一、加密介绍
本文采用对称式加密算法DES和非对称式加密算法RSA结合做数据传输加密的方式。
先说一下对称式加密 DES:对称式加密即使用单钥密码加密的方法，信息的加密和解密使用同一个秘钥，这种方式也称为单秘钥加密。所谓对称就是指加密和解密使用的是同一个秘钥！
常用的对称加密有：DES、IDEA、RC2、RC4、SKIPJACK、RC5、AES算法等。
与对称加密算法不同，非对称加密算法需要两个密钥：公开密钥（publickey）和私有密钥 （privatekey）。公开密钥与私有密钥是一对，如果用公开密钥对数据进行加密，只有用对应的私有密钥才能解密；如果用私有密钥对数据进行加密，那么只有用对应的公开密钥才能解密。因为加密和解密使用的是两个不同的密钥，所以这种算法叫作非对称加密算法。
RSA 公钥加密算法是1977年由Ron Rivest、Adi Shamirh和LenAdleman在（美国麻省理工学院）开发的。RSA取名来自开发他们三者的名字。RSA是目前最有影响力的公钥加密算法，它能够抵抗到目前为止已知的所有密码攻击，已被ISO推荐为公钥数据加密标准。 RSA算法基于一个十分简单的数论事实：将两个大素数相乘十分容易，但那时想要对其乘积进行因式分解却极其困难，因此可以将乘积公开作为加密密钥。
二、ＲＳＡ密钥生成
RSA密钥采用OpenSSL协议进行生成，本文仅简单生成公钥和私钥，如有其它需要可以通过ＣＡ证书进行密钥的生成
１、OpenSSL安装
http://slproweb.com/products/Win32OpenSSL.html
请自行选择32位64位进行下载安装
２、打开工作空间
打开OpenSSL安装目录下的bin，运行OpenSSL.exe进入OpenSSL工作空间
３、密钥生成
①、私钥生成（生成位置位于bin目录下）
genrsa -out rsa_private_key.pem 1024
openssl随机生成了一份私钥，加密长度是1024位。加密长度是指理论上最大允许”被加密的信息“长度的限制，也就是明文的长度限制。随着这个参数的增大（比方说2048），允许的明文长度也会增加，但同时也会造成计算复杂度的极速增长。一般推荐的长度就是1024位（128字节）
JAVA需要使用的私钥需要经过PKCS#8编码，PHP程序不需要
当前私钥格式需要转换为pkcs#8的格式，命令为：
pkcs8 -topk8 -inform PEM -in pkcs8_rsa_private_key.pem -outform PEM -nocrypt
②、公钥生成
rsa -in rsa_private_key.pem -out rsa_public_key.pem -pubout
至此，RSA+DES相关前期准备工作完成
三、Android端配置
本文主要针对数据传输过程进行加密，采取加密Json字符串完成整个加密过程，由此，需要统一传输参数为"data=********&sign="*******************"的格式，如有其它需求请自行更改。
由于本项目网络框架采用Retrofit+OkHttp的实现方式，所以对参数进行加密的过程由OkHttp拦截器来实现
public class EncryptionInterceptor implements Interceptor { private Context mContext; public EncryptionInterceptor(Context context) { this.mContext = context; } @Override public Response intercept(@NonNull Chain chain) throws IOException { Request request = chain.request(); RequestBody oldBody = request.body(); Buffer buffer = new Buffer(); if (oldBody != null) { oldBody.writeTo(buffer); } String strOldBody = buffer.readUtf8(); Map<String, String> map = new HashMap<>(); String dataByte = URLDecoder.decode(strOldBody.substring(5), "utf-8"); try { //获取DES的key byte[] desKey = DESCoder.initKey(); //DES加密数据 byte[] encrypt = DESCoder.encrypt(dataByte.getBytes(), desKey); map.put("data", parseByte2HexStr(encrypt)); //RSA加密 RSAEncrypt rsaEncrypt = new RSAEncrypt(); InputStream inputStream = mContext.getResources().getAssets().open("rsa_public_key.pem"); //rsa设置公钥 rsaEncrypt.loadPublicKey(inputStream); //rsa加密DES的key byte[] rsaData = rsaEncrypt.encrypt(rsaEncrypt.getPublicKey(), desKey); map.put("sign", parseByte2HexStr(rsaData)); } catch (Exception e) { e.printStackTrace(); } FormBody body = new FormBody.Builder().add("data", map.get("data")).add("sign", map.get("sign")).build(); request = request.newBuilder().header("Content-Type", body.contentType().type()).header("Content-Length", String.valueOf(body.contentLength())).method(request.method(), body).build(); return chain.proceed(request); } /** * 将二进制转换成16进制 * * @since v1.0 */ private static String parseByte2HexStr(byte buf[]) { StringBuilder sb = new StringBuilder(); for (byte aBuf : buf) { String hex = Integer.toHexString(aBuf & 0xFF); if (hex.length() == 1) { hex = '0' + hex; } sb.append(hex.toUpperCase()); } return sb.toString(); } /** * 按照key排序得到参数列表字符串 * * @param paramValues 参数map对象 * @return 参数列表字符串 */ public static String getParamsOrderByKey(Map<String, String> paramValues) { String params = ""; List<String> paramNames = new ArrayList<>(paramValues.size()); paramNames.addAll(paramValues.keySet()); Collections.sort(paramNames); for (String paramName : paramNames) { if (params.equals("")) { params += paramName + "=" + paramValues.get(paramName); } else { params += "&" + paramName + "=" + paramValues.get(paramName); } } return params; } /** * 将16进制转换为二进制 * * @since v1.0 */ public byte[] parseHexStr2Byte(String hexStr) { if (hexStr.length() < 1) return null; byte[] result = new byte[hexStr.length() / 2]; for (int i = 0; i < hexStr.length() / 2; i++) { int high = Integer.parseInt(hexStr.substring(i * 2, i * 2 + 1), 16); int low = Integer.parseInt(hexStr.substring(i * 2 + 1, i * 2 + 2), 16); result[i] = (byte) (high * 16 + low); } return result; } }
添加OkHttp拦截器
new OkHttpClient.Builder() .addInterceptor(new EncryptionInterceptor(this)) .build();
RSA工具类实现
public class RSAEncrypt { public static final String DEFAULT_PUBLIC_KEY = "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQC1Qcf1zVOuhseFxvo6+FnVvEPs" + "\r" + "Uvczg6oX+HjMNksiiDWcNkbPHfznaPDtgoBY2xF0R8HGHbrT53LNvkj7UMcI48tq" + "\r" + "K+B4YdJHe9SgJVDCCiceLLGtf/ev206qJ/XgKgrLFD+vMmjIB8gQCkZvy/dxhEf1" + "\r" + "aAmoz5tdJhOVdxT7QwIDAQAB" + "\r"; public static final String DEFAULT_PRIVATE_KEY = "MIICdgIBADANBgkqhkiG9w0BAQEFAASCAmAwggJcAgEAAoGBALVBx/XNU66Gx4XG" + "\r" + "+jr4WdW8Q+xS9zODqhf4eMw2SyKINZw2Rs8d/Odo8O2CgFjbEXRHwcYdutPncs2+" + "\r" + "SPtQxwjjy2or4Hhh0kd71KAlUMIKJx4ssa1/96/bTqon9eAqCssUP68yaMgHyBAK" + "\r" + "Rm/L93GER/VoCajPm10mE5V3FPtDAgMBAAECgYAf1hEAHHNhSS0MUzmqV+q3ftzT" + "\r" + "SnM+6hZbJXpaLAMgapo3+NSRFmxQXP9MSEqw0LGNIfloCdrB03o3pv98nOCIZCh7" + "\r" + "PHsU2GhxJ04Qro+wKhK358326KNXCjjqVIBG0xMbJxVhjM2/jjfocxFpe5iD7h53" + "\r" + "c+GvDgUVduAYO4I1GQJBAO21n2aIzQV3mScS1O8BRV+9CmHaDbVHqBetRoB3kJ2U" + "\r" + "piflKTNofwWmTA5A8sKt8WcOz7LsB2SWcp9jNvatxA8CQQDDNCmfo6eix9e5f11K" + "\r" + "Rf8sRiN7XGDzlKkZlmQAN0UtXdTP4AN9cuZrwnntWKysXr/zLntYLGYn9rdrohbD" + "\r" + "9RGNAkBOEsog7iuQcSCfQcMoIN29PSSs0OaRtNBTvniadyrLZuhP0CeBGAAoRd9T" + "\r" + "CyfwoxrXg3jaRkWDVxqcmQSTbq0nAkB8flcRhilSqsuNdYpE5VFxpiXY9jirAKO8" + "\r" + "Our6LEXFQjOIhCEVr+L+1OA4HDa8FA2thXaK7H4WfMXMMmr8fN69AkEAuR0YU9My" + "\r" + "snzWLDWYR5sNp90PhyDSL/HTZHBnebD+JlAYwoYRFYt+tXw0/PEmV2B3thYGPeiZ" + "\r" + "kHKd/TeLIVbxGg==" + "\r"; /** * 私钥 */ private RSAPrivateKey privateKey; /** * 公钥 */ private RSAPublicKey publicKey; /** * 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'}; /** * 获取私钥 * * @return 当前的私钥对象 */ public RSAPrivateKey getPrivateKey() { return privateKey; } /** * 获取公钥 * * @return 当前的公钥对象 */ public RSAPublicKey getPublicKey() { return publicKey; } /** * 随机生成密钥对 */ public void genKeyPair() { KeyPairGenerator keyPairGen = null; try { keyPairGen = KeyPairGenerator.getInstance("RSA"); } catch (NoSuchAlgorithmException e) { e.printStackTrace(); } keyPairGen.initialize(1024, new SecureRandom()); KeyPair keyPair = keyPairGen.generateKeyPair(); this.privateKey = (RSAPrivateKey) keyPair.getPrivate(); this.publicKey = (RSAPublicKey) keyPair.getPublic(); } /** * 从文件中输入流中加载公钥 * * @param in 公钥输入流 * @throws Exception 加载公钥时产生的异常 */ public void loadPublicKey(InputStream in) throws Exception { try { BufferedReader br = new BufferedReader(new InputStreamReader(in)); String readLine = null; StringBuilder sb = new StringBuilder(); while ((readLine = br.readLine()) != null) { if (readLine.charAt(0) == '-') { continue; } else { sb.append(readLine); sb.append('\r'); } } loadPublicKey(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 