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Java(110)：非对称加密RSA的使用(KeyPair生成密钥)

RSA 算法是一种非对称加解密算法。服务方生成一对 RSA 密钥，即公钥 + 私钥，将公钥提供给调用方，调用方使用公钥对数据进行加密后，服务方根据私钥进行解密。

1、RSA生成密钥方法

        keyPairGen.initialize(1024);//生成"密钥对"对象KeyPair keyPair = keyPairGen.generateKeyPair();//分别获取私钥和公钥对象RSAPrivateKey PrivateKey =(RSAPrivateKey) keyPair.getPrivate();RSAPublicKey publicKey =(RSAPublicKey) keyPair.getPublic();

2、RSA加密和解密方法

   /*** 公钥加密* @param publicKey 公钥* @param obj 明文* @return byte[] 密文*/public static byte[] encrypt(RSAPublicKey publicKey, byte[] obj) throws Exception {Cipher cipher =Cipher.getInstance("RSA");cipher.init(Cipher.ENCRYPT_MODE,publicKey);//返回加密后的内容return cipher.doFinal(obj);}/*** 私钥解密* @param privateKey 公钥* @param obj 密文* @return byte[] 密文*/public static byte[] decrypt(RSAPrivateKey privateKey, byte[] obj)throws Exception {Cipher cipher = Cipher.getInstance("RSA");cipher.init(Cipher.DECRYPT_MODE, privateKey);//返回解密后的数组return cipher.doFinal(obj);}

3、Base64编码和解码

maven

<dependency><groupId>commons-codec</groupId><artifactId>commons-codec</artifactId><version>1.11</version>
</dependency>

    /*** 编码* @param txt byte字节数组* @return encode Base64编码*/public static byte[] encode(byte[] txt) {return org.apache.commons.codec.binary.Base64.encodeBase64(txt);}/*** 解码* @param txt 编码后的byte* @return decode Base64解码*/public static byte[] decode(String txt){return org.apache.commons.codec.binary.Base64.decodeBase64(txt);}

4、调用加解密

    public static void main(String[] args)throws Exception {//获取RSA算法的密钥生成器对象KeyPairGenerator keyPairGen =KeyPairGenerator.getInstance("RSA");//设定密钥长度为1024位keyPairGen.initialize(1024);//生成"密钥对"对象KeyPair keyPair = keyPairGen.generateKeyPair();//分别获取私钥和公钥对象RSAPrivateKey PrivateKey =(RSAPrivateKey) keyPair.getPrivate();RSAPublicKey publicKey =(RSAPublicKey) keyPair.getPublic();//执行加密和解密过程String InData="Hello World!";//得到要加密内容的数组byte[] byteInData =InData.getBytes("UTF-8");//用公钥加密byte[] cipherByte= encrypt(publicKey,byteInData);  //RSA加密String cipher=new String(encode(cipherByte));   //Base64a编码System.out.println("公钥加密，密文："+cipher);//用私钥解密byte[] plain =decrypt(PrivateKey,decode(cipher)); //Base64a解码System.out.println("私钥解密，明文："+new String(plain)); //RSA解密}

5、RSA加解密代码示例：

package jmj;import javax.crypto.Cipher;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;/*** Description :** @author : HMF* Date : Created in 20:32 2023/3/13* @version :*/
public class RSATest {public static void main(String[] args)throws Exception {//获取RSA算法的密钥生成器对象KeyPairGenerator keyPairGen =KeyPairGenerator.getInstance("RSA");//设定密钥长度为1024位keyPairGen.initialize(1024);//生成"密钥对"对象KeyPair keyPair = keyPairGen.generateKeyPair();//分别获取私钥和公钥对象RSAPrivateKey PrivateKey =(RSAPrivateKey) keyPair.getPrivate();RSAPublicKey publicKey =(RSAPublicKey) keyPair.getPublic();//执行加密和解密过程String InData="Hello World!";//得到要加密内容的数组byte[] byteInData =InData.getBytes("UTF-8");//用公钥加密byte[] cipherByte= encrypt(publicKey,byteInData);  //RSA加密String cipher=new String(encode(cipherByte));   //Base64a编码System.out.println("公钥加密，密文："+cipher);//用私钥解密byte[] plain =decrypt(PrivateKey,decode(cipher)); //Base64a解码System.out.println("私钥解密，明文："+new String(plain)); //RSA解密}/*** 编码* @param txt byte字节数组* @return encode Base64编码*/public static byte[] encode(byte[] txt) {return org.apache.commons.codec.binary.Base64.encodeBase64(txt);}/*** 解码* @param txt 编码后的byte* @return decode Base64解码*/public static byte[] decode(String txt){return org.apache.commons.codec.binary.Base64.decodeBase64(txt);}/*** 公钥加密* @param publicKey 公钥* @param obj 明文* @return byte[] 密文*/public static byte[] encrypt(RSAPublicKey publicKey, byte[] obj) throws Exception {Cipher cipher =Cipher.getInstance("RSA");cipher.init(Cipher.ENCRYPT_MODE,publicKey);//返回加密后的内容return cipher.doFinal(obj);}/*** 私钥解密* @param privateKey 公钥* @param obj 密文* @return byte[] 密文*/public static byte[] decrypt(RSAPrivateKey privateKey, byte[] obj)throws Exception {Cipher cipher = Cipher.getInstance("RSA");cipher.init(Cipher.DECRYPT_MODE, privateKey);//返回解密后的数组return cipher.doFinal(obj);}}

执行结果：

 

参考：https://blog.csdn.net/piaoranyuji/article/details/126140261