Hi, I have to run a diffie hellman key exchange code on two different machines. But I need to separate the code into two. Can anyone guide please.
The code is available on
http://docs.oracle.com/javase/7/docs/technotes/guides/security/crypto/CryptoSpec.html#DH2Ex[
^]
I would really appreciate if anyone could help. :)
import java.io.*;
import java.math.BigInteger;
import java.security.*;
import java.security.spec.*;
import java.security.interfaces.*;
import javax.crypto.*;
import javax.crypto.spec.*;
import javax.crypto.interfaces.*;
import com.sun.crypto.provider.SunJCE;
public class DHKeyAgreement2 {
private DHKeyAgreement2() {}
public static void main(String argv[]) {
try {
String mode = "USE_SKIP_DH_PARAMS";
DHKeyAgreement2 keyAgree = new DHKeyAgreement2();
if (argv.length > 1) {
keyAgree.usage();
throw new Exception("Wrong number of command options");
} else if (argv.length == 1) {
if (!(argv[0].equals("-gen"))) {
keyAgree.usage();
throw new Exception("Unrecognized flag: " + argv[0]);
}
mode = "GENERATE_DH_PARAMS";
}
keyAgree.run(mode);
} catch (Exception e) {
System.err.println("Error: " + e);
System.exit(1);
}
}
private void run(String mode) throws Exception {
DHParameterSpec dhSkipParamSpec;
if (mode.equals("GENERATE_DH_PARAMS")) {
System.out.println
("Creating Diffie-Hellman parameters (takes VERY long) ...");
AlgorithmParameterGenerator paramGen
= AlgorithmParameterGenerator.getInstance("DH");
paramGen.init(512);
AlgorithmParameters params = paramGen.generateParameters();
dhSkipParamSpec = (DHParameterSpec)params.getParameterSpec
(DHParameterSpec.class);
} else {
System.out.println("Using SKIP Diffie-Hellman parameters");
dhSkipParamSpec = new DHParameterSpec(skip1024Modulus,
skip1024Base);
}
System.out.println("ALICE: Generate DH keypair ...");
KeyPairGenerator aliceKpairGen = KeyPairGenerator.getInstance("DH");
aliceKpairGen.initialize(dhSkipParamSpec);
KeyPair aliceKpair = aliceKpairGen.generateKeyPair();
System.out.println("ALICE: Initialization ...");
KeyAgreement aliceKeyAgree = KeyAgreement.getInstance("DH");
aliceKeyAgree.init(aliceKpair.getPrivate());
byte[] alicePubKeyEnc = aliceKpair.getPublic().getEncoded();
KeyFactory bobKeyFac = KeyFactory.getInstance("DH");
X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec
(alicePubKeyEnc);
PublicKey alicePubKey = bobKeyFac.generatePublic(x509KeySpec);
DHParameterSpec dhParamSpec = ((DHPublicKey)alicePubKey).getParams();
System.out.println("BOB: Generate DH keypair ...");
KeyPairGenerator bobKpairGen = KeyPairGenerator.getInstance("DH");
bobKpairGen.initialize(dhParamSpec);
KeyPair bobKpair = bobKpairGen.generateKeyPair();
System.out.println("BOB: Initialization ...");
KeyAgreement bobKeyAgree = KeyAgreement.getInstance("DH");
bobKeyAgree.init(bobKpair.getPrivate());
byte[] bobPubKeyEnc = bobKpair.getPublic().getEncoded();
KeyFactory aliceKeyFac = KeyFactory.getInstance("DH");
x509KeySpec = new X509EncodedKeySpec(bobPubKeyEnc);
PublicKey bobPubKey = aliceKeyFac.generatePublic(x509KeySpec);
System.out.println("ALICE: Execute PHASE1 ...");
aliceKeyAgree.doPhase(bobPubKey, true);
System.out.println("BOB: Execute PHASE1 ...");
bobKeyAgree.doPhase(alicePubKey, true);
byte[] aliceSharedSecret = aliceKeyAgree.generateSecret();
int aliceLen = aliceSharedSecret.length;
byte[] bobSharedSecret = new byte[aliceLen];
int bobLen;
try {
bobLen = bobKeyAgree.generateSecret(bobSharedSecret, 1);
} catch (ShortBufferException e) {
System.out.println(e.getMessage());
}
bobLen = bobKeyAgree.generateSecret(bobSharedSecret, 0);
System.out.println("Alice secret: " +
toHexString(aliceSharedSecret));
System.out.println("Bob secret: " +
toHexString(bobSharedSecret));
if (!java.util.Arrays.equals(aliceSharedSecret, bobSharedSecret))
throw new Exception("Shared secrets differ");
System.out.println("Shared secrets are the same");
System.out.println("Return shared secret as SecretKey object ...");
