java对称加密和非对称加密(PBE、DH、RSA)

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1.       什么是对称式加密和非对称式加密

对称式加密:解密方式是加密方式的逆运算,即加密和解密使用的是同一个密钥(初等加密算法)。

非对称式加密:加密和解密需要两个密钥进行,这两个密钥是公钥和私钥(高等加密算法)。

2.       对称式加密和非对称式加密的主要实现方式

对称式加密主要实现方式:

1  DESDataEncryptionStandard):安全性较差,一般不建议使用。

2  3DES:三重DES,针对DES密钥长度较短的问题,3DES可以实现最少112位、最高168位密钥长度。

3  AES:相比于3DES拥有更好的安全性。

4  PBEPasswordBasedEncryption):基于口令的加密,结合了DESAES的优点。

非对称式加密主要实现方式:

1  DHDiffie-Hellman):密钥交换算法。

2  RSA:基于因子分解。

3  ElGamal:基于离散对数。

4  ECCEllipticalCurveCryptography):椭圆曲线加密。

3.       对称式加密和非对称式加密的对比

非对称加密与对称加密相比,其安全性更好:对称加密的通信双方使用相同的秘钥,如果一方的秘钥遭泄露,那么整个通信就会被破解。而非对称加密使用一对秘钥,一个用来加密,一个用来解密,而且公钥是公开的,秘钥是自己保存的,不需要像对称加密那样在通信之前要先同步密钥。

4.       对称式加密在Java中的实现(PBE加密):

[java]viewplaincopyprint?

1. public class PBE {  

2.     private static String src="security with PBE";  

3.     public static void main(String[] args){  

4.         jdkPBE();  

5.     }  

6.   

7.     public static void jdkPBE(){  

8.         try {  

9.             //初始化盐(扰码)  

10.            SecureRandom random=new SecureRandom();  

11.            byte[] salt=random.generateSeed(8);  

12.  

13.            //口令与密钥  

14.            String password="CSDN";  

15.            PBEKeySpec pbeKeySpec=new PBEKeySpec(password.toCharArray());  

16.            SecretKeyFactory factory=SecretKeyFactory.getInstance("PBEWITHMD5andEDS");  

17.            Key key=factory.generateSecret(pbeKeySpec);  

18.  

19.            //加密  

20.            PBEParameterSpec pbeParameterSpec=new PBEParameterSpec(salt,100);//参数1.盐,参数2.迭代次数  

21.            Cipher cipher=Cipher.getInstance("PBEWITHMD5andEDS");  

22.            cipher.init(Cipher.ENCRYPT_MODE,key,pbeParameterSpec);  

23.            byte[] result=cipher.doFinal(src.getBytes());  

24.            System.out.println("jdk pbe encrypt:" + Base64.encodeToString(result,1));  

25.  

26.            //解密  

27.            cipher.init(Cipher.DECRYPT_MODE,key,pbeParameterSpec);  

28.            result=cipher.doFinal(result);  

29.            System.out.println("jdk pbe decrypt:"+new String(result));  

30.        } catch (Exception e) {  

31.            e.printStackTrace();  

32.        }  

33.    }  

34.}  

public class PBE {

    private static Stringsrc="security with PBE";

    public static void main(String[]args){

        jdkPBE();

    }

 

    public static void jdkPBE(){

        try {

            //初始化盐(扰码)

            SecureRandom random=newSecureRandom();

            byte[]salt=random.generateSeed(8);

 

            //口令与密钥

            Stringpassword="CSDN";

            PBEKeySpecpbeKeySpec=new PBEKeySpec(password.toCharArray());

            SecretKeyFactoryfactory=SecretKeyFactory.getInstance("PBEWITHMD5andEDS");

            Keykey=factory.generateSecret(pbeKeySpec);

 

            //加密

            PBEParameterSpecpbeParameterSpec=new PBEParameterSpec(salt,100);//参数1.盐,参数2.迭代次数

            Cipher cipher=Cipher.getInstance("PBEWITHMD5andEDS");

           cipher.init(Cipher.ENCRYPT_MODE,key,pbeParameterSpec);

            byte[]result=cipher.doFinal(src.getBytes());

           System.out.println("jdk pbe encrypt:" +Base64.encodeToString(result,1));

 

            //解密

           cipher.init(Cipher.DECRYPT_MODE,key,pbeParameterSpec);

           result=cipher.doFinal(result);

           System.out.println("jdk pbe decrypt:"+new String(result));

        } catch (Exception e) {

            e.printStackTrace();

        }

    }

}

5.      非对称式加密在JAVA中的实现(DH加密):

[java]viewplaincopyprint?

