JAVA实现RSA加密、解密、加签、验签
1、工具类RSAUtils.java
import java.security.spec.PKCS8EncodedKeySpec; import java.security.spec.X509EncodedKeySpec; import java.io.ByteArrayOutputStream; import javax.crypto.Cipher; import java.security.*; import java.util.*; public class RSAUtils { /** * 加密算法RSA */ public static final String KEY_ALGORITHM = "RSA"; /** * 签名算法 */ public static final String SIGNATURE_ALGORITHM = "SHA256withRSA"; /** * 获取公钥的key */ private static final String PUBLIC_KEY_STR = "PublicKeyStr"; /** * 获取私钥的key */ private static final String PRIVATE_KEY_STR = "PrivateKeyStr"; /** * RSA最大加密明文大小(字节数) */ private static final int MAX_ENCRYPT_BLOCK = 117; /** * RSA最大解密密文大小(字节数) */ private static final int MAX_DECRYPT_BLOCK = 128; /** * @description: 生成公钥私钥 * @date: 2024/1/17 14:47 * @param * @return java.util.Map<java.lang.String,java.lang.String> */ public static Map<String, String> initKeyPair() throws Exception { KeyPairGenerator kpg = KeyPairGenerator.getInstance(KEY_ALGORITHM); kpg.initialize(1024); KeyPair keyPair = kpg.generateKeyPair(); PublicKey publicKey = keyPair.getPublic(); PrivateKey privateKey = keyPair.getPrivate(); String publicKeyStr = encryptBASE64(publicKey.getEncoded()); String privateKeyStr = encryptBASE64(privateKey.getEncoded()); Map<String, String> keyMap = new HashMap<>(); keyMap.put(PUBLIC_KEY_STR, publicKeyStr); keyMap.put(PRIVATE_KEY_STR, privateKeyStr); return keyMap; } /** * @description: 公钥加密 * @date: 2024/1/17 14:49 * @param str 待加密字符串 * @param key 公钥 * @return java.lang.String */ public static String encryptByPublicKey(String str, String key) throws Exception { byte[] data = str.getBytes(); PublicKey publicKey = strToPublicKey(key); Cipher cipher = Cipher.getInstance(KEY_ALGORITHM); cipher.init(Cipher.ENCRYPT_MODE, publicKey); byte[] bytes = dataSegment(data, cipher, MAX_ENCRYPT_BLOCK); return encryptBASE64(bytes); } /** * @description: 私钥解密 * @date: 2024/1/17 14:52 * @param str 待解密字符串 * @param key 私钥 * @return java.lang.String */ public static String decryptByPrivateKey(String str, String key) throws Exception { byte[] data = decryptBASE64(str); PrivateKey privateKey = strToPrivateKey(key); Cipher cipher = Cipher.getInstance(KEY_ALGORITHM); cipher.init(Cipher.DECRYPT_MODE, privateKey); byte[] bytes = dataSegment(data, cipher, MAX_DECRYPT_BLOCK); return new String(bytes); } /** * @description: 私钥加密 * @date: 2024/1/17 14:58 * @param str 待加密字符串 * @param key 私钥 * @return java.lang.String */ public static String encryptByPrivateKey(String str, String key) throws Exception { byte[] data = str.getBytes(); PrivateKey privateKey = strToPrivateKey(key); Cipher cipher = Cipher.getInstance(KEY_ALGORITHM); cipher.init(Cipher.ENCRYPT_MODE, privateKey); byte[] bytes = dataSegment(data, cipher, MAX_ENCRYPT_BLOCK); return encryptBASE64(bytes); } /** * @description: 公钥解密 * @date: 2024/1/17 15:23 * @param str 待解密字符串 * @param key 公钥 * @return java.lang.String */ public static String decryptByPublicKey(String str, String key) throws Exception { byte[] data = decryptBASE64(str); PublicKey publicKey = strToPublicKey(key); Cipher cipher = Cipher.getInstance(KEY_ALGORITHM); cipher.init(Cipher.DECRYPT_MODE, publicKey); byte[] bytes = dataSegment(data, cipher, MAX_DECRYPT_BLOCK); return new String(bytes); } /** * @description: 使用私钥对数据进行数字签名 * @date: 2024/1/17 15:36 * @param str 待加签字符串 * @param privateKey 私钥 * @return java.lang.String */ public static String sign(String str, String privateKey) throws Exception { byte[] data = str.getBytes(); PrivateKey priKey = strToPrivateKey(privateKey); Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM); signature.initSign(priKey); signature.update(data); byte[] bytes = signature.sign(); return encryptBASE64(bytes); } /** * @description: 使用公钥对数据验证签名 * @date: 2024/1/17 15:46 * @param str 待验签字符串(即要加签的内容) * @param publicKey 公钥 * @param sign 数据签名 * @return boolean */ public static boolean verify(String str, String publicKey, String sign) throws Exception { byte[] data = str.getBytes(); byte[] signBytes = decryptBASE64(sign); PublicKey pubKey = strToPublicKey(publicKey); Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM); signature.initVerify(pubKey); signature.update(data); return signature.verify(signBytes); } /** * @description: 对数据进行分段加密或解密 * @date: 2024/1/17 16:11 * @param data * @param cipher * @param maxBlock * @return byte[] */ private static byte[] dataSegment(byte[] data, Cipher cipher, int maxBlock) throws Exception{ byte[] toByteArray; int inputLen = data.length; ByteArrayOutputStream out = new ByteArrayOutputStream(); int offSet = 0; int i = 0; byte[] cache; // 对数据分段加密解密 while (inputLen - offSet > 0) { int var = inputLen - offSet > maxBlock ? maxBlock : inputLen - offSet; cache = cipher.doFinal(data, offSet, var); out.write(cache, 0, cache.length); i++; offSet = i * maxBlock; } toByteArray = out.toByteArray(); out.close(); return toByteArray; } /** * @description: 获取私钥 * @date: 2024/1/17 14:57 * @param str 私钥字符串 * @return java.security.PrivateKey */ private static PrivateKey strToPrivateKey(String str) throws Exception { PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(decryptBASE64(str)); KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM); PrivateKey privateKey = keyFactory.generatePrivate(pkcs8KeySpec); return privateKey; } /** * @description: 获取公钥 * @date: 2024/1/17 14:57 * @param str 公钥字符串 * @return java.security.PrivateKey */ private static PublicKey strToPublicKey(String str) throws Exception { X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(decryptBASE64(str)); KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM); PublicKey publicKey = keyFactory.generatePublic(x509KeySpec); return publicKey; } /** * @description: 字节数组转字符串 * @date: 2024/1/17 14:59 * @param bytes 字节数组 * @return java.lang.String */ private static String encryptBASE64(byte[] bytes) { return Base64.getEncoder().encodeToString(bytes); } /** * @description: 字符串转字节数组 * @date: 2024/1/17 15:00 * @param str 字符串 * @return byte[] */ private static byte[] decryptBASE64(String str) { return Base64.getDecoder().decode(str); } public static void main(String[] args) throws Exception { // 获取公钥私钥 Map<String, String> keyMap = initKeyPair(); String publicKey = keyMap.get(PUBLIC_KEY_STR); String privateKey = keyMap.get(PRIVATE_KEY_STR); System.out.println("公钥: " + publicKey); System.out.println("私钥: " + privateKey); String data = "123456"; System.out.println("源数据: " + data); // 公钥加密私钥解密 String encryptData = encryptByPublicKey(data, publicKey); String decryptData = decryptByPrivateKey(encryptData, privateKey); System.out.println("公钥加密结果: " + encryptData); System.out.println("私钥解密结果: " + decryptData); System.out.println(); // 私钥加密公钥解密 String encryptData2 = encryptByPrivateKey(data, privateKey); String decryptData2 = decryptByPublicKey(encryptData2, publicKey); System.out.println("私钥加密结果: " + encryptData2); System.out.println("公钥解密结果: " + decryptData2); System.out.println(); // 私钥加签公钥验签 String data2 = "abc123369"; String sign = sign(data2, privateKey); boolean flag = verify(data2, publicKey, sign); System.out.println("私钥加签结果: " + sign); System.out.println("公钥验签结果: " + flag); } }
2、测试结果
