2024年Java最全Java使用RSA加密解密签名及校验，一招彻底帮你搞定HashMap源码

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由于篇幅限制，小编在此截出几张知识讲解的图解

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/**

• 从字符串中加载公钥

• @param publicKeyStr

•        公钥数据字符串 

• @throws Exception

•         加载公钥时产生的异常 

*/

public static RSAPublicKey loadPublicKeyByStr(String publicKeyStr)

throws Exception {

try {

byte[] buffer = Base64.decode(publicKeyStr);

KeyFactory keyFactory = KeyFactory.getInstance(“RSA”);

X509EncodedKeySpec keySpec = new X509EncodedKeySpec(buffer);

return (RSAPublicKey) keyFactory.generatePublic(keySpec);

} catch (NoSuchAlgorithmException e) {

throw new Exception(“无此算法”);

} catch (InvalidKeySpecException e) {

throw new Exception(“公钥非法”);

} catch (NullPointerException e) {

throw new Exception(“公钥数据为空”);

}

}

/**

• 从文件中加载私钥

• @param keyFileName

•        私钥文件名 

• @return 是否成功

• @throws Exception

*/

public static String loadPrivateKeyByFile(String path) throws Exception {

try {

BufferedReader br = new BufferedReader(new FileReader(path

• “/privateKey.keystore”));

String readLine = null;

StringBuilder sb = new StringBuilder();

while ((readLine = br.readLine()) != null) {

sb.append(readLine);

}

br.close();

return sb.toString();

} catch (IOException e) {

throw new Exception(“私钥数据读取错误”);

} catch (NullPointerException e) {

throw new Exception(“私钥输入流为空”);

}

}

public static RSAPrivateKey loadPrivateKeyByStr(String privateKeyStr)

throws Exception {

try {

byte[] buffer = Base64.decode(privateKeyStr);

PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(buffer);

KeyFactory keyFactory = KeyFactory.getInstance(“RSA”);

return (RSAPrivateKey) keyFactory.generatePrivate(keySpec);

} catch (NoSuchAlgorithmException e) {

throw new Exception(“无此算法”);

} catch (InvalidKeySpecException e) {

throw new Exception(“私钥非法”);

} catch (NullPointerException e) {

throw new Exception(“私钥数据为空”);

}

}

/**

• 公钥加密过程

• @param publicKey

•        公钥 

• @param plainTextData

•        明文数据 

• @return

• @throws Exception

•         加密过程中的异常信息 

*/

public static byte[] encrypt(RSAPublicKey publicKey, byte[] plainTextData)

throws Exception {

if (publicKey == null) {

throw new Exception(“加密公钥为空, 请设置”);

}

Cipher cipher = null;

try {

// 使用默认RSA

cipher = Cipher.getInstance(“RSA”);

// cipher= Cipher.getInstance(“RSA”, new BouncyCastleProvider());

cipher.init(Cipher.ENCRYPT_MODE, publicKey);

byte[] output = cipher.doFinal(plainTextData);

return output;

} catch (NoSuchAlgorithmException e) {

throw new Exception(“无此加密算法”);

} catch (NoSuchPaddingException e) {

e.printStackTrace();

return null;

} catch (InvalidKeyException e) {

throw new Exception(“加密公钥非法,请检查”);

} catch (IllegalBlockSizeException e) {

throw new Exception(“明文长度非法”);

} catch (BadPaddingException e) {

throw new Exception(“明文数据已损坏”);

}

}

/**

• 私钥加密过程

• @param privateKey

•        私钥 

• @param plainTextData

•        明文数据 

• @return

• @throws Exception

•         加密过程中的异常信息 

*/

public static byte[] encrypt(RSAPrivateKey privateKey, byte[] plainTextData)

throws Exception {

if (privateKey == null) {

throw new Exception(“加密私钥为空, 请设置”);

}

Cipher cipher = null;

try {

// 使用默认RSA

cipher = Cipher.getInstance(“RSA”);

cipher.init(Cipher.ENCRYPT_MODE, privateKey);

byte[] output = cipher.doFinal(plainTextData);

return output;

} catch (NoSuchAlgorithmException e) {

throw new Exception(“无此加密算法”);

} catch (NoSuchPaddingException e) {

e.printStackTrace();

return null;