1. public class DH {  

2.     private static String src="security with DH";  

3.     public static void main(String[] args){  

4.         jdkDH();  

5.     }  

6.   

7.     public static void jdkDH(){  

8.         try {  

9.             //初始化发送方密钥  

10.            KeyPairGenerator senderKeyPairGenerator=KeyPairGenerator.getInstance("DH");  

11.            senderKeyPairGenerator.initialize(512);  

12.            KeyPair senderKeyPair=senderKeyPairGenerator.generateKeyPair();  

13.            byte[] senderPublicKeyEnc=senderKeyPair.getPublic().getEncoded();  

14.  

15.            //初始化接收方密钥  

16.            KeyFactory receiverKeyFactory=KeyFactory.getInstance("DH");  

17.            X509EncodedKeySpec x509EncodedKeySpec=new X509EncodedKeySpec(senderPublicKeyEnc);  

18.            PublicKey receiverPublicKey=receiverKeyFactory.generatePublic(x509EncodedKeySpec);  

19.            DHParameterSpec dhParameterSpec=((DHPublicKey)receiverPublicKey).getParams();  

20.            KeyPairGenerator receiverKeyPairGenerator=KeyPairGenerator.getInstance("DH");  

21.            receiverKeyPairGenerator.initialize(dhParameterSpec);  

22.            KeyPair receiverKeyPair=receiverKeyPairGenerator.generateKeyPair();  

23.            PrivateKey receiverPrivateKey=receiverKeyPair.getPrivate();  

24.            byte[] receiverPublicKeyEnc =receiverKeyPair.getPublic().getEncoded();  

25.  

26.            //密钥构建  

27.            KeyAgreement receiverKeyAgreement = KeyAgreement.getInstance("DH");  

28.            receiverKeyAgreement.init(receiverPrivateKey);  

29.            receiverKeyAgreement.doPhase(receiverPublicKey, true);  

30.            SecretKey receiverDesKey=receiverKeyAgreement.generateSecret("DES");  

31.  

32.            KeyFactory senderKeyFactory=KeyFactory.getInstance("DH");  

33.            x509EncodedKeySpec=new X509EncodedKeySpec(receiverPublicKeyEnc);  

34.            PublicKey senderPublicKey=senderKeyFactory.generatePublic(x509EncodedKeySpec);  

35.            KeyAgreement senderKeyAgreement=KeyAgreement.getInstance("DH");  

36.            senderKeyAgreement.init(senderKeyPair.getPrivate());  

37.            senderKeyAgreement.doPhase(senderPublicKey, true);  

38.            SecretKey senderDesKey=senderKeyAgreement.generateSecret("DES");  

39.            if(Objects.equals(receiverDesKey,senderDesKey)){  

40.                System.out.println("双方密钥相同");  

41.            }  

42.  

43.            //加密  

44.            Cipher cipher=Cipher.getInstance("DES");  

45.            cipher.init(Cipher.ENCRYPT_MODE,senderDesKey);  

46.            byte[] result=cipher.doFinal(src.getBytes());  

47.            System.out.println("jdk dh encrypt:"+Base64.encodeToString(result,1));  

48.  

49.            //解密  

50.            cipher=Cipher.getInstance("DES");  

51.            cipher.init(Cipher.DECRYPT_MODE,receiverDesKey);  

52.            result=cipher.doFinal(result);  

53.            System.out.println("jdk dh encrypt:"+new String(result));  

54.  

55.        } catch (Exception e) {  

56.            e.printStackTrace();  

57.        }  

58.    }  

59.}  

public class DH {

    private static Stringsrc="security with DH";

    public static void main(String[]args){

        jdkDH();

    }

 

    public static void jdkDH(){

        try {

            //初始化发送方密钥

            KeyPairGeneratorsenderKeyPairGenerator=KeyPairGenerator.getInstance("DH");

           senderKeyPairGenerator.initialize(512);

            KeyPairsenderKeyPair=senderKeyPairGenerator.generateKeyPair();

            byte[]senderPublicKeyEnc=senderKeyPair.getPublic().getEncoded();

 

            //初始化接收方密钥

            KeyFactoryreceiverKeyFactory=KeyFactory.getInstance("DH");

            X509EncodedKeySpecx509EncodedKeySpec=new X509EncodedKeySpec(senderPublicKeyEnc);

            PublicKeyreceiverPublicKey=receiverKeyFactory.generatePublic(x509EncodedKeySpec);

            DHParameterSpecdhParameterSpec=((DHPublicKey)receiverPublicKey).getParams();

