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Java使用RSA的公钥加密，私钥解密；私钥加密，公钥解密

tech2025-12-31  2

Java使用RSA的公钥加密，私钥解密；私钥加密，公钥解密

import lombok.extern.slf4j.Slf4j; import org.apache.commons.codec.binary.Base64; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Component; import org.system.common.util.RedisUtil; import javax.crypto.Cipher; import java.security.*; import java.security.interfaces.RSAPrivateKey; import java.security.interfaces.RSAPublicKey; import java.security.spec.PKCS8EncodedKeySpec; import java.security.spec.X509EncodedKeySpec; import java.util.HashMap; import java.util.Map; @Slf4j public class RSAEncrypt { public static void main(String[] args) throws Exception { String point = "xxx"; // Map<String, String> keyMap = genKeyPair(point); //生成公钥和私钥 Map<String, String> keyMap = new HashMap<>();//genKeyPair(); keyMap.put("publicKey", "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDOUDwJVY1JMY4oSHM1+VKeYZ5T2LjQ4wvENnt0TlRoOYDrUen4Nm3GbVKiGTot76gu7xYL1X9PQvDnYLpUVu0mA2oLrXWZj2ByTW83Ehdc5Y9aLXtNzmm4e6PXtuEtXk2sqUZz+XtBBAUMAne4J9G9DAZVPLFxUUJyzVb9cnK6NQIDAQAB"); keyMap.put("privateKey", "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"); String publicKey = keyMap.get("publicKey"); String privateKey = keyMap.get("privateKey"); System.out.println(publicKey); System.out.println(privateKey); // //加密字符串 String message = "我是测试"; System.out.println("前端请求的原数据\n"+message); String messageEn = publicKeyEncrypt(message, publicKey,point); System.out.println("前端请求的加密:\n" + messageEn); String messageDe = privateKeyDecrypt(messageEn, privateKey,point); System.out.println("后端解密出来的数据:\n" + messageDe); System.out.println("====================="); //前端数据展示处理 // //私钥加密，公钥解密 String s = privateKeyEncrypt(messageDe, privateKey,point); System.out.println("后端返回的加密数据\n"+s); // s = "M3sQjI8vSpWzyuiyNakHaMRb0QgKSt9aHoAYj1G6cLenPJ235IqGwsipO/tU8WlObn35aUM0vXKCmeLO0E1Qip7FKoYB4OYhD74anwXZFwb7cTXBiazvP5FaN0Fb7vJRWrApfU0JgSqifRCfjNza1pSTxLc8kD3oZ+an88nzVzw="; // String s = "azwa1HWeAjiP2Y2rIJot/cgi9Li31Rs92ycpv/vBYf3ydprwEJii7ZNYo98mGLWh20JZ0ur43FwhYWQw/uZCPHhGMCg7yK3CIqpEMSzzUxXLVxMf8qPmF7wzbNQ6LG+YVDwGHMr+R3r4sKYpw41ZxQzEFd61c7tNqZ9oaouBL3A="; String s1 = publicKeyDecrypt(s, publicKey,point); System.out.println("前端解密出来显示的数据\n"+s1); } /** * 随机生成密钥对 * * @throws NoSuchAlgorithmException * @param point */ public static Map<String, String> genKeyPair(String point) throws NoSuchAlgorithmException { log.info("{}|开始生成公私钥",point); // KeyPairGenerator类用于生成公钥和私钥对，基于RSA算法生成对象 KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance("RSA"); // 初始化密钥对生成器，密钥大小为96-1024位 keyPairGen.initialize(1024, new SecureRandom()); // 生成一个密钥对，保存在keyPair中 KeyPair keyPair = keyPairGen.generateKeyPair(); RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate(); // 得到私钥 RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic(); // 得到公钥 String publicKeyString = new String(Base64.encodeBase64(publicKey.getEncoded())); // 得到私钥字符串 String privateKeyString = new String(Base64.encodeBase64((privateKey.getEncoded()))); // 