} catch (InvalidKeyException e) {

throw new Exception(“加密私钥非法,请检查”);

} catch (IllegalBlockSizeException e) {

throw new Exception(“明文长度非法”);

} catch (BadPaddingException e) {

throw new Exception(“明文数据已损坏”);

}

}

/**

• 私钥解密过程

• @param privateKey

•        私钥 

• @param cipherData

•        密文数据 

• @return 明文

• @throws Exception

•         解密过程中的异常信息 

*/

public static byte[] decrypt(RSAPrivateKey privateKey, byte[] cipherData)

throws Exception {

if (privateKey == null) {

throw new Exception(“解密私钥为空, 请设置”);

}

Cipher cipher = null;

try {

// 使用默认RSA

cipher = Cipher.getInstance(“RSA”);

// cipher= Cipher.getInstance(“RSA”, new BouncyCastleProvider());

cipher.init(Cipher.DECRYPT_MODE, privateKey);

byte[] output = cipher.doFinal(cipherData);

return output;

} catch (NoSuchAlgorithmException e) {

throw new Exception(“无此解密算法”);

} catch (NoSuchPaddingException e) {

e.printStackTrace();

return null;

} catch (InvalidKeyException e) {

throw new Exception(“解密私钥非法,请检查”);

} catch (IllegalBlockSizeException e) {

throw new Exception(“密文长度非法”);

} catch (BadPaddingException e) {

throw new Exception(“密文数据已损坏”);

}

}

/**

• 公钥解密过程

• @param publicKey

•        公钥 

• @param cipherData

•        密文数据 

• @return 明文

• @throws Exception

•         解密过程中的异常信息 

*/

public static byte[] decrypt(RSAPublicKey publicKey, byte[] cipherData)

throws Exception {

if (publicKey == null) {

throw new Exception(“解密公钥为空, 请设置”);

}

Cipher cipher = null;

try {

// 使用默认RSA

cipher = Cipher.getInstance(“RSA”);

// cipher= Cipher.getInstance(“RSA”, new BouncyCastleProvider());

cipher.init(Cipher.DECRYPT_MODE, publicKey);

byte[] output = cipher.doFinal(cipherData);

return output;

} catch (NoSuchAlgorithmException e) {

throw new Exception(“无此解密算法”);

} catch (NoSuchPaddingException e) {

e.printStackTrace();

return null;

} catch (InvalidKeyException e) {

throw new Exception(“解密公钥非法,请检查”);

} catch (IllegalBlockSizeException e) {

throw new Exception(“密文长度非法”);

} catch (BadPaddingException e) {

throw new Exception(“密文数据已损坏”);

}

}

/**

• 字节数据转十六进制字符串

• @param data

•        输入数据 

• @return 十六进制内容

*/

public static String byteArrayToString(byte[] data) {

StringBuilder stringBuilder = new StringBuilder();

for (int i = 0; i < data.length; i++) {

// 取出字节的高四位 作为索引得到相应的十六进制标识符 注意无符号右移

stringBuilder.append(HEX_CHAR[(data[i] & 0xf0) >>> 4]);

// 取出字节的低四位 作为索引得到相应的十六进制标识符

stringBuilder.append(HEX_CHAR[(data[i] & 0x0f)]);

if (i < data.length - 1) {

stringBuilder.append(’ ');

}

}

return stringBuilder.toString();

}

}

签名及校验类：

package com.ihep;

import java.security.KeyFactory;

import java.security.PrivateKey;

import java.security.PublicKey;

import java.security.spec.PKCS8EncodedKeySpec;

import java.security.spec.X509EncodedKeySpec;

/**

• RSA签名验签类

*/

public class RSASignature{

/**

• 签名算法

*/

public static final String SIGN_ALGORITHMS = “SHA1WithRSA”;

/**

• RSA签名

• @param content 待签名数据

• @param privateKey 商户私钥

• @param encode 字符集编码

• @return 签名值

*/

public static String sign(String content, String privateKey, String encode)

{

try

{

PKCS8EncodedKeySpec priPKCS8 = new PKCS8EncodedKeySpec( Base64.decode(privateKey) );

KeyFactory keyf = KeyFactory.getInstance(“RSA”);