bobKeyAgree.doPhase(alicePubKey, true);
SecretKey bobDesKey = bobKeyAgree.generateSecret("DES");
aliceKeyAgree.doPhase(bobPubKey, true);
SecretKey aliceDesKey = aliceKeyAgree.generateSecret("DES");
Cipher bobCipher = Cipher.getInstance("DES/ECB/PKCS5Padding");
bobCipher.init(Cipher.ENCRYPT_MODE, bobDesKey);
byte[] cleartext = "This is just an example".getBytes();
byte[] ciphertext = bobCipher.doFinal(cleartext);
Cipher aliceCipher = Cipher.getInstance("DES/ECB/PKCS5Padding");
aliceCipher.init(Cipher.DECRYPT_MODE, aliceDesKey);
byte[] recovered = aliceCipher.doFinal(ciphertext);
if (!java.util.Arrays.equals(cleartext, recovered))
throw new Exception("DES in CBC mode recovered text is " +
"different from cleartext");
System.out.println("DES in ECB mode recovered text is " +
"same as cleartext");
bobCipher = Cipher.getInstance("DES/CBC/PKCS5Padding");
bobCipher.init(Cipher.ENCRYPT_MODE, bobDesKey);
cleartext = "This is just an example".getBytes();
ciphertext = bobCipher.doFinal(cleartext);
byte[] encodedParams = bobCipher.getParameters().getEncoded();
AlgorithmParameters params = AlgorithmParameters.getInstance("DES");
params.init(encodedParams);
aliceCipher = Cipher.getInstance("DES/CBC/PKCS5Padding");
aliceCipher.init(Cipher.DECRYPT_MODE, aliceDesKey, params);
recovered = aliceCipher.doFinal(ciphertext);
if (!java.util.Arrays.equals(cleartext, recovered))
throw new Exception("DES in CBC mode recovered text is " +
"different from cleartext");
System.out.println("DES in CBC mode recovered text is " +
"same as cleartext");
}
private void byte2hex(byte b, StringBuffer buf) {
char[] hexChars = { '0', '1', '2', '3', '4', '5', '6', '7', '8',
'9', 'A', 'B', 'C', 'D', 'E', 'F' };
int high = ((b & 0xf0) >> 4);
int low = (b & 0x0f);
buf.append(hexChars[high]);
buf.append(hexChars[low]);
}
private String toHexString(byte[] block) {
StringBuffer buf = new StringBuffer();
int len = block.length;
for (int i = 0; i < len; i++) {
byte2hex(block[i], buf);
if (i < len-1) {
buf.append(":");
}
}
return buf.toString();
}
private void usage() {
System.err.print("DHKeyAgreement usage: ");
System.err.println("[-gen]");
}
private static final byte skip1024ModulusBytes[] = {
(byte)0xF4, (byte)0x88, (byte)0xFD, (byte)0x58,
(byte)0x4E, (byte)0x49, (byte)0xDB, (byte)0xCD,
(byte)0x20, (byte)0xB4, (byte)0x9D, (byte)0xE4,
(byte)0x91, (byte)0x07, (byte)0x36, (byte)0x6B,
(byte)0x33, (byte)0x6C, (byte)0x38, (byte)0x0D,
(byte)0x45, (byte)0x1D, (byte)0x0F, (byte)0x7C,
(byte)0x88, (byte)0xB3, (byte)0x1C, (byte)0x7C,
(byte)0x5B, (byte)0x2D, (byte)0x8E, (byte)0xF6,
(byte)0xF3, (byte)0xC9, (byte)0x23, (byte)0xC0,
(byte)0x43, (byte)0xF0, (byte)0xA5, (byte)0x5B,
(byte)0x18, (byte)0x8D, (byte)0x8E, (byte)0xBB,
(byte)0x55, (byte)0x8C, (byte)0xB8, (byte)0x5D,
(byte)0x38, (byte)0xD3, (byte)0x34, (byte)0xFD,
(byte)0x7C, (byte)0x17, (byte)0x57, (byte)0x43,
(byte)0xA3, (byte)0x1D, (byte)0x18, (byte)0x6C,
(byte)0xDE, (byte)0x33, (byte)0x21, (byte)0x2C,
(byte)0xB5, (byte)0x2A, (byte)0xFF, (byte)0x3C,
(byte)0xE1, (byte)0xB1, (byte)0x29, (byte)0x40,
(byte)0x18, (byte)0x11, (byte)0x8D, (byte)0x7C,
(byte)0x84, (byte)0xA7, (byte)0x0A, (byte)0x72,
(byte)0xD6, (byte)0x86, (byte)0xC4, (byte)0x03,
(byte)0x19, (byte)0xC8, (byte)0x07, (byte)0x29,
(byte)0x7A, (byte)0xCA, (byte)0x95, (byte)0x0C,
(byte)0xD9, (byte)0x96, (byte)0x9F, (byte)0xAB,
(byte)0xD0, (byte)0x0A, (byte)0x50, (byte)0x9B,
(byte)0x02, (byte)0x46, (byte)0xD3, (byte)0x08,
(byte)0x3D, (byte)0x66, (byte)0xA4, (byte)0x5D,
(byte)0x41, (byte)0x9F, (byte)0x9C, (byte)0x7C,
(byte)0xBD, (byte)0x89, (byte)0x4B, (byte)0x22,
(byte)0x19, (byte)0x26, (byte)0xBA, (byte)0xAB,
(byte)0xA2, (byte)0x5E, (byte)0xC3, (byte)0x55,
(byte)0xE9, (byte)0x2F, (byte)0x78, (byte)0xC7
};
private static final BigInteger skip1024Modulus
= new BigInteger(1, skip1024ModulusBytes);
private static final BigInteger skip1024Base = BigInteger.valueOf(2);
}