一、客戶端(APP)和服務端驗籤機制
1.背景
在以前傳統項目中,當用戶輸入完正確的用戶名和密碼之後,服務端會在session存入用戶的信息,即客戶端登錄成功後,服務端給其分配一個sessionId,返回給客戶端,以後每次客戶端請求帶着sessionId。這種方式進行交互的時候必然存在安全風險,上述登錄流程, 我們服務器判斷用戶的登錄狀態, 完全依賴於sessionId,一旦其被截獲, 黑客就能夠模擬出用戶的請求。例如(我們產品中以前真實發生過的):現在wifi隨處可見,用戶通過wifi連接到公網,請求我們服務器,這樣在外連接不安全的wifi的時候,黑客就有機可趁了,他通過網絡傳輸工具,在用戶登錄我們APP之後,攔截獲取到我們傳給客戶端的sessionId;並通過用戶在APP中的操作,抓取到一些關鍵性的請求地址,進行僞造攻擊。
基於此,我引入了當時比較流行的解決方案,通過RAS祕鑰對加密並引入token機制,防止被惡意攔截攻擊。方案如下:
1)客戶端在第一次進入的時候會進行初始化,服務端通過RSA生產祕鑰對A,私鑰A存在服務端,公鑰A傳給客戶端;
2)用戶在登錄時,將密碼用公鑰A進行RSA加密,並初始化RSA祕鑰對B,將公鑰B,用戶名,加密後的密碼傳給服務端。服務端通過私鑰A進行解密驗證密碼,通過後生產唯一字符串token,並通過公鑰B進行加密token和session一起傳給客戶端;
3)客戶端通過私鑰B進行解密獲得真正的token,存在上下文中,以後每次請求,都用公鑰A進行加密傳給服務端進行驗證
這樣,就算被攔截,黑客獲取到的都是密文,直接用戶僞造請求服務端的校驗會報錯,解密??呵呵(破解這算法要買最好的計算機和花幾個月長則幾年的時間,取決於你祕鑰的長度),難道太大,成本太高,黑客也會放棄攻擊的。(就像爬蟲和反爬蟲,當爬蟲成本遠大於收益的時候,爬蟲者也會放棄爬去該網站(保護成功),反正人家不爬你爬誰)
二、RSA加密(JAVA端實現)
package com.xiatian.scb.demo.util;
import org.springframework.util.Base64Utils;
import javax.crypto.Cipher;
import java.io.ByteArrayOutputStream;
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;
/**
* 〈一句話功能簡述〉<br>
* 〈功能詳細描述〉
*
* @author 18043622 2018/8/22
* @see [相關類/方法](可選)
* @since [產品/模塊版本] (可選)
*/
public class RSAUtils {
/** *//**
* 加密算法RSA
*/
public static final String KEY_ALGORITHM = "RSA";
/** *//**
* 簽名算法
*/
public static final String SIGNATURE_ALGORITHM = "MD5withRSA";
/** *//**
* 獲取公鑰的key
*/
private static final String PUBLIC_KEY = "RSAPublicKey";
/** *//**
* 獲取私鑰的key
*/
private static final String PRIVATE_KEY = "RSAPrivateKey";
/** *//**
* RSA最大加密明文大小
*/
private static final int MAX_ENCRYPT_BLOCK = 117;
/** *//**
* RSA最大解密密文大小
*/
private static final int MAX_DECRYPT_BLOCK = 128;
/** *//**
* <p>
* 生成密鑰對(公鑰和私鑰)
* </p>
*
* @return
* @throws Exception
*/
public static Map<String, Object> genKeyPair() throws Exception {
KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance(KEY_ALGORITHM);
keyPairGen.initialize(1024);
KeyPair keyPair = keyPairGen.generateKeyPair();
RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();
RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();
Map<String, Object> keyMap = new HashMap<>(2);
keyMap.put(PUBLIC_KEY, publicKey);
keyMap.put(PRIVATE_KEY, privateKey);
return keyMap;
}
/** *//**
* <p>
* 用私鑰對信息生成數字簽名
* </p>
*
* @param data 已加密數據
* @param privateKey 私鑰(BASE64編碼)
*
* @return
* @throws Exception
*/
public static String sign(byte[] data, String privateKey) throws Exception {
byte[] keyBytes = Base64Utils.decodeFromString(privateKey);
PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
PrivateKey privateK = keyFactory.generatePrivate(pkcs8KeySpec);
Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);
signature.initSign(privateK);
signature.update(data);
return Base64Utils.encodeToString(signature.sign());
}
/** *//**
* <p>
* 校驗數字簽名
* </p>
*
* @param data 已加密數據
* @param publicKey 公鑰(BASE64編碼)
* @param sign 數字簽名
*
* @return
* @throws Exception
*
*/
public static boolean verify(byte[] data, String publicKey, String sign)
throws Exception {