PrivateKey priKey = keyf.generatePrivate(priPKCS8);

java.security.Signature signature = java.security.Signature.getInstance(SIGN_ALGORITHMS);

signature.initSign(priKey);

signature.update( content.getBytes(encode));

byte[] signed = signature.sign();

return Base64.encode(signed);

}

catch (Exception e)

{

e.printStackTrace();

}

return null;

}

public static String sign(String content, String privateKey)

{

try

{

PKCS8EncodedKeySpec priPKCS8 = new PKCS8EncodedKeySpec( Base64.decode(privateKey) );

KeyFactory keyf = KeyFactory.getInstance(“RSA”);

PrivateKey priKey = keyf.generatePrivate(priPKCS8);

java.security.Signature signature = java.security.Signature.getInstance(SIGN_ALGORITHMS);

signature.initSign(priKey);

signature.update( content.getBytes());

byte[] signed = signature.sign();

return Base64.encode(signed);

}

catch (Exception e)

{

e.printStackTrace();

}

return null;

}

/**

• RSA验签名检查

• @param content 待签名数据

• @param sign 签名值

• @param publicKey 分配给开发商公钥

• @param encode 字符集编码

• @return 布尔值

*/

public static boolean doCheck(String content, String sign, String publicKey,String encode)

{

try

{

KeyFactory keyFactory = KeyFactory.getInstance(“RSA”);

byte[] encodedKey = Base64.decode(publicKey);

PublicKey pubKey = keyFactory.generatePublic(new X509EncodedKeySpec(encodedKey));

java.security.Signature signature = java.security.Signature

.getInstance(SIGN_ALGORITHMS);

signature.initVerify(pubKey);

signature.update( content.getBytes(encode) );

boolean bverify = signature.verify( Base64.decode(sign) );

return bverify;

}

catch (Exception e)

{

e.printStackTrace();

}

return false;

}

public static boolean doCheck(String content, String sign, String publicKey)

{

try

{

KeyFactory keyFactory = KeyFactory.getInstance(“RSA”);

byte[] encodedKey = Base64.decode(publicKey);

PublicKey pubKey = keyFactory.generatePublic(new X509EncodedKeySpec(encodedKey));

java.security.Signature signature = java.security.Signature

.getInstance(SIGN_ALGORITHMS);

signature.initVerify(pubKey);

signature.update( content.getBytes() );

boolean bverify = signature.verify( Base64.decode(sign) );

return bverify;

}

catch (Exception e)

{

e.printStackTrace();

}

return false;

}

}

再来一个Base64的类，当然你也可以用commons-codec-1.9.jar

package com.ihep;

public final class Base64 {

static private final int BASELENGTH = 128;

static private final int LOOKUPLENGTH = 64;

static private final int TWENTYFOURBITGROUP = 24;

static private final int EIGHTBIT = 8;

static private final int SIXTEENBIT = 16;

static private final int FOURBYTE = 4;

static private final int SIGN = -128;

static private final char PAD = ‘=’;

static private final boolean fDebug = false;

static final private byte[] base64Alphabet = new byte[BASELENGTH];

static final private char[] lookUpBase64Alphabet = new char[LOOKUPLENGTH];

static {

for (int i = 0; i < BASELENGTH; ++i) {

base64Alphabet[i] = -1;

}

for (int i = ‘Z’; i >= ‘A’; i–) {

base64Alphabet[i] = (byte) (i - ‘A’);

}

for (int i = ‘z’; i >= ‘a’; i–) {

base64Alphabet[i] = (byte) (i - ‘a’ + 26);

}

for (int i = ‘9’; i >= ‘0’; i–) {

base64Alphabet[i] = (byte) (i - ‘0’ + 52);

}

base64Alphabet[‘+’] = 62;

base64Alphabet[‘/’] = 63;

for (int i = 0; i <= 25; i++) {

lookUpBase64Alphabet[i] = (char) (‘A’ + i);

}

for (int i = 26, j = 0; i <= 51; i++, j++) {

lookUpBase64Alphabet[i] = (char) (‘a’ + j);

}

for (int i = 52, j = 0; i <= 61; i++, j++) {

lookUpBase64Alphabet[i] = (char) (‘0’ + j);

