Java加密算法(七)——非对称加密算法最高级ECC
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加密算法(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。 如果想要获得ECC算法实现,需要调用硬件完成加密/解密(ECC算法相当耗费资源,如果单纯使用CPU进行加密/解密,效率低下),涉及到Java Card领域,PKCS#11。其实,PKCS#11配置很简单,但缺乏硬件设备,无法尝试!
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加密算法(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 javax.crypto.NullCipher; import sun.security.ec.ECKeyFactory; import sun.security.ec.ECPrivateKeyImpl; import sun.security.ec.ECPublicKeyImpl; /** * ECC安全编码组件 * */ 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; } }
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。为了确保程序能够正常执行,我们使用了NullCipher类,验证程序。
再提供一个测试类:
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; /** * * ECC测试 */ 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); } }
控制台输出:
公钥: MEAwEAYHKoZIzj0CAQYFK4EEAAEDLAAEAv4TwFN7vBGsqgfXk95ObV5clO7oAokHD7BdOP9YMh8u gAU21TjM2qPZ 私钥: MDICAQAwEAYHKoZIzj0CAQYFK4EEAAEEGzAZAgEBBBTYJsR3BN7TFw7JHcAHFkwNmfil7w== 加密前: abc 解密后: abc
来源于:http://snowolf.iteye.com/blog
posted on 2013-03-25 16:49 restService 阅读(892) 评论(0) 编辑 收藏 举报