Openssl生成RSA证书，Java实现公钥证书加密，私钥证书解密

╰半夏微凉° 2022-03-31 07:10 486阅读 0赞

**1、证书生成过程**

1.  生成RSA私钥：  
    genrsa -out private\_key.pem 1024
2.  把RSA私钥转换成PKCS8格式  
    pkcs8 -topk8 -inform PEM -in private\_key.pem -outform PEM –nocrypt
3.  生成RSA公钥  
    rsa -in private\_key.pem -pubout -out rsa\_public\_key.pem
4.  生成供Java使用的私钥pkcs8\_private\_key.pem  
    pkcs8 -topk8 -in private\_key.pem -out tfs\_private\_key.pem -nocrypt

**2、使用的源码及测试**

import org.apache.commons.codec.binary.Base64;
    import sun.misc.BASE64Decoder;
    import javax.crypto.BadPaddingException;
    import javax.crypto.Cipher;
    import javax.crypto.IllegalBlockSizeException;
    import javax.crypto.NoSuchPaddingException;
    import java.io.*;
    import java.security.*;
    import java.security.interfaces.RSAPrivateKey;
    import java.security.interfaces.RSAPublicKey;
    import java.security.spec.InvalidKeySpecException;
    import java.security.spec.PKCS8EncodedKeySpec;
    import java.security.spec.X509EncodedKeySpec;
    
    public class RSAEncryptUtils {
    	/**
         * 字节数据转字符串专用集合
         */
        private static final char[] HEX_CHAR = {'0', '1', '2', '3', '4', '5', '6',
                '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'};
    
    
        private static final String PRIVATE_KEY = "/tfs_private_key.pem";
    
        private static final String PUBLIC_KEY = "/rsa_public_key.pem";
    
        /**
         * 随机生成密钥对
         */
        public static void genKeyPair(String filePath) {
            // KeyPairGenerator类用于生成公钥和私钥对，基于RSA算法生成对象
            KeyPairGenerator keyPairGen = null;
            try {
                keyPairGen = KeyPairGenerator.getInstance("RSA");
            } catch (NoSuchAlgorithmException e) {
                e.printStackTrace();
            }
            // 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();
            // 得到私钥
            RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();
            // 得到公钥
            RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();
            try {
                // 得到公钥字符串
                Base64 base64 = new Base64();
                String publicKeyString = new String(base64.encode(publicKey.getEncoded()));
                // 得到私钥字符串
                String privateKeyString = new String(base64.encode(privateKey.getEncoded()));
                // 将密钥对写入到文件
                FileWriter pubfw = new FileWriter(filePath + PUBLIC_KEY);
                FileWriter prifw = new FileWriter(filePath + PRIVATE_KEY);
                BufferedWriter pubbw = new BufferedWriter(pubfw);
                BufferedWriter pribw = new BufferedWriter(prifw);
                pubbw.write(publicKeyString);
                pribw.write(privateKeyString);
                pubbw.flush();
                pubbw.close();
                pubfw.close();
                pribw.flush();
                pribw.close();
                prifw.close();
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    
        /**
         * 从文件中输入流中加载公钥
         *
         * @param path 公钥输入流
         * @throws Exception 加载公钥时产生的异常
         */
        public static String loadPublicKeyByFile(String path) throws Exception {
            try {
                BufferedReader br = new BufferedReader(new FileReader(path
                        + PUBLIC_KEY));
                String readLine = null;
                StringBuilder sb = new StringBuilder();
                while ((readLine = br.readLine()) != null) {
                    if (readLine.charAt(0) == '-') {
                        continue;
                    } else {
                        sb.append(readLine);
                        sb.append('\r');
                    }
                }
                br.close();
                return sb.toString();
            } catch (IOException e) {
                throw new Exception("公钥数据流读取错误");
            } catch (NullPointerException e) {
                throw new Exception("公钥输入流为空");
            }
        }
    
        /**
         * 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 {
                BASE64Decoder base64 = new BASE64Decoder();
                byte[] buffer = base64.decodeBuffer(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 path 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
                        + PRIVATE_KEY));
                String readLine = null;
                StringBuilder sb = new StringBuilder();
                while ((readLine = br.readLine()) != null) {
                    if (readLine.charAt(0) == '-') {
                        continue;
                    } else {
                        sb.append(readLine);
                        sb.append('\r');
                    }
                }
                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 {
                BASE64Decoder base64Decoder = new BASE64Decoder();
                byte[] buffer = base64Decoder.decodeBuffer(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();
        }
        
        public static void main(String[] args) throws Exception {
        	 System.out.println("--------------公钥加密私钥解密过程-------------------");
        	 String filepath = "D:/Work/WorkSpace/trunk_remote_dev/tfs-china-eport-api/src/main/resources/cert";
        	 Base64 base64 = new Base64();
        	 String signKey = "{\"name\":\"Ron\",\"part\":\"IT\"}";
             // 公钥加密过程
             byte[] cipherData = RSAEncryptUtils.encrypt(RSAEncryptUtils.loadPublicKeyByStr(RSAEncryptUtils.loadPublicKeyByFile(filepath)),
                     signKey.getBytes());
             String cipher = new String(base64.encode(cipherData));
             // 私钥解密过程
             byte[] res = RSAEncryptUtils.decrypt(RSAEncryptUtils.loadPrivateKeyByStr(RSAEncryptUtils.loadPrivateKeyByFile(filepath)),
                     base64.decode(cipher));
             String restr = new String(res);
             System.out.println("原文：" + signKey);
             System.out.println("密文：" + cipher);
             System.out.println("解密：" + restr);
             System.out.println();
    	}
    }