将公钥和私钥保存到Map Map<String, String> map = new HashMap<>(); map.put("publicKey", publicKeyString); map.put("privateKey", privateKeyString); log.info("{}|生成的公私钥|map:{}",point,map); return map; } /** * RSA公钥加密 * * @param str 加密字符串 * @param publicKey 公钥 * @return 密文 * @throws Exception 加密过程中的异常信息 */ public static String publicKeyEncrypt(String str, String publicKey,String point) throws Exception { log.info("{}|RSA公钥加密前的数据|str:{}|publicKey:{}",point,str,publicKey); //base64编码的公钥 byte[] decoded = Base64.decodeBase64(publicKey); RSAPublicKey pubKey = (RSAPublicKey) KeyFactory.getInstance("RSA"). generatePublic(new X509EncodedKeySpec(decoded)); //RSA加密 Cipher cipher = Cipher.getInstance("RSA"); cipher.init(Cipher.ENCRYPT_MODE, pubKey); String outStr = Base64.encodeBase64String(cipher.doFinal(str.getBytes("UTF-8"))); log.info("{}|公钥加密后的数据|outStr:{}",point,outStr); return outStr; } /** * RSA私钥解密 * * @param str 加密字符串 * @param privateKey 私钥 * @param point * @return 铭文 * @throws Exception 解密过程中的异常信息 */ public static String privateKeyDecrypt(String str, String privateKey, String point) throws Exception { log.info("{}|RSA私钥解密前的数据|str:{}|privateKey:{}",point,str,privateKey); //64位解码加密后的字符串 byte[] inputByte = Base64.decodeBase64(str.getBytes("UTF-8")); //base64编码的私钥 byte[] decoded = Base64.decodeBase64(privateKey); RSAPrivateKey priKey = (RSAPrivateKey) KeyFactory.getInstance("RSA") .generatePrivate(new PKCS8EncodedKeySpec(decoded)); //RSA解密 Cipher cipher = Cipher.getInstance("RSA"); cipher.init(Cipher.DECRYPT_MODE, priKey); String outStr = new String(cipher.doFinal(inputByte)); log.info("{}|RSA私钥解密后的数据|outStr:{}",point,outStr); return outStr; } /** * RSA私钥加密 * * @param str * @param privateKey * @return * @throws Exception */ public static String privateKeyEncrypt(String str, String privateKey,String point) throws Exception { log.info("{}|RSA私钥加密前的数据|str:{}|publicKey:{}",point,str,privateKey); //base64编码的公钥 byte[] decoded = Base64.decodeBase64(privateKey); PrivateKey priKey = KeyFactory.getInstance("RSA"). generatePrivate(new PKCS8EncodedKeySpec(decoded)); //RSA加密 Cipher cipher = Cipher.getInstance("RSA"); cipher.init(Cipher.ENCRYPT_MODE, priKey); String outStr = Base64.encodeBase64String(cipher.doFinal(str.getBytes())); log.info("{}|RSA私钥加密后的数据|outStr:{}",point,outStr); return outStr; } /** * RSA公钥解密 * * @param str * @param publicKey * @return * @throws Exception */ public static String publicKeyDecrypt(String str, String publicKey,String point) throws Exception { log.info("{}|RSA公钥解密前的数据|str:{}|publicKey:{}",point,str,publicKey); //64位解码加密后的字符串 byte[] inputByte = Base64.decodeBase64(str.getBytes("UTF-8")); //base64编码的私钥 byte[] decoded = Base64.decodeBase64(publicKey); PublicKey pubKey = KeyFactory.getInstance("RSA") .generatePublic(new X509EncodedKeySpec(decoded)); //RSA解密 Cipher cipher = Cipher.getInstance("RSA"); cipher.init(Cipher.DECRYPT_MODE, pubKey); String outStr = new String(cipher.doFinal(inputByte)); log.info("{}|RSA公钥解密后的数据|outStr:{}",point,outStr); return outStr; } }

