package com.fzzy.api.utils;
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import lombok.extern.slf4j.Slf4j;
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import org.apache.commons.lang.ArrayUtils;
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import javax.crypto.Cipher;
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import java.io.ByteArrayOutputStream;
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import java.nio.charset.StandardCharsets;
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import java.security.*;
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import java.security.interfaces.RSAPrivateKey;
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import java.security.interfaces.RSAPublicKey;
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import java.security.spec.PKCS8EncodedKeySpec;
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import java.security.spec.X509EncodedKeySpec;
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import java.util.Arrays;
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import java.util.Base64;
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import java.util.HashMap;
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import java.util.Map;
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@Slf4j
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public class RSAUtils {
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public static final String KEY_ALGORITHM = "RSA";
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private static final String PUBLIC_KEY = "RSAPublicKey";
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private static final String PRIVATE_KEY = "RSAPrivateKey";
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private static final String CHARSET = "utf-8";
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private static final int KEYSIZE = 1024;// 密钥位数
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private static final int RESERVE_BYTES = 11;
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private static final String ECB_PADDING = "RSA/ECB/PKCS1Padding";
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// 2048 bits 的 RSA 密钥对，最大解密密文大小
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private static final int MAX_DECRYPT_BLOCK = KEYSIZE / 8;
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// 2048 bits 的 RSA 密钥对，最大加密明文大小
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private static final int MAX_ENCRYPT_BLOCK = MAX_DECRYPT_BLOCK - RESERVE_BYTES;
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public static void main(String[] args) throws Exception {
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Map<String, Object> map = initKey(1024);
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String privateKeyStr = getPrivateKeyStr(map);
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log.info("-----私钥={}", privateKeyStr);
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System.out.println(privateKeyStr.length());
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String publicKeyStr = getPublicKeyStr(map);
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log.info("-----公钥={}", publicKeyStr);
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}
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// 生成密钥对
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public static Map<String, Object> initKey(int keysize) throws Exception {
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KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance(KEY_ALGORITHM);
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// 设置密钥对的 bit 数，越大越安全
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keyPairGen.initialize(keysize);
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KeyPair keyPair = keyPairGen.generateKeyPair();
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// 获取公钥
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RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();
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// 获取私钥
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RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();
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Map<String, Object> keyMap = new HashMap<>(2);
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keyMap.put(PUBLIC_KEY, publicKey);
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keyMap.put(PRIVATE_KEY, privateKey);
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return keyMap;
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}
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// 获取公钥字符串
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public static String getPublicKeyStr(Map<String, Object> keyMap) {
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// 获得 map 中的公钥对象，转为 key 对象
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Key key = (Key) keyMap.get(PUBLIC_KEY);
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// 编码返回字符串
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return encryptBASE64(key.getEncoded());
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}
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// 获取私钥字符串
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public static String getPrivateKeyStr(Map<String, Object> keyMap) {
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// 获得 map 中的私钥对象，转为 key 对象
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Key key = (Key) keyMap.get(PRIVATE_KEY);
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// 编码返回字符串
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return encryptBASE64(key.getEncoded());
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}
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// 获取公钥
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public static PublicKey getPublicKey(String publicKeyString) throws Exception {
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byte[] publicKeyByte = Base64.getDecoder().decode(publicKeyString);
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X509EncodedKeySpec keySpec = new X509EncodedKeySpec(publicKeyByte);
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KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
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return keyFactory.generatePublic(keySpec);
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}
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// 获取私钥
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public static PrivateKey getPrivateKey(String privateKeyString) throws Exception {
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byte[] privateKeyByte = Base64.getDecoder().decode(privateKeyString);
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PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(privateKeyByte);
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KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
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return keyFactory.generatePrivate(keySpec);
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}
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/**
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* BASE64 编码返回加密字符串
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*
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* @param key 需要编码的字节数组
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* @return 编码后的字符串
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*/
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public static String encryptBASE64(byte[] key) {
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return new String(Base64.getEncoder().encode(key));
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}
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/**
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* BASE64 解码，返回字节数组
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*
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* @param key 待解码的字符串
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* @return 解码后的字节数组
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*/
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public static byte[] decryptBASE64(String key) {
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return Base64.getDecoder().decode(key);
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}
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/**
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* 公钥加密
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*
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* @param text 待加密的明文字符串
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* @param publicKeyStr 公钥
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* @return 加密后的密文
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*/
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public static String encrypt(String text, String publicKeyStr) {
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String result = "";
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try {
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log.info("明文字符串为:[{}]", text);
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// 加密
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Cipher cipher = Cipher.getInstance(KEY_ALGORITHM);
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cipher.init(Cipher.ENCRYPT_MODE, getPublicKey(publicKeyStr));
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byte[] textArray = text.getBytes();
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int textLength = textArray.length;
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log.info("加密字节数={}", textLength);
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// 最大加密字节数，超出最大字节数需要分组加密
