn1.X509;
+using Org.BouncyCastle.Utilities.IO;
+using Org.BouncyCastle.Utilities.Zlib;
+
+namespace Org.BouncyCastle.Cms
+{
+ /**
+ * General class for generating a compressed CMS message stream.
+ * <p>
+ * A simple example of usage.
+ * </p>
+ * <pre>
+ * CMSCompressedDataStreamGenerator gen = new CMSCompressedDataStreamGenerator();
+ *
+ * Stream cOut = gen.Open(outputStream, CMSCompressedDataStreamGenerator.ZLIB);
+ *
+ * cOut.Write(data);
+ *
+ * cOut.Close();
+ * </pre>
+ */
+ public class CmsCompressedDataStreamGenerator
+ {
+ public const string ZLib = "1.2.840.113549.1.9.16.3.8";
+
+ private int _bufferSize;
+
+ /**
+ * base constructor
+ */
+ public CmsCompressedDataStreamGenerator()
+ {
+ }
+
+ /**
+ * Set the underlying string size for encapsulated data
+ *
+ * @param bufferSize length of octet strings to buffer the data.
+ */
+ public void SetBufferSize(
+ int bufferSize)
+ {
+ _bufferSize = bufferSize;
+ }
+
+ public Stream Open(
+ Stream outStream,
+ string compressionOID)
+ {
+ return Open(outStream, CmsObjectIdentifiers.Data.Id, compressionOID);
+ }
+
+ public Stream Open(
+ Stream outStream,
+ string contentOID,
+ string compressionOID)
+ {
+ BerSequenceGenerator sGen = new BerSequenceGenerator(outStream);
+
+ sGen.AddObject(CmsObjectIdentifiers.CompressedData);
+
+ //
+ // Compressed Data
+ //
+ BerSequenceGenerator cGen = new BerSequenceGenerator(
+ sGen.GetRawOutputStream(), 0, true);
+
+ // CMSVersion
+ cGen.AddObject(new DerInteger(0));
+
+ // CompressionAlgorithmIdentifier
+ cGen.AddObject(new AlgorithmIdentifier(new DerObjectIdentifier(ZLib)));
+
+ //
+ // Encapsulated ContentInfo
+ //
+ BerSequenceGenerator eiGen = new BerSequenceGenerator(cGen.GetRawOutputStream());
+
+ eiGen.AddObject(new DerObjectIdentifier(contentOID));
+
+ Stream octetStream = CmsUtilities.CreateBerOctetOutputStream(
+ eiGen.GetRawOutputStream(), 0, true, _bufferSize);
+
+ return new CmsCompressedOutputStream(
+ new ZOutputStream(octetStream, JZlib.Z_DEFAULT_COMPRESSION), sGen, cGen, eiGen);
+ }
+
+ private class CmsCompressedOutputStream
+ : BaseOutputStream
+ {
+ private ZOutputStream _out;
+ private BerSequenceGenerator _sGen;
+ private BerSequenceGenerator _cGen;
+ private BerSequenceGenerator _eiGen;
+
+ internal CmsCompressedOutputStream(
+ ZOutputStream outStream,
+ BerSequenceGenerator sGen,
+ BerSequenceGenerator cGen,
+ BerSequenceGenerator eiGen)
+ {
+ _out = outStream;
+ _sGen = sGen;
+ _cGen = cGen;
+ _eiGen = eiGen;
+ }
+
+ public override void WriteByte(
+ byte b)
+ {
+ _out.WriteByte(b);
+ }
+
+ public override void Write(
+ byte[] bytes,
+ int off,
+ int len)
+ {
+ _out.Write(bytes, off, len);
+ }
+
+ protected override void Dispose(bool disposing)
+ {
+ if (disposing)
+ {
+ _out.Dispose();
+
+ // TODO Parent context(s) should really be be closed explicitly
+
+ _eiGen.Close();
+ _cGen.Close();
+ _sGen.Close();
+ }
+
+ base.Dispose(disposing);
+ }
+ }
+ }
+}
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