public static Stream PgpDecrypt(
Stream encryptedData,
string armoredPrivateKey,
string privateKeyPassword,
Encoding armorEncoding = null)
{
armorEncoding = armorEncoding ?? Encoding.UTF8;
var stream = PgpUtilities.GetDecoderStream(encryptedData);
var layeredStreams = new List <Stream> {
stream
}; //this is to clean up/ dispose of any layered streams.
var dataObjectFactory = new PgpObjectFactory(stream);
var dataObject = dataObjectFactory.NextPgpObject();
Dictionary <long, PgpSecretKey> secretKeys;
using (var privateKeyStream = armoredPrivateKey.Streamify(armorEncoding))
{
var secRings = new PgpSecretKeyRingBundle(PgpUtilities.GetDecoderStream(privateKeyStream)).GetKeyRings()
.OfType <PgpSecretKeyRing>();
var pgpSecretKeyRings = secRings as PgpSecretKeyRing[] ?? secRings.ToArray();
if (!pgpSecretKeyRings.Any())
{
throw new ArgumentException("No secret keys found.");
}
secretKeys = pgpSecretKeyRings.SelectMany(x => x.GetSecretKeys().OfType <PgpSecretKey>())
.ToDictionary(key => key.KeyId, value => value);
}
while (!(dataObject is PgpLiteralData) && dataObject != null)
{
try
{
PgpCompressedData compressedData = null;
PgpEncryptedDataList listedData = null;
if (dataObject as PgpCompressedData != null)
{
compressedData = dataObject as PgpCompressedData;
}
if (dataObject as PgpEncryptedDataList != null)
{
listedData = dataObject as PgpEncryptedDataList;
}
if (compressedData == null && listedData == null)
{
return(null);
}
//strip away the compression stream
if (compressedData != null)
{
stream = compressedData.GetDataStream();
layeredStreams.Add(stream);
dataObjectFactory = new PgpObjectFactory(stream);
}
//strip the PgpEncryptedDataList
if (listedData != null)
{
var encryptedDataList = listedData.GetEncryptedDataObjects().OfType <PgpPublicKeyEncryptedData>().First();
var decryptionKey = secretKeys[encryptedDataList.KeyId].ExtractPrivateKey(privateKeyPassword.ToCharArray());
stream = encryptedDataList.GetDataStream(decryptionKey);
layeredStreams.Add(stream);
dataObjectFactory = new PgpObjectFactory(stream);
}
dataObject = dataObjectFactory.NextPgpObject();
} catch (Exception ex) {
throw new PgpException("Failed to strip encapsulating streams.", ex);
}
}
foreach (var layeredStream in layeredStreams)
{
layeredStream.Close();
layeredStream.Dispose();
}
if (dataObject == null)
{
return(null);
}
var literalData = (PgpLiteralData)dataObject;
var ms = new MemoryStream();
using (var clearData = literalData.GetInputStream())
{
Streams.PipeAll(clearData, ms);
}
ms.Position = 0;
return(ms);
}