}

lookUpBase64Alphabet[62] = (char) ‘+’;

lookUpBase64Alphabet[63] = (char) ‘/’;

}

private static boolean isWhiteSpace(char octect) {

return (octect == 0x20 || octect == 0xd || octect == 0xa || octect == 0x9);

}

private static boolean isPad(char octect) {

return (octect == PAD);

}

private static boolean isData(char octect) {

return (octect < BASELENGTH && base64Alphabet[octect] != -1);

}

/**

• Encodes hex octects into Base64

• @param binaryData Array containing binaryData

• @return Encoded Base64 array

*/

public static String encode(byte[] binaryData) {

if (binaryData == null) {

return null;

}

int lengthDataBits = binaryData.length * EIGHTBIT;

if (lengthDataBits == 0) {

return “”;

}

int fewerThan24bits = lengthDataBits % TWENTYFOURBITGROUP;

int numberTriplets = lengthDataBits / TWENTYFOURBITGROUP;

int numberQuartet = fewerThan24bits != 0 ? numberTriplets + 1 : numberTriplets;

char encodedData[] = null;

encodedData = new char[numberQuartet * 4];

byte k = 0, l = 0, b1 = 0, b2 = 0, b3 = 0;

int encodedIndex = 0;

int dataIndex = 0;

if (fDebug) {

System.out.println("number of triplets = " + numberTriplets);

}

for (int i = 0; i < numberTriplets; i++) {

b1 = binaryData[dataIndex++];

b2 = binaryData[dataIndex++];

b3 = binaryData[dataIndex++];

if (fDebug) {

System.out.println("b1= " + b1 + ", b2= " + b2 + ", b3= " + b3);

}

l = (byte) (b2 & 0x0f);

k = (byte) (b1 & 0x03);

byte val1 = ((b1 & SIGN) == 0) ? (byte) (b1 >> 2) : (byte) ((b1) >> 2 ^ 0xc0);

byte val2 = ((b2 & SIGN) == 0) ? (byte) (b2 >> 4) : (byte) ((b2) >> 4 ^ 0xf0);

byte val3 = ((b3 & SIGN) == 0) ? (byte) (b3 >> 6) : (byte) ((b3) >> 6 ^ 0xfc);

笔者福利

以下是小编自己针对马上即将到来的金九银十准备的一套“面试宝典”，不管是技术还是HR的问题都有针对性的回答。

有了这个，面试踩雷？不存在的！

回馈粉丝，诚意满满！！！

本文已被CODING开源项目：【一线大厂Java面试题解析+核心总结学习笔记+最新讲解视频+实战项目源码】收录

需要这份系统化的资料的朋友，可以点击这里获取

}

for (int i = 0; i < numberTriplets; i++) {

b1 = binaryData[dataIndex++];

b2 = binaryData[dataIndex++];

b3 = binaryData[dataIndex++];

if (fDebug) {

System.out.println("b1= " + b1 + ", b2= " + b2 + ", b3= " + b3);

}

l = (byte) (b2 & 0x0f);

k = (byte) (b1 & 0x03);

byte val1 = ((b1 & SIGN) == 0) ? (byte) (b1 >> 2) : (byte) ((b1) >> 2 ^ 0xc0);

byte val2 = ((b2 & SIGN) == 0) ? (byte) (b2 >> 4) : (byte) ((b2) >> 4 ^ 0xf0);

byte val3 = ((b3 & SIGN) == 0) ? (byte) (b3 >> 6) : (byte) ((b3) >> 6 ^ 0xfc);

笔者福利

以下是小编自己针对马上即将到来的金九银十准备的一套“面试宝典”，不管是技术还是HR的问题都有针对性的回答。

有了这个，面试踩雷？不存在的！

回馈粉丝，诚意满满！！！

[外链图片转存中…(img-0iLIDuep-1714856977064)]
[外链图片转存中…(img-7Q2QkTJG-1714856977064)]
[外链图片转存中…(img-geHBVrGp-1714856977065)]
[外链图片转存中…(img-GlJXW5Mr-1714856977065)]

本文已被CODING开源项目：【一线大厂Java面试题解析+核心总结学习笔记+最新讲解视频+实战项目源码】收录

需要这份系统化的资料的朋友，可以点击这里获取