大家好，又见面了，我是你们的朋友全栈君。
RSA加密密钥是非对称的，一般是成对出现分为公钥和私钥，所以也叫非对称加密，可以公钥加密，私钥解密，也可以私钥加密，公钥解密。
一般用于数据加密。
初始化密钥，可生成一对RSA密钥：
代码语言：javascript复制KeyPairGenerator keyPairGenerator= KeyPairGenerator.getInstance("RSA"); ---设置加密算法
keyPairGenerator.initialize(2048); ---设置密钥的位数
KeyPair keyPair=keyPairGenerator.generateKeyPair();
RSAPublicKey rsaPublicKey=(RSAPublicKey)keyPair.getPublic(); ----公钥
RSAPrivateKey rsaPrivateKey=(RSAPrivateKey)keyPair.getPrivate(); ----私钥
System.out.println("publickey:" Base64.encodeBase64String(rsaPublicKey.getEncoded())); ---输出的是字符串型公钥
System.out.println("privatekey:" Base64.encodeBase64String(rsaPrivateKey.getEncoded())); ---输出的是字符串型私钥需要注意的是，需要使用Base64 类来对密钥进行相应的转换，需要导入jar包 commons-codec-1.8.jar
有两个常用的方法： encodeBase64String（byte数组）；用于将byte数组类型的密钥转换成字符串型密钥 decodeBase64（字符串）； 用于将字符串型密钥转换成byte数组型密钥
使用公钥加密：
代码语言：javascript复制//获取公钥
X509EncodedKeySpec x509EncodedKeySpec=new X509EncodedKeySpec(pubKey); ---使用公钥时用的一个关键类，
//密钥工厂初始化
KeyFactory keyFactory=KeyFactory.getInstance("RSA"); //生成公钥
PublicKey publicKey=keyFactory
.generatePublic(x509EncodedKeySpec); //数据加密
Cipher cipher=Cipher.getInstance("RSA");
cipher.init(Cipher.ENCRYPT_MODE, publicKey); ----设置是模式，即加密还是解密，此处是加密 ENCRYPT_MODE
byte[] result=cipher.doFinal(data);
return result;返回的result就是加密后的byte型密文，注意转成字符串是需要用Base64的方法
使用私钥解密：
代码语言：javascript复制//获取私钥
PKCS8EncodedKeySpec pkcs8EncodedKeySpec=new PKCS8EncodedKeySpec(privKey); --使用私钥时用的一个关键类
//密钥工厂初始化
KeyFactory keyFactory=KeyFactory.getInstance("RSA"); //生成私钥
PrivateKey privateKey=keyFactory
.generatePrivate(pkcs8EncodedKeySpec); //数据解密
Cipher cipher=Cipher.getInstance("RSA");
cipher.init(Cipher.DECRYPT_MODE, privateKey); -------设置是模式，即加密还是解密，此处是解密DECRYPT_MODE
byte[] clearText=cipher.doFinal(cipherText);
return clearText; 返回的就是byte类型的解密后的明文，注意转成字符串是不需要用Base64的方法，直接new 一个String对象就行newString（clearText）
源码：
代码语言：javascript复制package org.me.demo1;
import java.security.InvalidKeyException;
import java.security.KeyFactory;
import java.security.NoSuchAlgorithmException;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.Arrays;
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import org.apache.commons.codec.binary.Base64;
/** * * @author zhouluping * RSA公钥加密和私钥解密 * 需要导一个jar包 commons-codec-1.8.jar， Base64类 用于将密文转换成byte数组 */
public class RsaDemo2 {
//公钥加密
public static byte[] rsaEncrypt(byte[] data,byte[] pubKey){
try {
//获取公钥
