/// <summary>
/// Decrypts the specified encryptedData and extracts the digital signers if the content was also signed.
/// </summary>
/// <remarks>
/// Decrypts the specified encryptedData and extracts the digital signers if the content was also signed.
/// </remarks>
/// <returns>The decrypted stream.</returns>
/// <param name="encryptedData">The encrypted data.</param>
/// <param name="signatures">A list of digital signatures if the data was both signed and encrypted.</param>
/// <exception cref="System.ArgumentNullException">
/// <paramref name="encryptedData"/> is <c>null</c>.
/// </exception>
/// <exception cref="PrivateKeyNotFoundException">
/// The private key could not be found to decrypt the stream.
/// </exception>
/// <exception cref="System.OperationCanceledException">
/// The user chose to cancel the password prompt.
/// </exception>
/// <exception cref="System.UnauthorizedAccessException">
/// 3 bad attempts were made to unlock the secret key.
/// </exception>
/// <exception cref="Org.BouncyCastle.Bcpg.OpenPgp.PgpException">
/// An OpenPGP error occurred.
/// </exception>
public Stream GetDecryptedStream (Stream encryptedData, out DigitalSignatureCollection signatures)
{
if (encryptedData == null)
throw new ArgumentNullException ("encryptedData");
using (var armored = new ArmoredInputStream (encryptedData)) {
var factory = new PgpObjectFactory (armored);
var obj = factory.NextPgpObject ();
var list = obj as PgpEncryptedDataList;
if (list == null) {
// probably a PgpMarker...
obj = factory.NextPgpObject ();
list = obj as PgpEncryptedDataList;
if (list == null)
throw new PgpException ("Unexpected OpenPGP packet.");
}
PgpPublicKeyEncryptedData encrypted = null;
PrivateKeyNotFoundException pkex = null;
bool hasEncryptedPackets = false;
PgpSecretKey secret = null;
foreach (PgpEncryptedData data in list.GetEncryptedDataObjects ()) {
if ((encrypted = data as PgpPublicKeyEncryptedData) == null)
continue;
hasEncryptedPackets = true;
try {
secret = GetSecretKey (encrypted.KeyId);
break;
} catch (PrivateKeyNotFoundException ex) {
pkex = ex;
}
}
if (!hasEncryptedPackets)
throw new PgpException ("No encrypted packets found.");
if (secret == null)
throw pkex;
factory = new PgpObjectFactory (encrypted.GetDataStream (GetPrivateKey (secret)));
List<IDigitalSignature> onepassList = null;
PgpSignatureList signatureList = null;
PgpCompressedData compressed = null;
var memory = new MemoryBlockStream ();
obj = factory.NextPgpObject ();
while (obj != null) {
if (obj is PgpCompressedData) {
if (compressed != null)
throw new PgpException ("Recursive compression packets are not supported.");
compressed = (PgpCompressedData) obj;
factory = new PgpObjectFactory (compressed.GetDataStream ());
} else if (obj is PgpOnePassSignatureList) {
if (memory.Length == 0) {
var onepasses = (PgpOnePassSignatureList) obj;
onepassList = new List<IDigitalSignature> ();
for (int i = 0; i < onepasses.Count; i++) {
var onepass = onepasses[i];
var pubkey = PublicKeyRingBundle.GetPublicKey (onepass.KeyId);
if (pubkey == null) {
// too messy, pretend we never found a one-pass signature list
onepassList = null;
break;
}
onepass.InitVerify (pubkey);
var signature = new OpenPgpDigitalSignature (pubkey, onepass) {
PublicKeyAlgorithm = GetPublicKeyAlgorithm (onepass.KeyAlgorithm),
DigestAlgorithm = GetDigestAlgorithm (onepass.HashAlgorithm),
};
onepassList.Add (signature);
}
}
} else if (obj is PgpSignatureList) {
signatureList = (PgpSignatureList) obj;
} else if (obj is PgpLiteralData) {
var literal = (PgpLiteralData) obj;
using (var stream = literal.GetDataStream ()) {
var buffer = new byte[4096];
int nread;
while ((nread = stream.Read (buffer, 0, buffer.Length)) > 0) {
if (onepassList != null) {
// update our one-pass signatures...
