详解Android端与JavaWeb传输加密（DES+RSA）
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