通过RSA进行前端与后端的交互， 前端获取到公钥 后端获取到私钥 前端发起请求，通过公钥加密，后端用私钥解密 后端通知前端，通过私钥加密，前端通过公钥解密

前端通过公钥解密的逻辑没有测试过，找到的资源地址为： https://github.com/kjur/jsrsasign/blob/master/src/rsasign-1.2.js#L234

错误信息： Data must not be longer than 128 bytes 当加解密的数据长度过长，需要对数据进行分割 加密则117字节，解密则128字节

/** * RSA公钥加密 * * @param str 加密字符串 * @param publicKey 公钥 * @return 密文 * @throws Exception 加密过程中的异常信息 */ public static String publicKeyEncrypt(String str, String publicKey, String point) throws Exception { log.info("{}|RSA公钥加密前的数据|str:{}|publicKey:{}", point, str, publicKey); //base64编码的公钥 byte[] decoded = Base64.decodeBase64(publicKey); RSAPublicKey pubKey = (RSAPublicKey) KeyFactory.getInstance("RSA"). generatePublic(new X509EncodedKeySpec(decoded)); //RSA加密 Cipher cipher = Cipher.getInstance("RSA"); cipher.init(Cipher.ENCRYPT_MODE, pubKey); //当长度过长的时候，需要分割后加密 117个字节 byte[] resultBytes = getMaxResultEncrypt(str, point, cipher); String outStr = Base64.encodeBase64String(resultBytes); log.info("{}|公钥加密后的数据|outStr:{}", point, outStr); return outStr; } private static byte[] getMaxResultEncrypt(String str, String point, Cipher cipher) throws IllegalBlockSizeException, BadPaddingException { byte[] inputArray = str.getBytes(); int inputLength = inputArray.length; log.info("{}|加密字节数|inputLength:{}", point, inputLength); // 最大加密字节数，超出最大字节数需要分组加密 int MAX_ENCRYPT_BLOCK = 117; // 标识 int offSet = 0; byte[] resultBytes = {}; byte[] cache = {}; while (inputLength - offSet > 0) { if (inputLength - offSet > MAX_ENCRYPT_BLOCK) { cache = cipher.doFinal(inputArray, offSet, MAX_ENCRYPT_BLOCK); offSet += MAX_ENCRYPT_BLOCK; } else { cache = cipher.doFinal(inputArray, offSet, inputLength - offSet); offSet = inputLength; } resultBytes = Arrays.copyOf(resultBytes, resultBytes.length + cache.length); System.arraycopy(cache, 0, resultBytes, resultBytes.length - cache.length, cache.length); } return resultBytes; } /** * RSA私钥解密 * * @param str 加密字符串 * @param privateKey 私钥 * @param point * @return 铭文 * @throws Exception 解密过程中的异常信息 */ public static String privateKeyDecrypt(String str, String privateKey, String point) throws Exception { log.info("{}|RSA私钥解密前的数据|str:{}|privateKey:{}", point, str, privateKey); //64位解码加密后的字符串 byte[] inputByte = Base64.decodeBase64(str.getBytes("UTF-8")); //base64编码的私钥 byte[] decoded = Base64.decodeBase64(privateKey); RSAPrivateKey priKey = (RSAPrivateKey) KeyFactory.getInstance("RSA") .generatePrivate(new PKCS8EncodedKeySpec(decoded)); //RSA解密 Cipher cipher = Cipher.getInstance("RSA"); cipher.init(Cipher.DECRYPT_MODE, priKey); // String outStr = new String(cipher.doFinal(inputByte)); //当长度过长的时候，需要分割后解密 128个字节 String outStr = new String(getMaxResultDecrypt(str, point, cipher)); log.info("{}|RSA私钥解密后的数据|outStr:{}", point, outStr); return outStr; } private static byte[] getMaxResultDecrypt(String str, String point, Cipher cipher) throws IllegalBlockSizeException, BadPaddingException, UnsupportedEncodingException { byte[] inputArray = Base64.decodeBase64(str.getBytes("UTF-8")); int inputLength = inputArray.length; log.info("{}|解密字节数|inputLength:{}", point, inputLength); // 最大解密字节数，超出最大字节数需要分组加密 int MAX_ENCRYPT_BLOCK = 128; // 标识 int offSet = 0; byte[] resultBytes = {}; byte[] cache = {}; while (inputLength - offSet > 0) { if (inputLength - offSet > MAX_ENCRYPT_BLOCK) { cache = cipher.doFinal(inputArray, offSet, MAX_ENCRYPT_BLOCK); offSet += MAX_ENCRYPT_BLOCK; } else { cache = cipher.doFinal(inputArray, offSet, inputLength - offSet); offSet = inputLength; } resultBytes = Arrays.copyOf(resultBytes, resultBytes.length + cache.length); System.arraycopy(cache, 0, resultBytes, resultBytes.length - cache.length, cache.length); } return resultBytes; }
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