            KeyPairGeneratorreceiverKeyPairGenerator=KeyPairGenerator.getInstance("DH");

           receiverKeyPairGenerator.initialize(dhParameterSpec);

            KeyPairreceiverKeyPair=receiverKeyPairGenerator.generateKeyPair();

            PrivateKeyreceiverPrivateKey=receiverKeyPair.getPrivate();

            byte[]receiverPublicKeyEnc =receiverKeyPair.getPublic().getEncoded();

 

            //密钥构建

            KeyAgreementreceiverKeyAgreement = KeyAgreement.getInstance("DH");

           receiverKeyAgreement.init(receiverPrivateKey);

            receiverKeyAgreement.doPhase(receiverPublicKey,true);

            SecretKeyreceiverDesKey=receiverKeyAgreement.generateSecret("DES");

 

            KeyFactorysenderKeyFactory=KeyFactory.getInstance("DH");

            x509EncodedKeySpec=newX509EncodedKeySpec(receiverPublicKeyEnc);

            PublicKeysenderPublicKey=senderKeyFactory.generatePublic(x509EncodedKeySpec);

            KeyAgreementsenderKeyAgreement=KeyAgreement.getInstance("DH");

           senderKeyAgreement.init(senderKeyPair.getPrivate());

           senderKeyAgreement.doPhase(senderPublicKey, true);

            SecretKeysenderDesKey=senderKeyAgreement.generateSecret("DES");

           if(Objects.equals(receiverDesKey,senderDesKey)){

               System.out.println("双方密钥相同");

            }

 

            //加密

            Ciphercipher=Cipher.getInstance("DES");

           cipher.init(Cipher.ENCRYPT_MODE,senderDesKey);

            byte[]result=cipher.doFinal(src.getBytes());

           System.out.println("jdk dhencrypt:"+Base64.encodeToString(result,1));

 

            //解密

           cipher=Cipher.getInstance("DES");

           cipher.init(Cipher.DECRYPT_MODE,receiverDesKey);

           result=cipher.doFinal(result);

            System.out.println("jdk dhencrypt:"+new String(result));

 

        } catch (Exception e) {

            e.printStackTrace();

        }

    }

}

6.      非对称式加密在JAVA中的实现(RSA加密):

[java]viewplaincopyprint?

1. public class RSA {  

2.     private static String src="security with rsa";  

3.     public static void main(String[] args){  

4.         jdkRSA();  

5.     }  

6.   

7.     public static void jdkRSA(){  

8.         try {  

9.             //初始化密钥  

10.            KeyPairGenerator keyPairGenerator=KeyPairGenerator.getInstance("RSA");  

11.            keyPairGenerator.initialize(512);//64的整倍数,512~65536  

12.            KeyPair keyPair=keyPairGenerator.generateKeyPair();  

13.            RSAPrivateKey rsaPrivateKey= (RSAPrivateKey) keyPair.getPrivate();  

14.            RSAPublicKey rsaPublicKey= (RSAPublicKey) keyPair.getPublic();  

15.            System.out.println("Public key:"+ Base64.encodeToString(rsaPrivateKey.getEncoded(),1));  

16.            System.out.println("Private key:"+ Base64.encodeToString(rsaPrivateKey.getEncoded(),1));  

17.  

18.            //私钥加密,公钥解密——加密  

19.            PKCS8EncodedKeySpec pkcs8EncodedKeySpec=new PKCS8EncodedKeySpec(rsaPrivateKey.getEncoded());  

20.            KeyFactory keyFactory=KeyFactory.getInstance("RSA");  

21.            PrivateKey privateKey=keyFactory.generatePrivate(pkcs8EncodedKeySpec);  

22.            Cipher cipher=Cipher.getInstance("RSA");  

23.            cipher.init(Cipher.ENCRYPT_MODE, privateKey);  

24.            byte[] result=cipher.doFinal(src.getBytes());  

25.            System.out.println("私钥加密,公钥解密——加密:"+Base64.encodeToString(result,1));  

26.  

27.            //私钥加密,公钥解密——解密  

28.            X509EncodedKeySpec x509EncodedKeySpec=new X509EncodedKeySpec(rsaPublicKey.getEncoded());  

29.            keyFactory=KeyFactory.getInstance("RSA");  

30.            PublicKey publicKey=keyFactory.generatePublic(x509EncodedKeySpec);  

31.            cipher=Cipher.getInstance("RSA");  

32.            cipher.init(Cipher.DECRYPT_MODE,publicKey);  

33.            result=cipher.doFinal(result);  

34.            System.out.println(new String(result));  

35.  

