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Copy pathNTSKEHandshake.java
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139 lines (113 loc) · 5.26 KB
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package nts;
import java.io.IOException;
import java.security.Security;
import javax.net.ssl.*;
import nts.NTSKERecords.Constants.AEADAlgorithms;
import nts.NTSKERecords.Constants.NTSNextProtocols;
import nts.NTSKERecords.NTSKERecordFactory;
import org.conscrypt.Conscrypt;
public class NTSKEHandshake {
public static String LABEL = "EXPORTER-network-time-security";
public static byte[] PROTO_ID_NTPV4 = {0x00, 0x00};
public static byte[] AEAD_AES_SIV_CMAC_256 = {0x00, (byte) 0x0F};
public static byte C2S_CONTEXT = 0x00;
public static byte S2C_CONTEXT = 0x01;
private SSLSocketFactory factory;
public NTSKEHandshake() {
// Create a TLSv1.3 socket using Conscrypt to have access to exportKeyingMaterial
try {
Security.insertProviderAt(Conscrypt.newProvider(), 1);
X509TrustManager tm = Conscrypt.getDefaultX509TrustManager();
SSLContext context = SSLContext.getInstance("TLSv1.3", "Conscrypt");
context.init(null, new TrustManager[] {tm}, null);
factory = context.getSocketFactory();
} catch (Exception e) {
e.printStackTrace();
}
}
private static void printSession(SSLSession session) {
try {
System.out.println("Protocol: " + session.getProtocol());
System.out.println("Cipher Suite: " + session.getCipherSuite());
System.out.println("Peer Host: " + session.getPeerHost());
System.out.println("Peer Port: " + session.getPeerPort());
// System.out.println(session.getPeerCertificates()[0]);
} catch (Exception e) {
e.printStackTrace();
}
}
private static byte[] getKeyExpansionContext(byte CS2orS2C) {
byte[] key_extraction_context = new byte[5];
System.arraycopy(PROTO_ID_NTPV4, 0, key_extraction_context, 0, 2);
System.arraycopy(AEAD_AES_SIV_CMAC_256, 0, key_extraction_context, 2, 2);
key_extraction_context[4] = CS2orS2C;
return key_extraction_context;
}
public NTSConfig doHandshake(String host, int port) {
try {
SSLSocket socket = (SSLSocket) factory.createSocket(host, port);
// Must be TLSv1.3 and ALPN Offer "ntske/1"
SSLParameters params = socket.getSSLParameters();
params.setProtocols(new String[] {"TLSv1.3"});
// params.setApplicationProtocols(new String[] { "ntske/1" });
socket.setSSLParameters(params);
socket.setSoTimeout(300);
// Weird issue on android:
// Conscrypt does not seems to use the application protocol from the ssl Params
// (https://github.com/google/conscrypt/issues/832)
// Need to be sneaky
Conscrypt.setApplicationProtocols(socket, new String[] {"ntske/1"});
socket.startHandshake();
// printSession(socket.getSession());
// System.out.println("Conscrypt v" + Conscrypt.version().major() + "." +
// Conscrypt.version().minor() + "." + Conscrypt.version().patch());
// System.out.println("Cipher Suites: " + String.join(", ", socket.getEnabledCipherSuites()));
// System.out.println("Protocols : " + String.join(", ", socket.getEnabledProtocols()));
// System.out.println("App Protocols: " + socket.getApplicationProtocol());
// Create NTSKE Client Message
NTSKEMessage NtsKeClientMessage = new NTSKEMessage();
NtsKeClientMessage.addNTSKERecord(
NTSKERecordFactory.getNTSNextProtocolNegotiationRecord(NTSNextProtocols.NTPv4));
NtsKeClientMessage.addNTSKERecord(
NTSKERecordFactory.getAEADAlgorithmNegotiationRecord(
AEADAlgorithms.AEAD_AES_SIV_CMAC_256));
NtsKeClientMessage.addNTSKERecord(NTSKERecordFactory.getEndOfMessageRecord());
// System.out.println("\nNTSKE Client Message:");
// System.out.println(NtsKeClientMessage);
// System.out.println(NtsKeClientMessage.toByteString());
socket.getOutputStream().write(NtsKeClientMessage.toBytes());
socket.getOutputStream().flush();
// Read Response
byte[] response = new byte[1024];
int bytesRead = socket.getInputStream().read(response);
if (bytesRead < 0) {
throw new IOException("Unable to read NTS KE Response from server");
}
// Create NTSKE Response Message
NTSKEMessage NTSKEResponseMessage = NTSKEMessage.parseNTSKERawMessage(response, bytesRead);
// System.out.println("\nNTSKE Server Message: " + bytesRead + " bytes");
// System.out.println(NTSKEResponseMessage);
// System.out.println(NTSKEResponseMessage.toByteString());
// Derive client and server keys from TLS handshake
byte[] context_c2s = getKeyExpansionContext(C2S_CONTEXT);
byte[] context_s2c = getKeyExpansionContext(S2C_CONTEXT);
byte[] c2s_key = Conscrypt.exportKeyingMaterial(socket, LABEL, context_c2s, 32);
byte[] s2c_key = Conscrypt.exportKeyingMaterial(socket, LABEL, context_s2c, 32);
socket.close();
NTSConfig ntsConfig = NTSKEResponseMessage.parseResponse(host, port);
ntsConfig.C2SKey = c2s_key;
ntsConfig.S2CKey = s2c_key;
return ntsConfig;
} catch (Exception e) {
e.printStackTrace();
return null;
}
}
public static void main(String[] args) {
String host = "ntppool1.time.nl";
int port = 4460;
NTSKEHandshake tlsHandshake = new NTSKEHandshake();
NTSConfig ntsConfig = tlsHandshake.doHandshake(host, port);
System.out.println("Result: " + ntsConfig);
}
}