/* PokerTH automated tests.
Copyright (C) 2010 Lothar May
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU Affero General Public License as
published by the Free Software Foundation, either version 3 of the
License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Affero General Public License for more details.
You should have received a copy of the GNU Affero General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package de.pokerth.test;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.util.StringTokenizer;
import de.rtner.security.auth.spi.MacBasedPRF;
import de.rtner.security.auth.spi.PBKDF2Engine;
import de.rtner.security.auth.spi.PBKDF2Parameters;
public class ScramSha1 {
String clientFirstMessageBare;
SecureRandom random = new SecureRandom();
public String executeStep1(String username)
{
byte bytes[] = new byte[8];
random.nextBytes(bytes);
String clientR = Base64Coder.encodeLines(bytes).trim();
clientFirstMessageBare = "n=" + username + ",r=" + clientR + "\n";
return "n,," + clientFirstMessageBare;
}
public String executeStep2(String password, String serverFirstMessage) throws NoSuchAlgorithmException
{
MessageDigest md = MessageDigest.getInstance("SHA-1");
MacBasedPRF hmac = new MacBasedPRF("HMacSha1");
StringTokenizer st = new StringTokenizer(serverFirstMessage, "=", true);
st.nextToken("=");
st.nextToken();
String serverR = st.nextToken(",");
st.nextToken();
st.nextToken("=");
st.nextToken();
byte[] serverSalt = Base64Coder.decodeLines(st.nextToken(","));
st.nextToken();
st.nextToken("=");
st.nextToken();
String iterationCount = st.nextToken(",");
// SaltedPassword := Hi(Normalize(password), salt, i)
PBKDF2Engine engine = new PBKDF2Engine(new PBKDF2Parameters("HMacSHA1", null, serverSalt, Integer.parseInt(iterationCount)));
byte[] saltedPassword = engine.deriveKey(password, 20);
// ClientKey := HMAC(SaltedPassword, "Client Key")
hmac.init(saltedPassword);
byte[] clientKey = hmac.doFinal("Client Key".getBytes());
// StoredKey := H(ClientKey)
byte[] storedKey = md.digest(clientKey);
// AuthMessage := client-first-message-bare + "," +
// server-first-message + "," +
// client-final-message-without-proof
String clientFinalMessage = "c=biws,r=" + serverR;
String strAuthMessage = clientFirstMessageBare + "," + serverFirstMessage + "," + clientFinalMessage;
// ClientSignature := HMAC(StoredKey, AuthMessage)
hmac = new MacBasedPRF("HMacSha1");
hmac.init(storedKey);
byte[] clientSignature = hmac.doFinal(strAuthMessage.getBytes());
// ClientProof := ClientKey XOR ClientSignature
for (int i = 0; i < 20; i++)
{
clientKey[i] ^= clientSignature[i];
}
String clientProof = Base64Coder.encodeLines(clientKey).trim();
clientFinalMessage += ",p=" + clientProof;
return clientFinalMessage;
}
}