36.            //公钥加密,私钥解密——加密  

37.            x509EncodedKeySpec=new X509EncodedKeySpec(rsaPublicKey.getEncoded());  

38.            keyFactory=KeyFactory.getInstance("RSA");  

39.            publicKey=keyFactory.generatePublic(x509EncodedKeySpec);  

40.            cipher=Cipher.getInstance("RSA");  

41.            cipher.init(Cipher.ENCRYPT_MODE,publicKey);  

42.            result=cipher.doFinal(src.getBytes());  

43.            System.out.println("钥加密,私钥解密——加密:"+Base64.encodeToString(result,1));  

44.  

45.            //公钥加密,私钥解密——解密  

46.            pkcs8EncodedKeySpec=new PKCS8EncodedKeySpec(rsaPrivateKey.getEncoded());  

47.            keyFactory=KeyFactory.getInstance("RSA");  

48.            privateKey=keyFactory.generatePrivate(pkcs8EncodedKeySpec);  

49.            cipher=Cipher.getInstance("RSA");  

50.            cipher.init(Cipher.DECRYPT_MODE,privateKey);  

51.            cipher.doFinal(result);  

52.            System.out.println("公钥加密,私钥解密——解密:" + Base64.encodeToString(result, 1));  

53.  

54.        } catch (Exception e) {  

55.            e.printStackTrace();  

56.        }  

57.    }  

58.}  

public class RSA {

    private static Stringsrc="security with rsa";

    public static void main(String[]args){

        jdkRSA();

    }

 

    public static void jdkRSA(){

        try {

            //初始化密钥

            KeyPairGeneratorkeyPairGenerator=KeyPairGenerator.getInstance("RSA");

           keyPairGenerator.initialize(512);//64的整倍数,512~65536

            KeyPairkeyPair=keyPairGenerator.generateKeyPair();

            RSAPrivateKeyrsaPrivateKey= (RSAPrivateKey) keyPair.getPrivate();

            RSAPublicKeyrsaPublicKey= (RSAPublicKey) keyPair.getPublic();

           System.out.println("Public key:"+Base64.encodeToString(rsaPrivateKey.getEncoded(),1));

           System.out.println("Private key:"+ Base64.encodeToString(rsaPrivateKey.getEncoded(),1));

 

            //私钥加密,公钥解密——加密

            PKCS8EncodedKeySpecpkcs8EncodedKeySpec=new PKCS8EncodedKeySpec(rsaPrivateKey.getEncoded());

            KeyFactorykeyFactory=KeyFactory.getInstance("RSA");

            PrivateKeyprivateKey=keyFactory.generatePrivate(pkcs8EncodedKeySpec);

            Ciphercipher=Cipher.getInstance("RSA");

           cipher.init(Cipher.ENCRYPT_MODE, privateKey);

            byte[]result=cipher.doFinal(src.getBytes());

            System.out.println("私钥加密,公钥解密——加密:"+Base64.encodeToString(result,1));

 

            //私钥加密,公钥解密——解密

            X509EncodedKeySpecx509EncodedKeySpec=new X509EncodedKeySpec(rsaPublicKey.getEncoded());

           keyFactory=KeyFactory.getInstance("RSA");

            PublicKeypublicKey=keyFactory.generatePublic(x509EncodedKeySpec);

           cipher=Cipher.getInstance("RSA");

           cipher.init(Cipher.DECRYPT_MODE,publicKey);

           result=cipher.doFinal(result);

            System.out.println(newString(result));

 

            //公钥加密,私钥解密——加密

            x509EncodedKeySpec=newX509EncodedKeySpec(rsaPublicKey.getEncoded());

           keyFactory=KeyFactory.getInstance("RSA");

           publicKey=keyFactory.generatePublic(x509EncodedKeySpec);

           cipher=Cipher.getInstance("RSA");

           cipher.init(Cipher.ENCRYPT_MODE,publicKey);

           result=cipher.doFinal(src.getBytes());

           System.out.println("钥加密,私钥解密——加密:"+Base64.encodeToString(result,1));

 

            //公钥加密,私钥解密——解密

            pkcs8EncodedKeySpec=newPKCS8EncodedKeySpec(rsaPrivateKey.getEncoded());

           keyFactory=KeyFactory.getInstance("RSA");

           privateKey=keyFactory.generatePrivate(pkcs8EncodedKeySpec);

            cipher=Cipher.getInstance("RSA");

           cipher.init(Cipher.DECRYPT_MODE,privateKey);

            cipher.doFinal(result);

           System.out.println("公钥加密,私钥解密——解密:" + Base64.encodeToString(result, 1));

 

        } catch (Exception e) {

            e.printStackTrace();

        }

    }

}


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