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© 张超超 黑马帝   /  2012-4-1 11:44  /  3317 人查看  /  5 人回复  /   0 人收藏 转载请遵从CC协议 禁止商业使用本文

谁能给详细谈谈java程序的加密技术,最好能带实例。

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 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。

  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:

  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

  *

  * @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


  * 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


  * 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 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 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 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 keyMap = new HashMap(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。

  照旧提供一个测试类:

  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 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
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是自己总结的吗?》是自己总结的就好了
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我是学信息安全的,求指导啊!太牛了
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翟友伟 发表于 2012-4-1 15:51
是自己总结的吗?》是自己总结的就好了

哥得分你羡慕了,还要拆穿我!
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