Java笔记-非对称加密RSA的使用

Posted 2021-09-07 IT1995

使用OpenSSL生成对应RSA私钥和RSA公钥：

#rsa私钥：
genrsa -out rsa_private_key.pem 1024
pkcs8 -topk8 -inform PEM -in rsa_private_key.pem -outform pem -nocrypt -out rsa_private_key_8.pem
#rsa公钥：
rsa -in rsa_private_key_8.pem -pubout -out rsa_public_key.pem

Base64使用的是这样Maven

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

这里生成的公钥和私钥是Base64的，如下：

 公钥：

 

所以用的时候需要先用base64解密。

使用逻辑是这样的，先那这些密钥进行Base64解密。

在用公钥给内容加密，用私钥解密：

Base64相关的代码：

DataSecret.java

package cn.it1995.tool;

import org.apache.commons.codec.binary.Base64;

import java.io.UnsupportedEncodingException;

public class DataSecret {


    public static byte[] encode(byte[] txt) throws UnsupportedEncodingException {

        return Base64.encodeBase64(txt);
    }

    public static byte[] decode(String txt){

        return Base64.decodeBase64(txt);
    }
}

RSA.java

package cn.it1995.tool;

import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import java.io.UnsupportedEncodingException;
import java.security.InvalidKeyException;
import java.security.KeyFactory;
import java.security.NoSuchAlgorithmException;
import java.security.interfaces.RSAPrivateCrtKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;

public class RSA {

    private static final String RSA_ALGORITHM = "RSA/ECB/PKCS1Padding";

    //加密回的是base64
    public static String encrypt(String data, String key) throws UnsupportedEncodingException {

        String message = data;
        byte[] decode = DataSecret.decode(key);
        byte[] result = new byte[]{0};

        try {

            RSAPublicKey publicKey = (RSAPublicKey) KeyFactory.getInstance("RSA")
                    .generatePublic(new X509EncodedKeySpec(decode));
            Cipher cipher = Cipher.getInstance(RSA_ALGORITHM);
            cipher.init(Cipher.ENCRYPT_MODE, publicKey);
            result = cipher.doFinal(message.getBytes("UTF-8"));
        }
        catch (NoSuchAlgorithmException e) {

            e.printStackTrace();
        }
        catch (InvalidKeySpecException e) {

            e.printStackTrace();
        }
        catch (NoSuchPaddingException e) {

            e.printStackTrace();
        }
        catch (BadPaddingException e) {

            e.printStackTrace();
        }
        catch (IllegalBlockSizeException e) {

            e.printStackTrace();
        }
        catch (InvalidKeyException e) {

            e.printStackTrace();
        }

        return new String(DataSecret.encode(result));
    }

    //解密
    public static String decrypt(String encrypted, String key){

        byte[] content = DataSecret.decode(encrypted);
        byte[] decoded = DataSecret.decode(key);

        byte[] result = new byte[]{0};

        try {

            RSAPrivateCrtKey priKey = (RSAPrivateCrtKey)KeyFactory.getInstance("RSA")
                    .generatePrivate(new PKCS8EncodedKeySpec(decoded));
            Cipher cipher = Cipher.getInstance(RSA_ALGORITHM);
            cipher.init(Cipher.DECRYPT_MODE, priKey);
            result = cipher.doFinal(content);
        }
        catch (InvalidKeySpecException e){

            e.printStackTrace();
        }
        catch (NoSuchAlgorithmException e) {

            e.printStackTrace();
        }
        catch (NoSuchPaddingException e) {

            e.printStackTrace();
        }
        catch (InvalidKeyException e) {

            e.printStackTrace();
        }
        catch (BadPaddingException e) {

            e.printStackTrace();
        }
        catch (IllegalBlockSizeException e) {

            e.printStackTrace();
        }

        return new String(result);
    }
}

调用代码：

    private static final String PUB_KEY = "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCjuN97tkBc0QcKGU9oXydaQN7q" +
            "wZnThxTOmdIc8O1yuA9FrDZpZ3Sz908vTqM/YPZkOUaYrGwsBO7FeQovoX7nQPKu" +
            "YQpRDqt7OKzhwPavyynH0Jz38PDyCBw45zwl4Ux8BtsggTrGVxAqNjO4KkuyL1QS" +
            "8amn4Fzl1CBre8Y0gQIDAQAB";

    private static final String PRI_KEY = "MIICdAIBADANBgkqhkiG9w0BAQEFAASCAl4wggJaAgEAAoGBAKO433u2QFzRBwoZ" +
            "T2hfJ1pA3urBmdOHFM6Z0hzw7XK4D0WsNmlndLP3Ty9Ooz9g9mQ5RpisbCwE7sV5" +
            "Ci+hfudA8q5hClEOq3s4rOHA9q/LKcfQnPfw8PIIHDjnPCXhTHwG2yCBOsZXECo2" +
            "M7gqS7IvVBLxqafgXOXUIGt7xjSBAgMBAAECgYAgp0uzcdsOaAY+ZmPnDitcHdoX" +
            "+jsC7EsjFZzJduf03G73V2yWwzKMfkPFzKpUhrM9tAq3gpQkh2tT6Vs1usEDbrDd" +
            "e08Cc3D5YWK7HuTfO3kkJTSNOK0JfuT1UQaTjCmDQWWjPmYbu6UN0UDv4Mo26dgl" +
            "cp9h0wlaPsSFN3O97QJBANgj+4i7ABAdbTuUfq6Tcr38E7wYSFTUeL5jTd4sO636" +
            "+KJ6zx4uTXAmxnt9OdIY1ihLRqDh8VbiorqOelGf6iMCQQDB6jZver3mTMe6ntSY" +
            "hx3JWOCDM3ULkPvOWGrAcRsNKjyIuo37taXa7fuqmVQQq9MJYikJfilMhkgwkV/X" +
            "ihcLAkBsOvBskj9A0ottJzmcT4dIbR6wtHQbzl078NwAIaQsxZyVN+vY0BTE0RXY" +
            "pmc6tmcevDr8uscv28Liqg/EKdCDAkAjL9C44djblUsYvgFtu/bXtlzm8ctnUeOf" +
            "ScP1L5DtDqD1XoStDAUQeOaVykTK0aL1rO4tXss3q5Yl2fs+LTyJAj8f7N5kzw08" +
            "9S5OWCHoEm5UOeAvjFh//cjXi6lyqetBW3w17muZ2OumUAbKJXksyzmT6/QRpkX3" +
            "S0w/tqdJXLs=";

    public static void main(String[] args) throws UnsupportedEncodingException {

        String content = "123456";
        String encrypted = RSA.encrypt(content, PUB_KEY);
        System.out.println(encrypted);
        System.out.println(RSA.decrypt(encrypted, PRI_KEY));
        ......
        ......
   }

运行截图如下：