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import java.math.BigInteger;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import javax.crypto.KeyAgreement;
import javax.crypto.SecretKey;
import javax.crypto.interfaces.DHPrivateKey;
import javax.crypto.interfaces.DHPublicKey;
import javax.crypto.spec.DHParameterSpec;
public class MainClass {
public static void main(String[] args) throws Exception {
String s = "F488FD584E49DBCD20B49DE49107366B336C380D451D0F7C88"
+ "11111111111111111111111111111111111111111111111111"
+ "11111111111111111111111111111111111111111111111111"
+ "11111111111111111111111111111111111111111111111111"
+ "11111111111111111111111111111111111111111111111111" + "2F78C7";
BigInteger base = BigInteger.valueOf(2);
BigInteger modulous = new BigInteger(s, 16);
DHParameterSpec skipParameterSpec = new DHParameterSpec(modulous, base);
KeyPairGenerator kpg1 = KeyPairGenerator.getInstance("DH");
kpg1.initialize(skipParameterSpec);
KeyPair kp1 = kpg1.generateKeyPair();
KeyAgreement ka1 = KeyAgreement.getInstance("DH");
DHPrivateKey privateKey1 = (DHPrivateKey) kp1.getPrivate();
DHPublicKey publicKey1 = (DHPublicKey) kp1.getPublic();
ka1.init(privateKey1);
System.out.println("1 is using " + publicKey1.getY() + " for its public key");
KeyPairGenerator kpg2 = KeyPairGenerator.getInstance("DH");
kpg2.initialize(skipParameterSpec);
KeyPair kp2 = kpg2.generateKeyPair();
KeyAgreement ka2 = KeyAgreement.getInstance("DH");
DHPrivateKey privateKey2 = (DHPrivateKey) kp2.getPrivate();
DHPublicKey publicKey2 = (DHPublicKey) kp2.getPublic();
ka2.init(privateKey2);
System.out.println("2 is using " + publicKey2.getY() + "for its public key");
// Use the KeyAgreement object of 1 to generate its shared key
ka1.doPhase(publicKey2, true);
SecretKey sharedKey1 = ka1.generateSecret("DES");
System.out.println("1 is using " + new String(sharedKey1.getEncoded())
+ " as its DES session key");
// Use the KeyAgreement object of 2 to generate its shared key
ka2.doPhase(publicKey1, true);
SecretKey sharedKey2 = ka2.generateSecret("DES");
System.out.println("2 is using " + new String(sharedKey2.getEncoded())
+ "as its DES session key");
}
}
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