准备工作
了解非对称加密算法 - RSA
公私钥对的概念
需要用到的jar包
Base64编码
为了解决ASCII中一些字符在IDEA中不可打印的问题，使用Base64编码
1、用于处理 密钥字符串
比如公钥：
MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCLhv3lCBJBUfg2cx4WPhmcK1/MiDJ6lwFlBp7Mngtpy+blrwu1mniRiv9Vu7a8u9zsBU0LM9UDXNKsB/ClEsYE1wwu5zcX5jHiQ0Nj2N8fIuo/J53hNetT3fGbN80T81Jf5DA0KV0J3pi7on9lOEZrOyFFZvb2SxapMWyWPGUdHwIDAQAB
其实代表的是一个数字
2、用于处理信息中的中文字符
代码
package RSA;
import org.apache.commons.codec.binary.Base64;
import javax.crypto.Cipher;
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.security.*;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
/**
* @author WuYongheng
* @date 2022/11/21
* @description
*/
public class RsaUtils {
public static void main(String[] args) throws Exception {
System.out.println();
// 生成公私钥对
RsaKeyPair keyPair = generateKeyPair();
System.out.println("公钥：" + keyPair.getPublicKey());
System.out.println("私钥：" + keyPair.getPrivateKey());
System.out.println();
test1(keyPair);
System.out.println("\n");
// test2(keyPair);
// System.out.println("\n");
}
/**
* 静态的，跑程序时会优先加载，去调用ReadData()方法
* 使用 final 关键字，保证读取到的数据不可更改
*/
private static final String SRC;
static {
try {
SRC = ReadData();
} catch (IOException e) {
throw new RuntimeException(e);
}
}
/**
* 使用缓存流读取 aaa.txt 文件中的内容
*
* @return 文件内容
* @throws IOException
*/
public static String ReadData() throws IOException {
String fileName = "D:\\code\\aaa.txt";
final StringBuilder myData = new StringBuilder();
try (BufferedReader br = new BufferedReader(new FileReader(fileName))) {
String line;
while ((line = br.readLine()) != null) {
System.out.println("文件内容是: " + line);
myData.append(line);
}
}
return myData.toString();
}
/**
* 公钥加密私钥解密
*
* @param keyPair
* @throws Exception
*/
private static void test1(RsaKeyPair keyPair) throws Exception {
System.out.println("***************** 公钥加密私钥解密开始 *****************");
// 用公钥加密得到 text1
String text1 = encryptByPublicKey(keyPair.getPublicKey(), RsaUtils.SRC);
// 用私钥解密 text1 得到 text2
String text2 = decryptByPrivateKey(keyPair.getPrivateKey(), text1);
System.out.println("加密前：" + RsaUtils.SRC);
System.out.println("加密后：" + text1);
System.out.println("解密后：" + text2);
if (RsaUtils.SRC.equals(text2)) {
System.out.println("解密字符串和原始字符串一致，解密成功");
} else {
System.out.println("解密字符串和原始字符串不一致，解密失败");
}
System.out.println("***************** 公钥加密私钥解密结束 *****************");
}
/**
* 私钥加密公钥解密
* 过程与 test1类似
*
* @param keyPair
* @throws Exception
*/
private static void test2(RsaKeyPair keyPair) throws Exception {
System.out.println("***************** 私钥加密公钥解密开始 *****************");
String text1 = encryptByPrivateKey(keyPair.getPrivateKey(), RsaUtils.SRC);
String text2 = decryptByPublicKey(keyPair.getPublicKey(), text1);
System.out.println("加密前：" + RsaUtils.SRC);
System.out.println("加密后：" + text1);
System.out.println("解密后：" + text2);
if (RsaUtils.SRC.equals(text2)) {
System.out.println("解密字符串和原始字符串一致，解密成功");
} else {
System.out.println("解密字符串和原始字符串不一致，解密失败");
}
System.out.println("***************** 私钥加密公钥解密结束 *****************");
}
/**
* 公钥加密方法
*
* @param publicKeyText 公钥
* @param text 将要加密的信息
* @return Base64编码的字符串
* @throws Exception
*/
public static String encryptByPublicKey(String publicKeyText, String text) throws Exception {
// 返回按照 X.509 标准进行编码的密钥的字节
// x509EncodedKeySpec2 是一种规范、规格
X509EncodedKeySpec x509EncodedKeySpec2 = new X509EncodedKeySpec(Base64.decodeBase64(publicKeyText));
KeyFactory keyFactory = KeyFactory.getInstance("RSA");
// 让密钥工厂按照指定的 规范 生成公钥
PublicKey publicKey = keyFactory.generatePublic(x509EncodedKeySpec2);
Cipher cipher = Cipher.getInstance("RSA");
// 对加密初始化，使用加密模式，公钥加密
// Cipher.ENCRYPT_MODE 可以用 1 代替
cipher.init(Cipher.ENCRYPT_MODE, publicKey);
byte[] result = cipher.doFinal(text.getBytes());
// 返回 Base64编码的字符串
return Base64.encodeBase64String(result);
}
/**
* 公钥解密方法
* 过程与encryptByPublicKey()方法类似
