// 獲取需要加密文件的二進(jìn)制數(shù)據(jù)
 NSData *data = [NSData dataWithContentsOfFile:@"/Users/wangpengfei/Desktop/photo/IMG_5551.jpg"];
 // 或 base64EncodedStringWithOptions
 NSData *base64Data = [data base64EncodedDataWithOptions:0];
 // 將加密后的文件存儲(chǔ)到桌面
 [base64Data writeToFile:@"/Users/wangpengfei/Desktop/123" atomically:YES];

 // 獲得加密后的二進(jìn)制數(shù)據(jù)
 NSData *base64Data = [NSData dataWithContentsOfFile:@"/Users/wangpengfei/Desktop/123"];
 // 解密 base64 數(shù)據(jù)
 NSData *baseData = [[NSData alloc] initWithBase64EncodedData:base64Data options:0];
 // 寫(xiě)入桌面
 [baseData writeToFile:@"/Users/wangpengfei/Desktop/IMG_5551.jpg" atomically:YES];

 // 將文件 meinv.jpg 進(jìn)行 base64運(yùn)算之后存儲(chǔ)為 meinv.txt
 base64 meinv.jpg -o meinv.txt
 // 講meinv.txt 解碼生成 meinv.png
 base64 -D meinv.txt -o meinv.png
 // 將字符串 "hello" 進(jìn)行 base 64 編碼 結(jié)果:aGVsbG8=cho "hello" | base64
 // 將 base64編碼之后的結(jié)果 aGVsbG8= 反編碼為字符串
 echo aGVsbG8= | base64 -D

 - (void)readLocalUserInfo {
 // 1. 實(shí)例化偏好設(shè)置對(duì)象
 NSUserDefaults *userDefaults = [NSUserDefaults standardUserDefaults];
 // 2. 取出數(shù)據(jù)進(jìn)行賦值
 self.userName.text = [userDefaults objectForKey:kUserNameKey];
 // 此時(shí)讀取的是加密后的密碼
 self.password.text = [userDefaults objectForKey:kPasswordKey];
}

 - (void)saveLocalUserInfo {
 // 1. 實(shí)例化偏好設(shè)置對(duì)象
 NSUserDefaults *userDefaults = [NSUserDefaults standardUserDefaults];
 // 2. 存儲(chǔ)用戶(hù)名
 [userDefaults setObject:self.userName.text forKey:kUserNameKey];
 // 3. 將密碼進(jìn)行base64 加密
 // 將密碼轉(zhuǎn)化為二進(jìn)制數(shù)據(jù)
 NSData *data = [self.password.text dataUsingEncoding:NSUTF8StringEncoding];
 // 進(jìn)行加密
 NSString *base64Str = [data base64EncodedStringWithOptions:0];
 // 4. 將加密后的密碼存儲(chǔ)到偏好設(shè)置
 [userDefaults setObject:base64Str forKey:kPasswordKey];
 // 5. 為了保證線程的一致性，無(wú)論是存儲(chǔ)還是讀取數(shù)據(jù)，都要進(jìn)行同步
 [userDefaults synchronize];
}

 - (IBAction)btnLoginDidClick:(UIButton *)sender {
 // 如果兩個(gè)文本框均不為空，則進(jìn)行登錄操作
 if (self.userName.text.length && self.password.text.length) {
  // 1. 創(chuàng)建請(qǐng)求
  NSString *urlString = @"http://localhost/login/login.php";
  NSURL *url = [NSURL URLWithString:urlString];
  // POST 請(qǐng)求需要手動(dòng)設(shè)置請(qǐng)求方法，因此為可變請(qǐng)求
  NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
  // 設(shè)置請(qǐng)求方法
  request.HTTPMethod = @"POST";
  // 設(shè)置請(qǐng)求參數(shù)
  NSString *body = [NSString stringWithFormat:@"username=%@&password=%@", self.userName.text, self.password.text];
  // 將字符串轉(zhuǎn)為二進(jìn)制數(shù)據(jù)
  NSData *bodyData = [body dataUsingEncoding:NSUTF8StringEncoding];
  // 設(shè)置請(qǐng)求主體(二進(jìn)制數(shù)據(jù))
  request.HTTPBody = bodyData;
  // 2. 發(fā)送請(qǐng)求
  [[[NSURLSession sharedSession] dataTaskWithRequest:request completionHandler:^(NSData * _Nullable data, NSURLResponse * _Nullable response, NSError * _Nullable error) {
  // 打印請(qǐng)求結(jié)果
  NSLog(@"data:%@", [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding]);
  // 判斷是否登錄成功
  if (data && !error) {
   NSLog(@"網(wǎng)絡(luò)請(qǐng)求成功!");
   NSDictionary *dict = [NSJSONSerialization JSONObjectWithData:data options:0 error:nil];
   if (dict[@"userID"]) {
   [self saveLocalUserInfo];
   }
   //跳轉(zhuǎn)到app主界面，在主線程中發(fā)送通知
   dispatch_async(dispatch_get_main_queue(), ^{
   [[NSNotificationCenter defaultCenter] postNotificationName:@"loginSuccess" object:nil];
   });
  } else {
   NSLog(@"網(wǎng)絡(luò)請(qǐng)求失敗!");
  }
  }] resume];
 } else {
  NSLog(@"用戶(hù)名或密碼不能為空!");
 }
 }

 - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
 // 1. 注冊(cè)登錄成功的通知觀察者
 [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(loginSuccess) name:@"loginSuccess" object:nil];
 // 2. 注冊(cè)登錄成功的通知觀察者
 [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(logoutSuccess) name:@"logoutSuccess" object:nil];
 // 每次app打開(kāi)后，應(yīng)該展示給用戶(hù)哪個(gè)界面
 // 3. 利用偏好設(shè)置中用戶(hù)保存的信息來(lái)判斷用戶(hù)的登錄狀態(tài)
 NSString *userName = [[NSUserDefaults standardUserDefaults] objectForKey:kUserNameKey];
 NSString *password = [[NSUserDefaults standardUserDefaults] objectForKey:kPasswordKey];
 if (userName && password) {
  // 顯示app 主界面
  [self loginSuccess];
 } else {
  [self logoutSuccess];
 }
 return YES;
 }

 - (void)loginSuccess {
 NSLog(@"登錄成功!");
 // 獲取主界面
 UIStoryboard *mainSb = [UIStoryboard storyboardWithName:@"Main" bundle:nil];
 // 切換控制器
 self.window.rootViewController = mainSb.instantiateInitialViewController;
 }

 - (void)logoutSuccess {
 NSLog(@"注銷(xiāo)成功!");
 // 獲取登錄界面
 UIStoryboard *loginSb = [UIStoryboard storyboardWithName:@"Login" bundle:nil];
 // 切換控制器
 self.window.rootViewController = loginSb.instantiateInitialViewController;
 }

 // 1. 清除本地信息
 [[NSUserDefaults standardUserDefaults] removeObjectForKey:kUserNameKey];
 [[NSUserDefaults standardUserDefaults] removeObjectForKey:kPasswordKey];
 // 同步信息
 [[NSUserDefaults standardUserDefaults] synchronize];
 // 2. 發(fā)送信息，切換控制器
 [[NSNotificationCenter defaultCenter] postNotificationName:@"logoutSuccess" object:nil];

 NSString *password = @"WangPengfei";
 password = [password md5String];
 NSLog(@"password1:%@", password);

 NSString *salt = @"234567890-!@#$%^&*()_+QWERTYUIOP{ASDFGHJKL:XCVBNM<>";
 [password stringByAppendingString:salt];
 password = [password md5String];
 NSLog(@"password2:%@", password);

 // 1. 當(dāng)前密碼
 NSString *password = @"zhang";
 // 2. hmacKey值，是對(duì)“WangPengfei” 進(jìn)行 MD5加密之后的值（動(dòng)態(tài)生成的）
 NSString *hmacKey = @"d3bba33b51acaa0a272de7a2f6dfa233";

 // 1. 第一次加密：第一次 HMAC 運(yùn)算
 password = [password hmacMD5StringWithKey:hmacKey];
 // 2.1 獲得當(dāng)前的時(shí)間
 NSDate *date = [NSDate date];
 // 2.2 獲得當(dāng)前時(shí)間的字符串
 // 實(shí)例化時(shí)間格式器
 NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
 // 設(shè)置時(shí)間格式
 formatter.dateFormat = @"yyyy-MM-dd HH:mm";
 // 獲取當(dāng)前時(shí)間（要和服務(wù)器保持一致）
 NSString *dateStr = [formatter stringFromDate:date];
 // 3. 將第一次加密后的密碼與當(dāng)前時(shí)間的字符串拼接在一起
 password = [password stringByAppendingString:dateStr];
 // 4. 進(jìn)行第二次 HMAC 加密
 password = [password hmacMD5StringWithKey:hmacKey];

 NSURL *url = [NSURL URLWithString:@"http://localhost/login/loginhmac.php"];
 // POST 要手動(dòng)設(shè)置方法，因此為可變
 NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url];
 // 設(shè)置請(qǐng)求方法
 request.HTTPMethod = @"POST";
 // 設(shè)置請(qǐng)求體內(nèi)容
 NSString *body = [NSString stringWithFormat:@"username=zhangsan&password=%@", password];
 request.HTTPBody = [body dataUsingEncoding:NSUTF8StringEncoding];

 [[[NSURLSession sharedSession] dataTaskWithRequest:request completionHandler:^(NSData * _Nullable data, NSURLResponse * _Nullable response, NSError * _Nullable error) {
  NSLog(@"%@", [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding]);
 }] resume];

 // 獲取應(yīng)用程序唯一標(biāo)識(shí).
 NSString *bundleId = [NSBundle mainBundle].bundleIdentifier;
 // 利用第三方框架,將用戶(hù)密碼保存在鑰匙串
 [SSKeychain setPassword:self.pwdText.text forService:bundleId account:@"wpf"];

self.pwdText.text = [SSKeychain passwordForService:bundleId account:@"wpf"];

 #import <LocalAuthentication/LocalAuthentication.h>

 float version = [UIDevice currentDevice].systemVersion.floatValue;
 if (version < 8.0 ) // 判斷當(dāng)前系統(tǒng)版本 {
  NSLog(@"系統(tǒng)版本太低,請(qǐng)升級(jí)至最新系統(tǒng)");
  return;
 }

 // 1> 實(shí)例化指紋識(shí)別對(duì)象
 LAContext *laCtx = [[LAContext alloc] init];
 // 2> 判斷當(dāng)前設(shè)備是否支持指紋識(shí)別功能.
 if (![laCtx canEvaluatePolicy:LAPolicyDeviceOwnerAuthenticationWithBiometrics error:NULL]) {
  // 如果設(shè)備不支持指紋識(shí)別功能
  NSLog(@"該設(shè)備不支持指紋識(shí)別功能");
  return;
 };

 [laCtx evaluatePolicy:LAPolicyDeviceOwnerAuthenticationWithBiometrics localizedReason:@"指紋登陸" reply:^(BOOL success, NSError *error) {
  // 如果成功,表示指紋輸入正確.
  if (success) {
   NSLog(@"指紋識(shí)別成功!");
  } else {
   NSLog(@"指紋識(shí)別錯(cuò)誤,請(qǐng)?jiān)俅螄L試");
  }
 }];