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int MAX_ENCRYPT_BLOCK = 117;
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// 标识
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int offSet = 0;
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byte[] resultBytes = {};
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byte[] cache = {};
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while (textLength - offSet > 0) {
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if (textLength - offSet > MAX_ENCRYPT_BLOCK) {
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cache = cipher.doFinal(textArray, offSet, MAX_ENCRYPT_BLOCK);
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offSet += MAX_ENCRYPT_BLOCK;
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} else {
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cache = cipher.doFinal(textArray, offSet, textLength - offSet);
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offSet = textLength;
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}
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resultBytes = Arrays.copyOf(resultBytes, resultBytes.length + cache.length);
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System.arraycopy(cache, 0, resultBytes, resultBytes.length - cache.length, cache.length);
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}
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result = Base64.getEncoder().encodeToString(resultBytes);
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} catch (Exception e) {
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throw new RuntimeException("加密字符串[" + text + "]时遇到异常", e);
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}
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return result;
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}
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/**
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* 私钥解密
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*
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* @param secretText 待解密的密文字符串
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* @param privateKeyStr 私钥
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* @return 解密后的明文
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*/
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public static String decrypt(String secretText, String privateKeyStr) {
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try {
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// 生成私钥
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Cipher cipher = Cipher.getInstance(KEY_ALGORITHM);
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cipher.init(Cipher.DECRYPT_MODE, getPrivateKey(privateKeyStr));
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// 密文解码
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byte[] data = Base64.getDecoder().decode(secretText);
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// 返回UTF-8编码的解密信息
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int inputLen = data.length;
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ByteArrayOutputStream out = new ByteArrayOutputStream();
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int offSet = 0;
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byte[] cache;
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int i = 0;
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// 对数据分段解密
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while (inputLen - offSet > 0) {
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if (inputLen - offSet > MAX_DECRYPT_BLOCK) {
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cache = cipher.doFinal(data, offSet, MAX_DECRYPT_BLOCK);
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} else {
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cache = cipher.doFinal(data, offSet, inputLen - offSet);
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}
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out.write(cache, 0, cache.length);
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i++;
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offSet = i * MAX_DECRYPT_BLOCK;
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}
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out.close();
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return out.toString(CHARSET);
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} catch (Exception e) {
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throw new RuntimeException("解密字符串[" + secretText + "]时遇到异常", e);
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}
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}
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/**
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* 私钥加密
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*
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* @param text
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* @param privateInfoStr
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* @return
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*/
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public static String encryptData(String text, String privateInfoStr) {
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try {
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log.info("明文字符串为:[{}]", text);
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Cipher cipher = Cipher.getInstance(ECB_PADDING);
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cipher.init(Cipher.ENCRYPT_MODE, getPrivateKey(privateInfoStr));
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// URLEncoder编码解决中文乱码问题
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byte[] data = text.getBytes(StandardCharsets.UTF_8);
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byte[] enBytes = null;
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for (int i = 0; i < data.length; i += MAX_ENCRYPT_BLOCK) {
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// 注意要使用2的倍数，否则会出现加密后的内容再解密时为乱码
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byte[] doFinal = cipher.doFinal(ArrayUtils.subarray(data, i, i + MAX_ENCRYPT_BLOCK));
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enBytes = ArrayUtils.addAll(enBytes, doFinal);
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}
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return Base64.getEncoder().encodeToString(enBytes);
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} catch (Exception e) {
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throw new RuntimeException("加密字符串[" + text + "]时遇到异常", e);
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}
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}
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/**
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* 公钥解密
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*
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* @param secretText
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* @param publicInfoStr
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* @return
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*/
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public static String decryptData(String secretText, String publicInfoStr) {
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try {
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//解密
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Cipher cipher = Cipher.getInstance(ECB_PADDING);
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cipher.init(Cipher.DECRYPT_MODE, getPublicKey(publicInfoStr));
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// 密文解码
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byte[] data = Base64.getDecoder().decode(secretText);
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// 返回UTF-8编码的解密信息
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int inputLen = data.length;
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ByteArrayOutputStream out = new ByteArrayOutputStream();
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int offSet = 0;
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byte[] cache;
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int i = 0;
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// 对数据分段解密
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while (inputLen - offSet > 0) {
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if (inputLen - offSet > MAX_DECRYPT_BLOCK) {
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cache = cipher.doFinal(data, offSet, MAX_DECRYPT_BLOCK);
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} else {
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cache = cipher.doFinal(data, offSet, inputLen - offSet);
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}
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out.write(cache, 0, cache.length);
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i++;
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offSet = i * MAX_DECRYPT_BLOCK;
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}
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out.close();
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return out.toString(CHARSET);
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} catch (Exception e) {
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throw new RuntimeException("解密字符串[" + secretText + "]时遇到异常", e);
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}
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}
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}
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