byte[] keyBytes = Base64Utils.decodeFromString(publicKey);
X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);
KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
PublicKey publicK = keyFactory.generatePublic(keySpec);
Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);
signature.initVerify(publicK);
signature.update(data);
return signature.verify(Base64Utils.decodeFromString(sign));
}
/** *//**
* <P>
* 私鑰解密
* </p>
*
* @param encryptedData 已加密數據
* @param privateKey 私鑰(BASE64編碼)
* @return
* @throws Exception
*/
public static byte[] decryptByPrivateKey(byte[] encryptedData, String privateKey)
throws Exception {
byte[] keyBytes = Base64Utils.decodeFromString(privateKey);
PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
Key privateK = keyFactory.generatePrivate(pkcs8KeySpec);
Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
cipher.init(Cipher.DECRYPT_MODE, privateK);
int inputLen = encryptedData.length;
ByteArrayOutputStream out = new ByteArrayOutputStream();
int offSet = 0;
byte[] cache;
int i = 0;
// 對數據分段解密
while (inputLen - offSet > 0) {
if (inputLen - offSet > MAX_DECRYPT_BLOCK) {
cache = cipher.doFinal(encryptedData, offSet, MAX_DECRYPT_BLOCK);
} else {
cache = cipher.doFinal(encryptedData, offSet, inputLen - offSet);
}
out.write(cache, 0, cache.length);
i++;
offSet = i * MAX_DECRYPT_BLOCK;
}
byte[] decryptedData = out.toByteArray();
out.close();
return decryptedData;
}
/** *//**
* <p>
* 公鑰解密
* </p>
*
* @param encryptedData 已加密數據
* @param publicKey 公鑰(BASE64編碼)
* @return
* @throws Exception
*/
public static byte[] decryptByPublicKey(byte[] encryptedData, String publicKey)
throws Exception {
byte[] keyBytes = Base64Utils.decodeFromString(publicKey);
X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);
KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
Key publicK = keyFactory.generatePublic(x509KeySpec);
Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
cipher.init(Cipher.DECRYPT_MODE, publicK);
int inputLen = encryptedData.length;
ByteArrayOutputStream out = new ByteArrayOutputStream();
int offSet = 0;
byte[] cache;
int i = 0;
// 對數據分段解密
while (inputLen - offSet > 0) {
if (inputLen - offSet > MAX_DECRYPT_BLOCK) {
cache = cipher.doFinal(encryptedData, offSet, MAX_DECRYPT_BLOCK);
} else {
cache = cipher.doFinal(encryptedData, offSet, inputLen - offSet);
}
out.write(cache, 0, cache.length);
i++;
offSet = i * MAX_DECRYPT_BLOCK;
}
byte[] decryptedData = out.toByteArray();
out.close();
return decryptedData;
}
/** *//**
* <p>
* 公鑰加密
* </p>
*
* @param data 源數據
* @param publicKey 公鑰(BASE64編碼)
* @return
* @throws Exception
*/
public static byte[] encryptByPublicKey(byte[] data, String publicKey)
throws Exception {
byte[] keyBytes = Base64Utils.decodeFromString(publicKey);
X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);
KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
Key publicK = keyFactory.generatePublic(x509KeySpec);
// 對數據加密
Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
cipher.init(Cipher.ENCRYPT_MODE, publicK);