void loadPublicKey(String publicKeyStr) throws Exception { try { // byte[] buffer = Base64.decode(publicKeyStr.getBytes(), Base64.DEFAULT); BASE64Decoder base64Decoder= new BASE64Decoder(); byte[] buffer= base64Decoder.decodeBuffer(publicKeyStr); KeyFactory keyFactory = KeyFactory.getInstance("RSA"); X509EncodedKeySpec keySpec = new X509EncodedKeySpec(buffer); this.publicKey = (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 * * @return 是否成功 * @throws Exception */ public void loadPrivateKey(InputStream in) throws Exception { try { BufferedReader br = new BufferedReader(new InputStreamReader(in)); String readLine = null; StringBuilder sb = new StringBuilder(); while ((readLine = br.readLine()) != null) { if (readLine.charAt(0) == '-') { continue; } else { sb.append(readLine); sb.append('\r'); } } loadPrivateKey(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 void loadPrivateKey(String privateKeyStr) throws Exception { try { //byte[] buffer = Base64.encode(privateKeyStr.getBytes(), Base64.DEFAULT); BASE64Decoder base64Decoder= new BASE64Decoder(); byte[] buffer= base64Decoder.decodeBuffer(privateKeyStr); PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(buffer); KeyFactory keyFactory = KeyFactory.getInstance("RSA"); this.privateKey = (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"); } } /** * 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 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 { cipher = Cipher.getInstance("RSA"); //Android端无需添加此加密提供者，已默认实现 //cipher = Cipher.getInstance("RSA", new BouncyCastleProvider()); cipher.init(Cipher.ENCRYPT_MODE, publicKey); return cipher.doFinal(plainTextData); } 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"); } } /** * 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 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 { cipher = Cipher.getInstance("RSA"); //Android端无需添加此加密提供者，已默认实现 //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"); } } /** * 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) { RSAEncrypt rsaEncrypt = new RSAEncrypt(); //加载公钥 try { rsaEncrypt.loadPublicKey(RSAEncrypt.DEFAULT_PUBLIC_KEY); System.out.println("加载公钥成功"); } catch (Exception e) { System.err.println(e.getMessage()); System.err.println("加载公钥失败"); } /*try { rsaEncrypt.loadPublicKey(RSAEncrypt.DEFAULT_PUBLIC_KEY); System.out.println("加载公钥成功"); } catch (Exception e) { System.err.println(e.getMessage()); System.err.println("加载公钥失败"); } //加载私钥 try { rsaEncrypt.loadPrivateKey(RSAEncrypt.DEFAULT_PRIVATE_KEY); System.out.println("加载私钥成功"); } catch (Exception e) { System.err.println(e.getMessage()); System.err.println("加载私钥失败"); } try { SecureRandom sr = new SecureRandom(); KeyGenerator kg = KeyGenerator.getInstance("DES"); kg.init(56, sr); SecretKey generateKey = kg.generateKey(); String encodeHexString = Hex.toHexString(generateKey.getEncoded()); System.out.println(encodeHexString); } catch (NoSuchAlgorithmException e) { e.printStackTrace(); } //测试字符串 String encryptStr= "Test String chaijunkun"; try { //加密 long encryptStart = System.currentTimeMillis(); byte[] cipher = rsaEncrypt.encrypt(rsaEncrypt.getPublicKey(), encryptStr.getBytes()); long encryptEnd = System.currentTimeMillis(); System.out.println("密文长度:"+ cipher.length); System.out.println(RSAEncrypt.byteArrayToString(cipher)); System.out.println("加密时间"+ (encryptEnd-encryptStart)); //解密 long decryptStart = System.currentTimeMillis(); byte[] plainText = rsaEncrypt.decrypt(rsaEncrypt.getPrivateKey(), cipher); long decryptEnd = System.currentTimeMillis(); System.out.println("明文长度:"+ plainText.length); System.out.println(RSAEncrypt.byteArrayToString(plainText)); System.out.println("解密时间"+ (decryptEnd-decryptStart)); System.out.println(new String(plainText)); } catch (Exception e) { System.err.println(e.getMessage()); }*/ } }
DES工具类实现
public class DESCoder { /** * 密钥算法 * java 7只支持56位密钥 * Bouncy Castle 支持64位密钥 */ public static final String KEY_ALGORITHM = "DES"; /** * 加密/解密算法 /工作模式/填充方式 */ public static final String CIPHER_ALGORITHM = "DES/ECB/PKCS5Padding"; /** * 转换密钥 * @param key 二进制密钥 * @return key 密钥 * @throws Exception */ private static Key toKey(byte[] key) throws Exception{ //实例化DES密钥材料 DESKeySpec dks = new DESKeySpec(key); //实例化密钥工厂 SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(KEY_ALGORITHM); //生产密钥 SecretKey secretKey = keyFactory.generateSecret(dks); return secretKey; } /** * 解密 * @param data 待解密数据 * @param key 密钥 * @return byte[] 解密数据 * @throws Exception */ public static byte[] decrypt(byte[] data,byte[] key) throws Exception{ //还原密钥 Key k = toKey(key); //实例化 Cipher cipher = Cipher.getInstance(CIPHER_ALGORITHM); //初始化，设置为解密模式 cipher.init(Cipher.DECRYPT_MODE, k); //执行操作 return cipher.doFinal(data); } /** * 加密 * @param data 待加密数据 * @param key 密钥 * @return byte[] 加密数据 * @throws Exception */ public static byte[] encrypt(byte[] data,byte[] key) throws Exception{ //还原密钥 Key k = toKey(key); //实例化 Cipher cipher = Cipher.getInstance(CIPHER_ALGORITHM,new BouncyCastleProvider()); //初始化，设置为加密模式 cipher.init(Cipher.ENCRYPT_MODE,k); //执行操作 return cipher.doFinal(data); } /** * 生产密钥 * java 7只支持56位 密钥 * Bouncy Castle 支持64位密钥 * @return byte[] 二进制密钥 * @throws Exception */ public static byte[] initKey() throws Exception{ /* * 实例化密钥生成器 * 若要使用64位密钥注意替换 * 讲下述代码中的 * KeyGenerator.getInstance(KEY_ALGORITHM); * 替换为 * KeyGenerator.getInstance(KEY_ALGORITHM，"BC"); */ KeyGenerator kg = KeyGenerator.getInstance(KEY_ALGORITHM,new BouncyCastleProvider()); kg.init(64); //生成密钥 SecretKey secretKey = kg.generateKey(); //获得密钥的二进制编码形式 return secretKey.getEncoded(); } }
四、JavaWeb端配置
Web后端只需要在Controller中添加以下代码，接受服务端传递的data和sign，并完成接收的Json字符串转换为实体类即可
/** * 解密所需数据 * * @param data 接受客户端上传的Json格式的数据 * @param sign 接受客户端上传的解密数据的key值 */ public <T> T convertJson(String data, String sign,Class<T> clazz) { System.out.println(data); System.out.println(sign); T tClass = null; try { //rsa加密 RSAEncrypt rsaEncrypt = new RSAEncrypt(); //加载rsa私钥 InputStream in = new FileInputStream(new File("C:\\OpenSSL-Win64\\bin\\pkcs8_rsa_private_key.pem")); rsaEncrypt.loadPrivateKey(in); //获取RSA加密的key的数据，并把该16进制的sign转成byte[],(客户端采用将byte[]转成16进制进行数据上传) byte[] keyBytes = parseHexStr2Byte(sign); //通过RSA解密DES的key值 byte[] rsaKey = rsaEncrypt.decrypt(rsaEncrypt.getPrivateKey(), keyBytes); //通过DES的key值解密需要的json数据 byte[] desData = DESCoder.decrypt(parseHexStr2Byte(data), rsaKey); System.out.println(Arrays.toString(desData)); System.out.println(new String(desData)); tClass = JSON.parseObject(new String(desData), clazz); } catch (Exception e) { e.printStackTrace(); } return tClass; }
五、备注
后续会上传相关Demo到Github
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持脚本之家。