import java.math.BigInteger;
import java.security.Key;
import java.security.KeyFactory;
import java.security.interfaces.ECPrivateKey;
import java.security.interfaces.ECPublicKey;
import java.security.spec.ECFieldF2m;
import java.security.spec.ECParameterSpec;
import java.security.spec.ECPoint;
import java.security.spec.ECPrivateKeySpec;
import java.security.spec.ECPublicKeySpec;
import java.security.spec.EllipticCurve;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.HashMap;
import java.util.Map;
import javax.crypto.Cipher;
import javax.crypto.NullCipher;
import sun.security.ec.ECKeyFactory;
import sun.security.ec.ECPrivateKeyImpl;
import sun.security.ec.ECPublicKeyImpl;
/**
 * ECC安全編碼組件
 * 
 * @author 梁棟
 * @version 1.0
 * @since 1.0
 */
public abstract class ECCCoder extends Coder {
  public static final String ALGORITHM = "EC";
  private static final String PUBLIC_KEY = "ECCPublicKey";
  private static final String PRIVATE_KEY = "ECCPrivateKey";
  /**
   * 解密<br>
   * 用私鑰解密
   * 
   * @param data
   * @param key
   * @return
   * @throws Exception
   */
  public static byte[] decrypt(byte[] data, String key) throws Exception {
    // 對(duì)密鑰解密
    byte[] keyBytes = decryptBASE64(key);
    // 取得私鑰
    PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
    KeyFactory keyFactory = ECKeyFactory.INSTANCE;
    ECPrivateKey priKey = (ECPrivateKey) keyFactory
        .generatePrivate(pkcs8KeySpec);
    ECPrivateKeySpec ecPrivateKeySpec = new ECPrivateKeySpec(priKey.getS(),
        priKey.getParams());
    // 對(duì)數(shù)據(jù)解密
    // TODO Chipher不支持EC算法 未能實(shí)現(xiàn)
    Cipher cipher = new NullCipher();
    // Cipher.getInstance(ALGORITHM, keyFactory.getProvider());
    cipher.init(Cipher.DECRYPT_MODE, priKey, ecPrivateKeySpec.getParams());
    return cipher.doFinal(data);
  }
  /**
   * 加密<br>
   * 用公鑰加密
   * 
   * @param data
   * @param privateKey
   * @return
   * @throws Exception
   */
  public static byte[] encrypt(byte[] data, String privateKey)
      throws Exception {
    // 對(duì)公鑰解密
    byte[] keyBytes = decryptBASE64(privateKey);
    // 取得公鑰
    X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);
    KeyFactory keyFactory = ECKeyFactory.INSTANCE;
    ECPublicKey pubKey = (ECPublicKey) keyFactory
        .generatePublic(x509KeySpec);
    ECPublicKeySpec ecPublicKeySpec = new ECPublicKeySpec(pubKey.getW(),
        pubKey.getParams());
    // 對(duì)數(shù)據(jù)加密
    // TODO Chipher不支持EC算法 未能實(shí)現(xiàn)
    Cipher cipher = new NullCipher();
    // Cipher.getInstance(ALGORITHM, keyFactory.getProvider());
    cipher.init(Cipher.ENCRYPT_MODE, pubKey, ecPublicKeySpec.getParams());
    return cipher.doFinal(data);
  }
  /**
   * 取得私鑰
   * 
   * @param keyMap
   * @return
   * @throws Exception
   */
  public static String getPrivateKey(Map<String, Object> keyMap)
      throws Exception {
    Key key = (Key) keyMap.get(PRIVATE_KEY);
    return encryptBASE64(key.getEncoded());
  }
  /**
   * 取得公鑰
   * 
   * @param keyMap
   * @return
   * @throws Exception
   */
  public static String getPublicKey(Map<String, Object> keyMap)
      throws Exception {
    Key key = (Key) keyMap.get(PUBLIC_KEY);
    return encryptBASE64(key.getEncoded());
  }
  /**
   * 初始化密鑰
   * 
   * @return
   * @throws Exception
   */
  public static Map<String, Object> initKey() throws Exception {
    BigInteger x1 = new BigInteger(
        "2fe13c0537bbc11acaa07d793de4e6d5e5c94eee8", 16);
    BigInteger x2 = new BigInteger(
        "289070fb05d38ff58321f2e800536d538ccdaa3d9", 16);
    ECPoint g = new ECPoint(x1, x2);
    // the order of generator
    BigInteger n = new BigInteger(
        "5846006549323611672814741753598448348329118574063", 10);
    // the cofactor
    int h = 2;
    int m = 163;
    int[] ks = { 7, 6, 3 };
    ECFieldF2m ecField = new ECFieldF2m(m, ks);
    // y^2+xy=x^3+x^2+1
    BigInteger a = new BigInteger("1", 2);
    BigInteger b = new BigInteger("1", 2);
    EllipticCurve ellipticCurve = new EllipticCurve(ecField, a, b);
    ECParameterSpec ecParameterSpec = new ECParameterSpec(ellipticCurve, g,
        n, h);
    // 公鑰
    ECPublicKey publicKey = new ECPublicKeyImpl(g, ecParameterSpec);
    BigInteger s = new BigInteger(
        "1234006549323611672814741753598448348329118574063", 10);
    // 私鑰
    ECPrivateKey privateKey = new ECPrivateKeyImpl(s, ecParameterSpec);
    Map<String, Object> keyMap = new HashMap<String, Object>(2);
    keyMap.put(PUBLIC_KEY, publicKey);
    keyMap.put(PRIVATE_KEY, privateKey);
    return keyMap;
  }
}

import static org.junit.Assert.*;
import java.math.BigInteger;
import java.security.spec.ECFieldF2m;
import java.security.spec.ECParameterSpec;
import java.security.spec.ECPoint;
import java.security.spec.ECPrivateKeySpec;
import java.security.spec.ECPublicKeySpec;
import java.security.spec.EllipticCurve;
import java.util.Map;
import org.junit.Test;
/**
 * 
 * @author 梁棟
 * @version 1.0
 * @since 1.0
 */
public class ECCCoderTest {
  @Test
  public void test() throws Exception {
    String inputStr = "abc";
    byte[] data = inputStr.getBytes();
    Map<String, Object> keyMap = ECCCoder.initKey();
    String publicKey = ECCCoder.getPublicKey(keyMap);
    String privateKey = ECCCoder.getPrivateKey(keyMap);
    System.err.println("公鑰: \n" + publicKey);
    System.err.println("私鑰： \n" + privateKey);
    byte[] encodedData = ECCCoder.encrypt(data, publicKey);
    byte[] decodedData = ECCCoder.decrypt(encodedData, privateKey);
    String outputStr = new String(decodedData);
    System.err.println("加密前: " + inputStr + "\n\r" + "解密后: " + outputStr);
    assertEquals(inputStr, outputStr);
  }
}

公鑰: 
MEAwEAYHKoZIzj0CAQYFK4EEAAEDLAAEAv4TwFN7vBGsqgfXk95ObV5clO7oAokHD7BdOP9YMh8u
gAU21TjM2qPZ
私鑰： 
MDICAQAwEAYHKoZIzj0CAQYFK4EEAAEEGzAZAgEBBBTYJsR3BN7TFw7JHcAHFkwNmfil7w==
加密前: abc
解密后: abc