X509EncodedKeySpec x509EncodedKeySpec=new X509EncodedKeySpec(pubKey);
//密钥工厂初始化
KeyFactory keyFactory=KeyFactory.getInstance("RSA");
//生成公钥
PublicKey publicKey=keyFactory.generatePublic(x509EncodedKeySpec);
//数据加密
Cipher cipher=Cipher.getInstance("RSA");
cipher.init(Cipher.ENCRYPT_MODE, publicKey);
byte[] result=cipher.doFinal(data);
return result;
} catch (NoSuchAlgorithmException e) {
System.out.println("NoSuchAlgorithmException!");
} catch (InvalidKeySpecException e) {
System.out.println("InvalidKeySpecException!");
} catch (NoSuchPaddingException e) {
System.out.println("NoSuchPaddingException!");
} catch (InvalidKeyException e) {
System.out.println("InvalidKeyException!");
} catch (IllegalBlockSizeException e) {
System.out.println("IllegalBlockSizeException!");
} catch (BadPaddingException e) {
System.out.println("IllegalBlockSizeException!");
}
return null;
}
//私钥解密
public static byte[] rsaDecrypt(byte[] cipherText,byte[] privKey){
try {
//获取私钥
PKCS8EncodedKeySpec pkcs8EncodedKeySpec=new PKCS8EncodedKeySpec(privKey);
//密钥工厂初始化
KeyFactory keyFactory=KeyFactory.getInstance("RSA");
//生成私钥
PrivateKey privateKey=keyFactory.generatePrivate(pkcs8EncodedKeySpec);
//数据解密
Cipher cipher=Cipher.getInstance("RSA");
cipher.init(Cipher.DECRYPT_MODE, privateKey);
byte[] clearText=cipher.doFinal(cipherText);
return clearText;
} catch (NoSuchAlgorithmException e) {
System.out.println("NoSuchAlgorithmException!");
} catch (InvalidKeySpecException e) {
System.out.println("InvalidKeySpecException!");
} catch (NoSuchPaddingException e) {
System.out.println("NoSuchPaddingException!");
} catch (InvalidKeyException e) {
System.out.println("InvalidKeyException!");
} catch (IllegalBlockSizeException e) {
System.out.println("IllegalBlockSizeException!");
} catch (BadPaddingException e) {
System.out.println("IllegalBlockSizeException!");
}
return null;
}
public static void main(String[] args) {
// String pubKey="MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAqUWHDpQcks/TcWTR5kFM2TXBUS9Gsm/qJ6ZTN9lGQlXIEQEaVwze8YpcgcVnQjbd5V ogejZlO2EbYygwdzHDYDK5foNy9xk3Tpf9RF1h6X0ilsGSmbt7IIJoTK76C35ep/r7EiVR LVNxF47OKVevIk6bvFca2Tg2Qfcc1wTZTHF2BD9EcnCt7a4pDYK1q0S 1pnald6yrCZIHtBuxZ5B5x099ArRHackQzf6FrxVuVud3Du98NlbJIVtm7L0l9sVmx4ItdGUA3YTSAzwd67l52ka5gVkLeGdpWTEiLLNJbBVXesqdLEdVub/q9Di23v3ftZC9vXWU/VOmLc5mDnwIDAQAB";