*
* @param publicKeyText 公钥
* @param text 待解密的信息
* @return 字符串
* @throws Exception
*/
public static String decryptByPublicKey(String publicKeyText, String text) throws Exception {
X509EncodedKeySpec x509EncodedKeySpec = new X509EncodedKeySpec(Base64.decodeBase64(publicKeyText));
KeyFactory keyFactory = KeyFactory.getInstance("RSA");
PublicKey publicKey = keyFactory.generatePublic(x509EncodedKeySpec);
Cipher cipher = Cipher.getInstance("RSA");
cipher.init(Cipher.DECRYPT_MODE, publicKey);
byte[] result = cipher.doFinal(Base64.decodeBase64(text));
return new String(result);
}
/**
* 私钥加密方法
* 过程与encryptByPublicKey()方法类似
*
* @param privateKeyText 私钥
* @param text 将要加密的信息
* @return Base64编码的字符串
* @throws Exception
*/
public static String encryptByPrivateKey(String privateKeyText, String text) throws Exception {
PKCS8EncodedKeySpec pkcs8EncodedKeySpec = new PKCS8EncodedKeySpec(Base64.decodeBase64(privateKeyText));
KeyFactory keyFactory = KeyFactory.getInstance("RSA");
PrivateKey privateKey = keyFactory.generatePrivate(pkcs8EncodedKeySpec);
Cipher cipher = Cipher.getInstance("RSA");
cipher.init(Cipher.ENCRYPT_MODE, privateKey);
byte[] result = cipher.doFinal(text.getBytes());
return Base64.encodeBase64String(result);
}
/**
* 私钥解密方法
* 过程与encryptByPublicKey()方法类似
*
* @param privateKeyText 私钥
* @param text 待解密的信息
* @return 字符串
* @throws Exception
*/
public static String decryptByPrivateKey(String privateKeyText, String text) throws Exception {
PKCS8EncodedKeySpec pkcs8EncodedKeySpec5 = new PKCS8EncodedKeySpec(Base64.decodeBase64(privateKeyText));
KeyFactory keyFactory = KeyFactory.getInstance("RSA");
PrivateKey privateKey = keyFactory.generatePrivate(pkcs8EncodedKeySpec5);
Cipher cipher = Cipher.getInstance("RSA");
cipher.init(Cipher.DECRYPT_MODE, privateKey);
byte[] result = cipher.doFinal(Base64.decodeBase64(text));
return new String(result);
}
/**
* 创建RSA公私钥对
*
* @return new RsaKeyPair(publicKeyString, privateKeyString)
* @throws NoSuchAlgorithmException
*/
public static RsaKeyPair generateKeyPair() throws NoSuchAlgorithmException {
// 创建公私钥对，指定算法 - RSA
KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA");
// 设置密钥大小 1024 bits， >=512
keyPairGenerator.initialize(1024);
// 创建KeyPair对象，用于接收公私钥对
KeyPair keyPair = keyPairGenerator.generateKeyPair();
// 生成随机的公私钥对
RSAPublicKey rsaPublicKey = (RSAPublicKey) keyPair.getPublic();
RSAPrivateKey rsaPrivateKey = (RSAPrivateKey) keyPair.getPrivate();
// 把密钥转换成 Base64编码的字符串
String publicKeyString = Base64.encodeBase64String(rsaPublicKey.getEncoded());
String privateKeyString = Base64.encodeBase64String(rsaPrivateKey.getEncoded());
return new RsaKeyPair(publicKeyString, privateKeyString);
}
/**
* RSA密钥对 对象
*/
public static class RsaKeyPair {
private final String publicKey;
private final String privateKey;
// 也可以将密钥写死
// private final String publicKey = "MFwwDQYJKoZIhvcNAQEBBQADSwAwSAJBAKYZdPEB9UtcTUCn/stBfgi3lu0CuUkQqwKy1tr9vEoeTe5KZqTJ4Fm3GxFChEgdPDUbglUhx0xIhBWu7yEUKy8CAwEAAQ==";
// private final String privateKey = "MIIBVQIBADANBgkqhkiG9w0BAQEFAASCAT8wggE7AgEAAkEAphl08QH1S1xNQKf+y0F+CLeW7QK5SRCrArLW2v28Sh5N7kpmpMngWbcbEUKESB08NRuCVSHHTEiEFa7vIRQrLwIDAQABAkEAmX+LH7L0kklhpy/ZetMyezHWy3+p5Yj+0QafIlA88qyivvHX2lsAMmHcr5HIVxfWDIZCStU+8sDEfLoVQ6H3uQIhAN0blNwWPBRJ+mFOURsfkPYe5k66ncOTqfKirHovqK3dAiEAwE+fh1F3xuyZWt3YUyDlhf29zl6rYmyO5e3zImxWCnsCIE0CkERfkilW4tgFWQZjZi/y7zA4mz5FLgoOUph0BQIZAiEAo8Ao2pRoJR45xsG3/bC5P8q74AmEbZ56XxaqPNl6uhkCIFiPu1Yc+oFzH0Z5hmxKUlnWqeU/unuZNxcZhbtGY2bd";
public RsaKeyPair(String publicKey, String privateKey) {
this.publicKey = publicKey;
this.privateKey = privateKey;
// publicKey = this.publicKey;
// privateKey = this.privateKey;
}
public String getPublicKey() {
return publicKey;
}
public String getPrivateKey() {
return privateKey;
}
}
}
验证
中文，英文字母，数字，特殊符号
