public void EncryptPackets(SymmetricAlgorithm keyedAlgorithm, params OpenPgpPacket[] packetsToEncrypt)
{
var transform = new OpenPgpCfbTransform(keyedAlgorithm, encrypt: true);
var msEncrypted = new MemoryStream();
EncryptedStream = msEncrypted;
var encryptor = new CryptoStream(msEncrypted, transform, CryptoStreamMode.Write);
// HACK: Write the prefix bytes manually rather than do it all in the transform since we need it for the hash
encryptor.Write(transform.PrefixBytes, 0, transform.PrefixBytes.Length);
var hasher = SHA1.Create();
var hashContentsStream = new MemoryStream();
var hashStream = new CryptoStream(hashContentsStream, hasher, CryptoStreamMode.Write);
hashStream.Write(transform.PrefixBytes, 0, transform.PrefixBytes.Length);
var currentPacketStream = new MemoryStream();
foreach (var currentPacketToEncrypt in packetsToEncrypt)
{
currentPacketStream.SetLength(0);
currentPacketToEncrypt.WriteTo(currentPacketStream);
currentPacketStream.Position = 0;
currentPacketStream.CopyTo(hashStream);
currentPacketStream.Position = 0;
currentPacketStream.CopyTo(encryptor);
}
var mdcPacket = new ModificationDetectionCodeOpenPgpPacket();
mdcPacket.Header.Length = hasher.HashSize / 8;
mdcPacket.Header.WriteTo(hashStream);
hashStream.FlushFinalBlock();
var hashContents = hasher.Hash;
mdcPacket.HashValue = hashContents;
mdcPacket.WriteTo(encryptor);
// SECREVIEW: Emit MDC packet
encryptor.FlushFinalBlock();
msEncrypted.Position = 0;
}
// Throw error if not valid
public IEnumerable <OpenPgpPacket> GetDecryptedPackets(SymmetricAlgorithm keyedAlgorithm)
{
var transform = new OpenPgpCfbTransform(keyedAlgorithm, encrypt: false);
var decryptor = new CryptoStream(EncryptedStream, transform, CryptoStreamMode.Read);
var decrypted = new MemoryStream();
decryptor.CopyTo(decrypted);
// Get rid of the modification detection code, but verify it
var mdcStart = decrypted.Length - (1 + 1 + 20);
decrypted.Position = mdcStart;
var mdcStream = new MemoryStream();
decrypted.CopyTo(mdcStream);
decrypted.Position = 0;
decrypted.SetLength(mdcStart + 2);
var hasher = SHA1.Create();
var hashIncludingHeaderAndLength = hasher.ComputeHash(transform.PrefixBytes.Concat(decrypted.ToArray()).ToArray());
decrypted.SetLength(decrypted.Length - 2);
decrypted.Position = 0;
// TODO:
mdcStream.Position = 0;
var mdc = OpenPgpPacketReader.ReadAllPackets(mdcStream).First() as ModificationDetectionCodeOpenPgpPacket;
for (int i = 0; i < hashIncludingHeaderAndLength.Length; i++)
{
if (hashIncludingHeaderAndLength[i] != mdc.HashValue[i])
{
throw new ModificationDetectedException();
}
}
return(OpenPgpPacketReader.ReadAllPackets(decrypted));
}
// Throw error if not valid
public IEnumerable<OpenPgpPacket> GetDecryptedPackets(SymmetricAlgorithm keyedAlgorithm)
{
var transform = new OpenPgpCfbTransform(keyedAlgorithm, encrypt:false);
var decryptor = new CryptoStream(EncryptedStream, transform, CryptoStreamMode.Read);
var decrypted = new MemoryStream();
decryptor.CopyTo(decrypted);
// Get rid of the modification detection code, but verify it
var mdcStart = decrypted.Length - (1 + 1 + 20);
decrypted.Position = mdcStart;
var mdcStream = new MemoryStream();
decrypted.CopyTo(mdcStream);
decrypted.Position = 0;
decrypted.SetLength(mdcStart + 2);
var hasher = SHA1.Create();
var hashIncludingHeaderAndLength = hasher.ComputeHash(transform.PrefixBytes.Concat(decrypted.ToArray()).ToArray());
decrypted.SetLength(decrypted.Length - 2);
decrypted.Position = 0;
// TODO:
mdcStream.Position = 0;
var mdc = OpenPgpPacketReader.ReadAllPackets(mdcStream).First() as ModificationDetectionCodeOpenPgpPacket;
for(int i = 0; i < hashIncludingHeaderAndLength.Length; i++) {
if(hashIncludingHeaderAndLength[i] != mdc.HashValue[i]) {
throw new ModificationDetectedException();
}
}
return OpenPgpPacketReader.ReadAllPackets(decrypted);
}
public void EncryptPackets(SymmetricAlgorithm keyedAlgorithm, params OpenPgpPacket[] packetsToEncrypt)
{
var transform = new OpenPgpCfbTransform(keyedAlgorithm, encrypt: true);
var msEncrypted = new MemoryStream();
EncryptedStream = msEncrypted;
var encryptor = new CryptoStream(msEncrypted, transform, CryptoStreamMode.Write);
// HACK: Write the prefix bytes manually rather than do it all in the transform since we need it for the hash
encryptor.Write(transform.PrefixBytes, 0, transform.PrefixBytes.Length);
var hasher = SHA1.Create();
var hashContentsStream = new MemoryStream();
var hashStream = new CryptoStream(hashContentsStream, hasher, CryptoStreamMode.Write);
hashStream.Write(transform.PrefixBytes, 0, transform.PrefixBytes.Length);
var currentPacketStream = new MemoryStream();
foreach(var currentPacketToEncrypt in packetsToEncrypt) {
currentPacketStream.SetLength(0);
currentPacketToEncrypt.WriteTo(currentPacketStream);
currentPacketStream.Position = 0;
currentPacketStream.CopyTo(hashStream);
currentPacketStream.Position = 0;
currentPacketStream.CopyTo(encryptor);
}
var mdcPacket = new ModificationDetectionCodeOpenPgpPacket();
mdcPacket.Header.Length = hasher.HashSize/8;
mdcPacket.Header.WriteTo(hashStream);
hashStream.FlushFinalBlock();
var hashContents = hasher.Hash;
mdcPacket.HashValue = hashContents;
mdcPacket.WriteTo(encryptor);
// SECREVIEW: Emit MDC packet
encryptor.FlushFinalBlock();
msEncrypted.Position = 0;
}