/// <summary>
/// Finds a secret key out of the given secret keyring that is able
/// to decrypt the current encrypted message and returns its KeyID.
/// If such a key is not found, 0 is returned.
/// </summary>
/// <param name="skrRing">Secret keyring containing all secret keys
/// known to the system.</param>
/// <returns>Returns the KeyID of the key that is able to decrypt the
/// encrypted message.</returns>
/// <remarks>No remarks</remarks>
public ulong GetFittingKeyID(SecretKeyRing skrRing)
{
bool bFound = false;
IEnumerator ieSessionkeys = esKeys.AsymKeys.GetEnumerator();
while (ieSessionkeys.MoveNext())
{
if (!(ieSessionkeys.Current is AsymSessionKeyPacket))
{
throw new Exception("Strange Error!");
}
AsymSessionKeyPacket askpKey = (AsymSessionKeyPacket)ieSessionkeys.Current;
ulong lKeyID = askpKey.KeyID;
TransportableSecretKey tskKey = skrRing.Find(lKeyID);
if (tskKey != null)
{
return(lKeyID);
}
}
if (!bFound)
{
throw new Exception("No fitting secret key was found to decrypt the message!");
}
return(0);
}
/// <summary>
/// Returns true if the given object is the "this" key.
/// </summary>
/// <remarks>
/// The keys are compared by there fingerprint. If the fingerprint
/// is the same, the keys are said to be the same.
/// </remarks>
/// <param name="o">An object that shall be compared against
/// this.</param>
/// <returns>True if the giben object o is the same as the
/// "this" key.</returns>
public override bool Equals(object o)
{
if (o is TransportableSecretKey)
{
TransportableSecretKey tskKey = (TransportableSecretKey)o;
return(tskKey.PrimaryKey.PublicKey.Fingerprint == this.PrimaryKey.PublicKey.Fingerprint);
}
return(false);
}
public static TransportableSecretKey[] SplitKeys(string strRadix64)
{
ArrayList alKeys = new ArrayList();
Packet[] pPackets = Packet.ParsePackets(strRadix64);
byte[] bOneKey = new byte[0];
for (int i = 0; i < pPackets.Length; i++)
{
if (pPackets[i] is SecretKeyPacket)
{
SecretKeyPacket skpKey = (SecretKeyPacket)pPackets[i];
if ((skpKey.Content == ContentTypes.SecretKey) && (bOneKey.Length > 10))
{
TransportableSecretKey tskKey = new TransportableSecretKey(Radix64.Encode(bOneKey, true));
alKeys.Add(tskKey);
bOneKey = new byte[0];
}
}
byte[] bPacket = pPackets[i].Generate();
byte[] bTmpKey = new byte[bOneKey.Length];
bOneKey.CopyTo(bTmpKey, 0);
bOneKey = new byte[bOneKey.Length + bPacket.Length];
Array.Copy(bTmpKey, 0, bOneKey, 0, bTmpKey.Length);
Array.Copy(bPacket, 0, bOneKey, bTmpKey.Length, bPacket.Length);
}
if (bOneKey.Length > 10)
{
TransportableSecretKey tskKey = new TransportableSecretKey(Radix64.Encode(bOneKey, true));
alKeys.Add(tskKey);
}
TransportableSecretKey[] tskKeys = new TransportableSecretKey[alKeys.Count];
int iCount = 0;
IEnumerator ieKeys = alKeys.GetEnumerator();
while (ieKeys.MoveNext())
{
if (!(ieKeys.Current is TransportableSecretKey))
{
continue;
}
tskKeys[iCount++] = (TransportableSecretKey)ieKeys.Current;
}
return(tskKeys);
}
/// <summary>
/// Decrypts the current encrypted message using the secret keys
/// in skrKeyRing and the given passphrase.
/// </summary>
/// <param name="skrKeyRing">The secret keyring containing all the
/// secret keys know to the sytem.</param>
/// <param name="strPassphrase">The passphrase that was used to
/// encrypt the secret key material in the key that decrypts
/// the message.</param>
/// <returns>Returns the message that was encrypted. Usually this is
/// an compressed or literal message.</returns>
/// <remarks>No remarks</remarks>
public Message Decrypt(SecretKeyRing skrKeyRing, string strPassphrase)
{
TransportableSecretKey tskSecretKey = new TransportableSecretKey();
AsymSessionKeyPacket askpSessionKey = new AsymSessionKeyPacket();
bool bFound = false;
// let's see, if we can find a fitting Sessionkey packet
IEnumerator ieSessionkeys = esKeys.AsymKeys.GetEnumerator();
while (ieSessionkeys.MoveNext())
{
if (!(ieSessionkeys.Current is AsymSessionKeyPacket))
{
throw new Exception("Strange Error!");
}
AsymSessionKeyPacket askpKey = (AsymSessionKeyPacket)ieSessionkeys.Current;
ulong lKeyID = askpKey.KeyID;
TransportableSecretKey tskKey = skrKeyRing.Find(lKeyID);
if (tskKey != null)
{
bFound = true;
tskSecretKey = tskKey;
askpSessionKey = askpKey;
}
}
if (!bFound)
{
throw new Exception("No fitting secret key was found to decrypt the message!");
}
askpSessionKey.DecryptSessionKey(tskSecretKey, strPassphrase);
byte[] bKey = askpSessionKey.SessionKey;
Packet[] pContent = new Packet[0];
try {
SymmetricAlgorithm saAlgo = CipherHelper.CreateSymAlgorithm(askpSessionKey.SymmetricAlgorithm);
pContent = sepData.Decrypt(bKey, saAlgo);
} catch (Exception e) {
throw new System.Exception("Decryption of the Message failed: " + e.Message);
}
// now we need to look what kind of message was hidden in the
// encrypted data
// it can be either a literal message
LiteralMessage lmLiteral = new LiteralMessage();
try {
int iPos = lmLiteral.ParseMessage(pContent);
return(lmLiteral);
} catch (Exception) {}
// or an compressed Message
CompressedMessage cmCompressed = new CompressedMessage();
try {
int iPos = cmCompressed.ParseMessage(pContent);
return(cmCompressed);
} catch (Exception) {}
throw new System.ArgumentException("Encrypted package content is not a valid message!");
}