25、Java加密技术（七）——非对称加密算法最高级ECC

<转>http://snowolf.iteye.com/blog/383412
ECC
ECC-Elliptic Curves Cryptography，椭圆曲线密码编码学，是目前已知的公钥体制中，对每比特所提供加密强度最高的一种体制。在软件注册保护方面起到很大的作用，一般的序列号通常由该算法产生。
java代码实现如下：
###：可能无法正确加载sun.security.ec.*；把右侧【libraries中的JRE System Library】删除重新导入；

package org.nick.encrypt;

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.*;
  

  
/** 
 * ECC安全编码组件 
 * @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> 
     * 用私钥解密 
     *  
     * @param data 
     * @param key 
     * @return 
     * @throws Exception 
     */  
    public static byte[] decrypt(byte[] data, String key) throws Exception {  
        // 对密钥解密  
        byte[] keyBytes = decryptBASE64(key);  
  
        // 取得私钥  
        PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);  
        KeyFactory keyFactory = ECKeyFactory.INSTANCE;  
  
        ECPrivateKey priKey = (ECPrivateKey) keyFactory  
                .generatePrivate(pkcs8KeySpec);  
  
        ECPrivateKeySpec ecPrivateKeySpec = new ECPrivateKeySpec(priKey.getS(),  
                priKey.getParams());  
  
        // 对数据解密  
        // TODO Chipher不支持EC算法 未能实现  
        Cipher cipher = new NullCipher();  
        // Cipher.getInstance(ALGORITHM, keyFactory.getProvider());  
        cipher.init(Cipher.DECRYPT_MODE, priKey, ecPrivateKeySpec.getParams());  
  
        return cipher.doFinal(data);  
    }  
  
    /** 
     * 加密<br> 
     * 用公钥加密 
     *  
     * @param data 
     * @param privateKey 
     * @return 
     * @throws Exception 
     */  
    public static byte[] encrypt(byte[] data, String privateKey)  
            throws Exception {  
        // 对公钥解密  
        byte[] keyBytes = decryptBASE64(privateKey);  
  
        // 取得公钥  
        X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);  
        KeyFactory keyFactory = ECKeyFactory.INSTANCE;  
  
        ECPublicKey pubKey = (ECPublicKey) keyFactory  
                .generatePublic(x509KeySpec);  
  
        ECPublicKeySpec ecPublicKeySpec = new ECPublicKeySpec(pubKey.getW(),  
                pubKey.getParams());  
  
        // 对数据加密  
        // TODO Chipher不支持EC算法 未能实现  
        Cipher cipher = new NullCipher();  
        // Cipher.getInstance(ALGORITHM, keyFactory.getProvider());  
        cipher.init(Cipher.ENCRYPT_MODE, pubKey, ecPublicKeySpec.getParams());  
  
        return cipher.doFinal(data);  
    }  
  
    /** 
     * 取得私钥 
     *  
     * @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());  
    }  
  
    /** 
     * 取得公钥 
     *  
     * @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());  
    }  
  
    /** 
     * 初始化密钥 
     *  
     * @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);  
        // 公钥  
        ECPublicKey publicKey = new ECPublicKeyImpl(g, ecParameterSpec);  
  
        BigInteger s = new BigInteger(  
                "1234006549323611672814741753598448348329118574063", 10);  
        // 私钥  
        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;  
    }  
  
}  

Chipher不支持EC算法 ，以上代码仅供参考。Chipher、Signature、KeyPairGenerator、KeyAgreement、SecretKey均不支持EC算法。为了确保程序能够正常执行，我们使用了NullCipher类，验证程序。

import java.math.BigInteger;
import java.util.Map;

import org.nick.encrypt.Coder;
import org.nick.encrypt.DESCoder;
import org.nick.encrypt.DHCoder;
import org.nick.encrypt.DSACoder;
import org.nick.encrypt.ECCCoder;
import org.nick.encrypt.PBECoder;
import org.nick.encrypt.RSACoder;
public class Test
{
   
    public static void main(String[] str) 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("公钥: \n" + publicKey);  
         System.err.println("私钥： \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);  
    }
}

公钥:
MEAwEAYHKoZIzj0CAQYFK4EEAAEDLAAEAv4TwFN7vBGsqgfXk95ObV5clO7oAokHD7BdOP9YMh8u
gAU21TjM2qPZ

私钥：
MDICAQAwEAYHKoZIzj0CAQYFK4EEAAEEGzAZAgEBBBTYJsR3BN7TFw7JHcAHFkwNmfil7w==

加密前: abc

解密后: abc