JAVA加密算法7

关键字: ecc, 椭圆曲线加密, 非对称加密
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。
    当我开始整理《Java加密技术（二）》的时候，我就已经在开始研究ECC了，但是关于Java实现ECC算法的资料实在是太少了，无论是国内还是国外的资料，无论是官方还是非官方的解释，最终只有一种答案——ECC算法在jdk1.5后加入支持，目前仅仅只能完成密钥的生成与解析，对于通过密钥对数据进行处理的java实现仅在javacard项目中使用。 这已经是另一个领域了，完全跳出了J2SE的范畴，我就不再继续追根溯源了。
    尽管如此，我照旧提供相应的Java实现代码，以供大家参考。
    通过java代码实现如下：Coder类见 java加密技术（一）
Java代码
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 sun.security.ec.ECKeyFactory;  
import sun.security.ec.ECPrivateKeyImpl;  
import sun.security.ec.ECPublicKeyImpl;  
 
/** 
* ECC安全编码组件 
*  
* @author 梁栋 
* @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;  
        Key privateKey = keyFactory.generatePrivate(pkcs8KeySpec);  
 
        ECPrivateKey priKey = (ECPrivateKey) privateKey;  
 
        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 = 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;  
        Key publicKey = keyFactory.generatePublic(x509KeySpec);  
 
        ECPublicKey pubKey = (ECPublicKey) publicKey;  
 
        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 = 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;  
    }  
 
} 

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 sun.security.ec.ECKeyFactory;
import sun.security.ec.ECPrivateKeyImpl;
import sun.security.ec.ECPublicKeyImpl;

/**
* ECC安全编码组件
*
* @author 梁栋
* @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;
Key privateKey = keyFactory.generatePrivate(pkcs8KeySpec);

ECPrivateKey priKey = (ECPrivateKey) privateKey;

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 = 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;
Key publicKey = keyFactory.generatePublic(x509KeySpec);

ECPublicKey pubKey = (ECPublicKey) publicKey;

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 = 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;
}

}


    请注意上述代码中的TODO内容，再次提醒注意，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。

照旧提供一个测试类：
Java代码
 
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 梁栋 
* @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);  
        assertEquals(inputStr, outputStr);  
    }  
} 


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 梁栋
* @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);
assertEquals(inputStr, outputStr);
}
}