int inputLen = data.length;
ByteArrayOutputStream out = new ByteArrayOutputStream();
int offSet = 0;
byte[] cache;
int i = 0;
// 對數據分段加密
while (inputLen - offSet > 0) {
if (inputLen - offSet > MAX_ENCRYPT_BLOCK) {
cache = cipher.doFinal(data, offSet, MAX_ENCRYPT_BLOCK);
} else {
cache = cipher.doFinal(data, offSet, inputLen - offSet);
}
out.write(cache, 0, cache.length);
i++;
offSet = i * MAX_ENCRYPT_BLOCK;
}
byte[] encryptedData = out.toByteArray();
out.close();
return encryptedData;
}
/** *//**
* <p>
* 私鑰加密
* </p>
*
* @param data 源數據
* @param privateKey 私鑰(BASE64編碼)
* @return
* @throws Exception
*/
public static byte[] encryptByPrivateKey(byte[] data, String privateKey)
throws Exception {
byte[] keyBytes = Base64Utils.decodeFromString(privateKey);
PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
Key privateK = keyFactory.generatePrivate(pkcs8KeySpec);
Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
cipher.init(Cipher.ENCRYPT_MODE, privateK);
int inputLen = data.length;
ByteArrayOutputStream out = new ByteArrayOutputStream();
int offSet = 0;
byte[] cache;
int i = 0;
// 對數據分段加密
while (inputLen - offSet > 0) {
if (inputLen - offSet > MAX_ENCRYPT_BLOCK) {
cache = cipher.doFinal(data, offSet, MAX_ENCRYPT_BLOCK);
} else {
cache = cipher.doFinal(data, offSet, inputLen - offSet);
}
out.write(cache, 0, cache.length);
i++;
offSet = i * MAX_ENCRYPT_BLOCK;
}
byte[] encryptedData = out.toByteArray();
out.close();
return encryptedData;
}
/** *//**
* <p>
* 獲取私鑰
* </p>
*
* @param keyMap 密鑰對
* @return
* @throws Exception
*/
public static String getPrivateKey(Map<String, Object> keyMap)
throws Exception {
Key key = (Key) keyMap.get(PRIVATE_KEY);
return Base64Utils.encodeToString(key.getEncoded());
}
/** *//**
* <p>
* 獲取公鑰
* </p>
*
* @param keyMap 密鑰對
* @return
* @throws Exception
*/
public static String getPublicKey(Map<String, Object> keyMap)
throws Exception {
Key key = (Key) keyMap.get(PUBLIC_KEY);
return Base64Utils.encodeToString(key.getEncoded());
}
public static void main(String[] args) throws Exception {
Map<String, Object> keyMap = RSAUtils.genKeyPair();
// 測試RSA
System.err.println("公鑰加密——私鑰解密");
String source = "我喜歡大灰狼,啦啦啦,大灰狼。密文你看不懂哦";
System.out.println("\r加密前文字:\r\n" + source);
byte[] data = source.getBytes();
byte[] encodedData = RSAUtils.encryptByPublicKey(data, RSAUtils.getPublicKey(keyMap));
System.out.println("加密後文字:\r\n" + Base64Utils.encodeToString(encodedData));
byte[] decodedData = RSAUtils.decryptByPrivateKey(encodedData, RSAUtils.getPrivateKey(keyMap));
String target = new String(decodedData);
System.out.println("解密後文字: \r\n" + target);
}
}
輸出結果:
加密前文字:
我喜歡大灰狼,啦啦啦,大灰狼。密文你看不懂哦
加密後文字:
Ap7sY2UnWyfKgqq+SgXDEH8u0XwmybDzdC+o4O2QQl+3aEYz5aUJpGJH7qoxQaEEwkEJMGGeKo6rkXlvi6j+2zJ56CBO34dyq9R6bc2eCZgcz21ghclKHYkOCOTkpKUh9g7BkjFIiUgtrrARlVMt1CmTVtEFn+ToyWq+K6/R3ms=
解密後文字:
我喜歡大灰狼,啦啦啦,大灰狼。密文你看不懂哦
這樣 黑客最多得到密文,他也看不懂的啦
其實,以上token機制爲了以防萬一(黑客在用戶手機上裝了流氓軟件,解開了token明文)。我們也可以做一個token失效機制,每隔5分鐘就更新token一次(失效的token不能通過校驗),做個保護。