Java加密算法 RSA详解编程语言

公钥加密也称为非对称加密、速度慢、加密和解密的钥匙不相同，某一个人持有私钥，任何人都可以知道公钥

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 公钥加密 非对称加密  
 * @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("斯柯达U*(Sfsad7f()*^%%$");   
        method2("斯柯达U*(Sfsad7f()*^%%$");   
        method3("斯柯达U*(Sfsad7f()*^%%$");   
           
    }   
       
    /**  
     * 公钥加密，私钥解密    使用默认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); //公钥加密   
        byte[] encrypt = cipher.doFinal(str.getBytes());   
        System.out.println("公钥加密后1：" + Arrays.toString(encrypt));   
           
        cipher.init(Cipher.DECRYPT_MODE, privateKey);//私钥解密   
        byte[] decrypt = cipher.doFinal(encrypt);   
        System.out.println("私钥解密后1：" + new String(decrypt));   
    }   
       
    /**  
     * 私钥加密，公钥解密    使用默认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); //私钥加密   
        byte[] encrypt = cipher.doFinal(str.getBytes());   
        System.out.println("私钥加密后2：" + Arrays.toString(encrypt));   
           
        cipher.init(Cipher.DECRYPT_MODE, publicKey);//公钥解密   
        byte[] decrypt = cipher.doFinal(encrypt);   
        System.out.println("公钥解密后2：" + new String(decrypt));   
    }   
       
    /**  
     * 私钥加密，公钥解密    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); //私钥加密   
        byte[] encrypt = cipher.doFinal(str.getBytes());   
        System.out.println("私钥加密后3：" + Arrays.toString(encrypt));   
           
        cipher.init(Cipher.DECRYPT_MODE, publicKey);//公钥解密   
        byte[] decrypt = cipher.doFinal(encrypt);   
        System.out.println("公钥解密后3：" + new String(decrypt));   
    }   
}