Java加密算法 RSA

公鑰加密也稱為非對稱加密、速度慢、加密和解密的鑰匙不相同，某一個人持有私鑰，任何人都可以知道公鑰

import java.security.KeyPair;

import java.security.KeyPairGenerator;

import java.security.PrivateKey;

import java.security.PublicKey;

import java.util.Arrays;

import javax.crypto.Cipher;
/**

RSA算法 公鑰加密 非對稱加密 
@author stone 
@date 2014-03-11 00:28:38 
*/

public class RSA {

 public static final String KEY_ALGORITHM = "RSA";

 public static final String CIPHER_ALGORITHM_ECB1 = "RSA/ECB/PKCS1Padding";

 public static final String CIPHER_ALGORITHM_ECB2 = "RSA/ECB/OAEPWithSHA-1AndMGF1Padding"; //不能用

 public static final String CIPHER_ALGORITHM_ECB3 = "OAEPWithSHA-256AndMGF1Padding"; //不能用
static PublicKey publicKey;

 static PrivateKey privateKey;

 static Cipher cipher;

 static KeyPair keyPair;
public static void main(String[] args) throws Exception {

 method1("斯柯達U*(Sfsad7f()*^%%$");  
 method2("斯柯達U*(Sfsad7f()*^%%$");  
 method3("斯柯達U*(Sfsad7f()*^%%$");  


}
/**

公鑰加密，私鑰解密    使用默認CIPHER_ALGORITHM_ECB1 
@param str 
@throws Exception 
*/

static void method1(String str) throws Exception {

 KeyPairGenerator keyGenerator = KeyPairGenerator.getInstance(KEY_ALGORITHM);

 KeyPair keyPair = keyGenerator.generateKeyPair();

 publicKey = keyPair.getPublic();

 privateKey = keyPair.getPrivate();

 cipher = Cipher.getInstance(KEY_ALGORITHM);

 cipher.init(Cipher.ENCRYPT_MODE, publicKey); //公鑰加密

 byte[] encrypt = cipher.doFinal(str.getBytes());

 System.out.println("公鑰加密后1：" + Arrays.toString(encrypt));
cipher.init(Cipher.DECRYPT_MODE, privateKey);//私鑰解密

 byte[] decrypt = cipher.doFinal(encrypt);

 System.out.println("私鑰解密后1：" + new String(decrypt));

}
/**

私鑰加密，公鑰解密    使用默認CIPHER_ALGORITHM_ECB1 
@param str 
@throws Exception 
*/

static void method2(String str) throws Exception {

 KeyPairGenerator keyGenerator = KeyPairGenerator.getInstance(KEY_ALGORITHM);

 KeyPair keyPair = keyGenerator.generateKeyPair();

 publicKey = keyPair.getPublic();

 privateKey = keyPair.getPrivate();

 cipher = Cipher.getInstance(KEY_ALGORITHM);

 cipher.init(Cipher.ENCRYPT_MODE, privateKey); //私鑰加密

 byte[] encrypt = cipher.doFinal(str.getBytes());

 System.out.println("私鑰加密后2：" + Arrays.toString(encrypt));
cipher.init(Cipher.DECRYPT_MODE, publicKey);//公鑰解密

 byte[] decrypt = cipher.doFinal(encrypt);

 System.out.println("公鑰解密后2：" + new String(decrypt));

}
/**

私鑰加密，公鑰解密    使用CIPHER_ALGORITHM_ECB1 = RSA/ECB/PKCS1Padding 
@param str 
@throws Exception 
*/

static void method3(String str) throws Exception {

 KeyPairGenerator keyGenerator = KeyPairGenerator.getInstance(KEY_ALGORITHM);

 KeyPair keyPair = keyGenerator.generateKeyPair();

 publicKey = keyPair.getPublic();

 privateKey = keyPair.getPrivate();

 cipher = Cipher.getInstance(CIPHER_ALGORITHM_ECB1);

 cipher.init(Cipher.ENCRYPT_MODE, privateKey); //私鑰加密

 byte[] encrypt = cipher.doFinal(str.getBytes());

 System.out.println("私鑰加密后3：" + Arrays.toString(encrypt));
cipher.init(Cipher.DECRYPT_MODE, publicKey);//公鑰解密

 byte[] decrypt = cipher.doFinal(encrypt);

 System.out.println("公鑰解密后3：" + new String(decrypt));

}

}  </pre>