String pubKey="MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAp8CEgkk2 5fgSncArbujdZyBCrN8D5cpSHHAm/ItkA3DuGV3cYqDV83Xx5m173UETOkJvhhSi/uT4d lxqk4NBh0CYHfP6gElDHp syQ5dvrm6jxiwnc/3RBOfyusa4kDrknGncn w9iwruB7Wsng/YnA4G99BjXfI QCYzgUSJYQxetZg79805kIxu0/hfMqkQWCdwUV6B0bk2Cn5CLWhRk/MT1gTgVclVJHw1Bb83wWmYtHu0PWfUyUi nM3o8jzXKuwBK8aDqNZ2EXMZ5GTU1TXBYbdyZ17YhOU3kD/hdTYwzXdzr7wSv/f RZWaOPF5doqfOLP3VKRRH/IPy3wIDAQAB";
String clearText="today is third day!";
System.out.println("未加密明文：" clearText);
byte[] cipherText=rsaEncrypt(clearText.getBytes(),Base64.decodeBase64(pubKey));
System.out.println("密文：" Base64.encodeBase64String(cipherText));
String priKey="MIIEvwIBADANBgkqhkiG9w0BAQEFAASCBKkwggSlAgEAAoIBAQCnwISCSTb7l BKdwCtu6N1nIEKs3wPlylIccCb8i2QDcO4ZXdxioNXzdfHmbXvdQRM6Qm GFKL 5Ph36XGqTg0GHQJgd8/qASUMen6zJDl2 ubqPGLCdz/dEE5/K6xriQOuScadyf7D2LCu4HtayeD9icDgb30GNd8j5AJjOBRIlhDF61mDv3zTmQjG7T F8yqRBYJ3BRXoHRuTYKfkItaFGT8xPWBOBVyVUkfDUFvzfBaZi0e7Q9Z9TJSL6czejyPNcq7AErxoOo1nYRcxnkZNTVNcFht3JnXtiE5TeQP F1NjDNd3OvvBK/9/5FlZo48Xl2ip84s/dUpFEf8g/LfAgMBAAECggEBAKd7ttC9eH/JKs4t8ieC57hNASlF d829Ki3qa4JJSRmGbrI03Aw8uF/Sqil9teU5S5EnM2GSyQnkYY6XLDz0oFwyKmVWOedQLUVAJ6 DwzvfVR0YHSI7HTABT934JLVYnqwsTHjNa btObnftkj2tgNsvX1W0mSY9KhIxXl6TAWkOe9o1h3nWt6fLtnAFzxbi43REY0R7Il6onRIzJ1HHo6j/uW3RiridXPsNQ7YyXUj3qBAlwtmzHQDfoo4yKZMe/WpmfNKkG/lsaDipc3oJvJ2rGVfgPEJSTL0R3pFlypSpjS0jU4qOk9eFhJLDMn2qpcDbl8G DrXqvdYEt7TUECgYEA7AxwXUZPaORIK3JqWpC971i8y73NdQ 0UpDV9lV/AepJl4unKVycfugNhgjKxo5 hL13r6DMte3aO69yqJ4qUTlAe7SpctzrOXJXsLam Me/x9OWfAQH29 Ro04WYOO9H9o2U1l8PtMhHloFM5dTxSgXwOnYUkOvR4tKO1gK80CgYEAte5LX6/3NcU4VNY831dnJ5gOfrvjf9ywenvKI7/HobKLQWmR9mQ8cTjydVLswAlNREAM0RhUnIDR9ctFLR4 n45DzUeMMYBH/6it7Pgn7clnmMK Llf69GDT5CY08wkcakSeEOKxhJm9O/2HGXJuUmVYTTllUINgnpJSFlq 5VsCgYEAtrEt6lM3tMQyQ0YroGq0RmIUxU/ii76i/lMO6hgxH35CYYq1YtH UM/igNuPpJWI188C8uHao2gn8RQOWp4C62eCI0vXRzC/F8tFXo1LKynO3MA7IQrXP61IO4yjV0ymQP 3g7AOvUOSRlm8v5W0zDb3pHIsgvRLbv3DEBEgxOUCgYAsBwMOoRL XEAJp98LXaeFGXNIkEe6Bbpfqd19UUgKhZ7Vsaq1KgTGkbV7VxocTyP3xFhVscGoLjShexO m3ckPdWCtDHlONozsKqGknd3QCpl Zr0tC3zPguJRwXBWw8ZWIm4JGQ5Zss43V34dozkO8pmxeES3vhe56Id7tALyQKBgQDek9tvdRRieNpqsTNhaPIPXa5ZFZ6pmyNpn6WWUx/ZOTApprM6kD4yFPhdzBFaeLl U/C0Dmb1SKKWAPKJw6BEThv60db5oei7CE6zu2PAkJ83GAvJSFXrbDdK5y14CEXa Zd3it5duT03A8uKsTe8gpSIIvATd5hN8YnJDkWa/w==";
byte[] dectyptText=rsaDecrypt(cipherText, Base64.decodeBase64(priKey));
System.out.println("解密后的明文：" new String(dectyptText));
}
}发布者：全栈程序员栈长，转载请注明出处：https://javaforall.cn/138507.html原文链接：https://javaforall.cn