for (int index = 0; index < nread; index++) {
byte c = buffer[index];
for (int i = 0; i < onepassList.Count; i++) {
var pgp = (OpenPgpDigitalSignature) onepassList[i];
pgp.OnePassSignature.Update (c);
}
}
}
memory.Write (buffer, 0, nread);
}
}
}
obj = factory.NextPgpObject ();
}
memory.Position = 0;
if (signatureList != null) {
if (onepassList != null && signatureList.Count == onepassList.Count) {
for (int i = 0; i < onepassList.Count; i++) {
var pgp = (OpenPgpDigitalSignature) onepassList[i];
pgp.CreationDate = signatureList[i].CreationTime;
pgp.Signature = signatureList[i];
}
signatures = new DigitalSignatureCollection (onepassList);
} else {
signatures = GetDigitalSignatures (signatureList, memory);
memory.Position = 0;
}
} else {
signatures = null;
}
return memory;
}
}
DigitalSignatureCollection GetDigitalSignatures (PgpSignatureList signatureList, Stream content)
{
var signatures = new List<IDigitalSignature> ();
var buf = new byte[4096];
int nread;
for (int i = 0; i < signatureList.Count; i++) {
var pubkey = PublicKeyRingBundle.GetPublicKey (signatureList[i].KeyId);
var signature = new OpenPgpDigitalSignature (pubkey, signatureList[i]) {
PublicKeyAlgorithm = GetPublicKeyAlgorithm (signatureList[i].KeyAlgorithm),
DigestAlgorithm = GetDigestAlgorithm (signatureList[i].HashAlgorithm),
CreationDate = signatureList[i].CreationTime,
};
if (pubkey != null)
signatureList[i].InitVerify (pubkey);
signatures.Add (signature);
}
var memory = content as MemoryStream;
if (memory != null) {
// We can optimize things a bit if we've got a memory stream...
var buffer = memory.GetBuffer ();
for (int index = (int) memory.Position; index < (int) memory.Length; index++) {
byte c = buffer[index];
for (int i = 0; i < signatures.Count; i++) {
if (signatures[i].SignerCertificate != null) {
var pgp = (OpenPgpDigitalSignature) signatures[i];
pgp.Signature.Update (c);
}
}
}
} else {
while ((nread = content.Read (buf, 0, buf.Length)) > 0) {
for (int i = 0; i < signatures.Count; i++) {
if (signatures[i].SignerCertificate != null) {
var pgp = (OpenPgpDigitalSignature) signatures[i];
pgp.Signature.Update (buf, 0, nread);
}
}
}
}
return new DigitalSignatureCollection (signatures);
}
DigitalSignatureCollection GetDigitalSignatures (PgpSignatureList signatureList, Stream content)
{
var signatures = new List<IDigitalSignature> ();
var buf = new byte[4096];
int nread;
for (int i = 0; i < signatureList.Count; i++) {
var pubkey = PublicKeyRingBundle.GetPublicKey (signatureList[i].KeyId);
var signature = new OpenPgpDigitalSignature (pubkey, signatureList[i]) {
PublicKeyAlgorithm = GetPublicKeyAlgorithm (signatureList[i].KeyAlgorithm),
DigestAlgorithm = GetDigestAlgorithm (signatureList[i].HashAlgorithm),
CreationDate = signatureList[i].CreationTime,
};
if (pubkey != null)
signatureList[i].InitVerify (pubkey);
signatures.Add (signature);
}
while ((nread = content.Read (buf, 0, buf.Length)) > 0) {
for (int i = 0; i < signatures.Count; i++) {
if (signatures[i].SignerCertificate != null) {
var pgp = (OpenPgpDigitalSignature) signatures[i];
pgp.Signature.Update (buf, 0, nread);
}
}
}
return new DigitalSignatureCollection (signatures);
}
