為什么我的運行結(jié)果完全不同?

package _ELGamal;

import java.security.AlgorithmParameterGenerator;
import java.security.AlgorithmParameters;
import java.security.InvalidAlgorithmParameterException;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.NoSuchAlgorithmException;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.SecureRandom;
import java.security.Security;
import java.security.spec.InvalidParameterSpecException;

import javax.crypto.spec.DHParameterSpec;

import org.apache.commons.codec.binary.Base64;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
import org.bouncycastle.jce.spec.*;

public class ELGamal {
?? ?
?? ?private static String ELGamal="xgqfrms";
?? ?private static String str1,str2;
?? ?public static void main(String[] args) throws Exception {
?? ??? ?// TODO Auto-generated method stub
?? ??? ?MyELGamal();
?? ?}
?? ?
?? ?public static void MyELGamal() throws Exception{
?? ??? ???? Security.addProvider(new BouncyCastleProvider());
?? ??? ?
?? ??? ??? ?AlgorithmParameterGenerator apg = AlgorithmParameterGenerator.getInstance(ELGamal);
?? ??? ??? ?apg.init(256);
?? ??? ??? ?AlgorithmParameters ap = apg.generateParameters();
?? ??? ??? ?DHParameterSpec dhps = (DHParameterSpec)ap.getParameterSpec(DHParameterSpec.class);
?? ??? ??? ?KeyPairGenerator kpg = KeyPairGenerator.getInstance(ELGamal);
?? ??? ??? ?kpg.initialize(dhps,new SecureRandom());
?? ??? ??? ?KeyPair kp = kpg.generateKeyPair();
?? ??? ??? ?PublicKey puk = kp.getPublic();
?? ??? ??? ?PrivateKey prk = kp.getPrivate();
?? ??? ??? ?str1 = "Public Key:"+Base64.encodeBase64String(puk.getEncoded());
?? ??? ??? ?str2 = "Private Key:"+Base64.encodeBase64String(prk.getEncoded());
?? ??? ??? ?System.out.println(str1);
?? ??? ??? ?System.out.println(str2);
?? ??? ??? ?
?? ??? ?
??? }
}

error info:

Exception in thread "main" java.security.NoSuchAlgorithmException: xgqfrms AlgorithmParameterGenerator not available
?? ?at sun.security.jca.GetInstance.getInstance(Unknown Source)
?? ?at java.security.Security.getImpl(Unknown Source)
?? ?at java.security.AlgorithmParameterGenerator.getInstance(Unknown Source)
?? ?at _ELGamal.ELGamal.MyELGamal(ELGamal.java:33)
?? ?at _ELGamal.ELGamal.main(ELGamal.java:27)