public void CloseSecureChannel()
{
if (SessionKeys != null)
{
SessionKeys = null;
}
}
public static byte[] EncryptAPDUData(DaplugSessionKeys keyset, APDUCommand apdu)
{
byte[] paddedData = AddPadding(apdu.CommandData);
byte[] encryptedData = Crypto.TripleDESEncrypt(keyset.SEncKey, paddedData);
return(encryptedData);
}
public static byte[] CalculateCryptogram(DaplugSessionKeys keyset, byte[] hostChallenge, byte[] cardChallenge)
{
byte[] challengesAndPadding = hostChallenge.Concat(cardChallenge).Concat(padding).ToArray();
byte[] buffer = Crypto.TripleDESEncrypt(keyset.SEncKey, challengesAndPadding);
byte[] cryptogram = new byte[8];
System.Array.Copy(buffer, 16, cryptogram, 0, 8);
return(cryptogram);
}
public static DaplugSessionKeys ComputeSessionKeys(DaplugKeySet keyset, byte[] seqCounter)
{
byte[] dataToEncrypt = new byte[16];
Array.Copy(seqCounter, 0, dataToEncrypt, 2, 2);
byte[] SEncBytes = new byte[2] {
0x01, 0x82
};
byte[] REncBytes = new byte[2] {
0x01, 0x83
};
byte[] CMacEncBytes = new byte[2] {
0x01, 0x01
};
byte[] RMacEncBytes = new byte[2] {
0x01, 0x02
};
byte[] SKekEncBytes = new byte[2] {
0x01, 0x81
};
DaplugSessionKeys sessionKeys = new DaplugSessionKeys();
Array.Copy(SEncBytes, 0, dataToEncrypt, 0, 2);
sessionKeys.SEncKey = Crypto.TripleDESEncrypt(keyset.EncKey, dataToEncrypt);
Array.Copy(REncBytes, 0, dataToEncrypt, 0, 2);
sessionKeys.REncKey = Crypto.TripleDESEncrypt(keyset.EncKey, dataToEncrypt);
Array.Copy(CMacEncBytes, 0, dataToEncrypt, 0, 2);
sessionKeys.CMacKey = Crypto.TripleDESEncrypt(keyset.MacKey, dataToEncrypt);
Array.Copy(RMacEncBytes, 0, dataToEncrypt, 0, 2);
sessionKeys.RMacKey = Crypto.TripleDESEncrypt(keyset.MacKey, dataToEncrypt);
Array.Copy(SKekEncBytes, 0, dataToEncrypt, 0, 2);
sessionKeys.SKEKey = Crypto.TripleDESEncrypt(keyset.DeKey, dataToEncrypt);
return(sessionKeys);
}
internal static byte[] DecryptAPDUResponse(DaplugSessionKeys keyset, byte[] responseBytes)
{
byte[] decryptedResponse = Crypto.TripleDESDecrypt(keyset.REncKey, responseBytes);
return(RemovePadding(decryptedResponse));
}
public async Task OpenSecureChannelAsync(DaplugKeySet keyset, DaplugSecurityLevel securityLevel, byte[] diversifier = null, byte[] hostChallenge = null)
{
if (keyset.EncKey == null || keyset.MacKey == null || keyset.DeKey == null)
{
throw new DaplugAPIException("Invalid keyset.");
}
if (hostChallenge == null)
{
Random rnd = new Random();
hostChallenge = new byte[8];
rnd.NextBytes(hostChallenge);
}
var authCommandHeader = new byte[] { 0x80, 0x50, keyset.Version, 0x00, 0x00 };
var authCommand = new APDUCommand(authCommandHeader, hostChallenge);
var response = await ExchangeAPDUAsync(authCommand);
if (response.IsSuccessfulResponse == false)
{
throw new DaplugAPIException("INITIALIZE UPDATE failed.", response.SW1, response.SW2);
}
byte[] counter = new byte[2];
byte[] cardChallenge = new byte[8];
byte[] cardCryptogram = new byte[8];
Array.Copy(response.ResponseData, 12, counter, 0, 2);
Array.Copy(response.ResponseData, 12, cardChallenge, 0, 8);
Array.Copy(response.ResponseData, 20, cardCryptogram, 0, 8);
var tempSessionKeys = DaplugCrypto.ComputeSessionKeys(keyset, counter);
var computedCardCryptogram = DaplugCrypto.CalculateCryptogram(tempSessionKeys, hostChallenge, cardChallenge);
if (computedCardCryptogram.SequenceEqual(cardCryptogram) == false)
{
throw new DaplugAPIException("Invalid card cryptogram.");
}
var hostCryptogram = DaplugCrypto.CalculateCryptogram(tempSessionKeys, cardChallenge, hostChallenge);
if (securityLevel.HasFlag(DaplugSecurityLevel.COMMAND_MAC) == false)
{
securityLevel |= DaplugSecurityLevel.COMMAND_MAC;
}
tempSessionKeys.SecurityLevel = securityLevel;
SessionKeys = tempSessionKeys;
var extAuthCommandHeader = new byte[] { 0x80, 0x82, (byte)SessionKeys.SecurityLevel, 0x00, 0x00 };
var extAuthCommand = new APDUCommand(extAuthCommandHeader, hostCryptogram);
var extAuthResponse = await ExchangeAPDUAsync(extAuthCommand);
if (extAuthResponse.IsSuccessfulResponse == false)
{
SessionKeys = null;
throw new DaplugAPIException("EXTERNAL AUTHENTICATE failed.", response.SW1, response.SW2);
}
Array.Copy(SessionKeys.CMac, SessionKeys.RMac, 8);
}
