iOS获取设备唯一标识

1、问题引入

在我开发的APP中，需要做设备绑定功能，单用户更换新的设备或者异常登录时，需要后台的配合，做验证码处理。
此处Android的同事的处理方式是获取手机的IMEI码，再用户每次打开APP或者登录成功后做一次验证。Apple考虑用户的隐私问题，iOS 5之后就已经不能获取手机的IMEI码了。虽然有私有API可以获取到IMEI，但是问题来了，即使通过私有API获取到了也是不能上App Store。
针对这种情况，我使用了Apple为开发者提供KeyChain。由于其安全性和可靠性，即使在APP被卸载后，依然不会被删除数据。基于这些特点完全满足了我的功能需求，所以我会手动生成一个唯一标识码并保存到KeyChain中。在用户登录成功之后或者每次打开APP时和服务器做一次验证。

2、如何生成唯一的设备码

其实设备码就是一段字符串，那么该如何保证我所生成的是唯一的呢？此处跟后台的同事沟通后，后台的同事表示，每个用户的ID在后台生成的时候就是唯一的,我的方案是：

// 时间戳 + 设备型号 + 用户ID + 一个随机数

// MARK: - 获取当前时间戳
- (NSString *)currentTimeStr
{
    //获取当前时间0秒后的时间
    NSDate* date = [NSDate dateWithTimeIntervalSinceNow:0];
    // 精确到秒
    NSTimeInterval time = [date timeIntervalSince1970];
    NSString *timeString = [NSString stringWithFormat:@"%.0f", time];
    
    return timeString;
}

//MARK: - 生成随机数
-(int)GetRandomNumber:(int)from tonumber:(int)tonumber
{
    return (from + (arc4random() % (tonumber - from + 1)));
}

//MARK: - 获取设备型号
- (NSString*)deviceModelName
{
    struct utsname systemInfo;
    uname(&systemInfo);
    NSString *deviceModel = [NSString stringWithCString:systemInfo.machine encoding:NSUTF8StringEncoding];
    
    //iPhone 系列
    if ([deviceModel isEqualToString:@"iPhone1,1"])    return @"iPhone 1G";
    if ([deviceModel isEqualToString:@"iPhone1,2"])    return @"iPhone 3G";
    if ([deviceModel isEqualToString:@"iPhone2,1"])    return @"iPhone 3GS";
    if ([deviceModel isEqualToString:@"iPhone3,1"])    return @"iPhone 4";
    if ([deviceModel isEqualToString:@"iPhone3,2"])    return @"Verizon iPhone 4";
    if ([deviceModel isEqualToString:@"iPhone4,1"])    return @"iPhone 4S";
    if ([deviceModel isEqualToString:@"iPhone5,1"])    return @"iPhone 5";
    if ([deviceModel isEqualToString:@"iPhone5,2"])    return @"iPhone 5";
    if ([deviceModel isEqualToString:@"iPhone5,3"])    return @"iPhone 5C";
    if ([deviceModel isEqualToString:@"iPhone5,4"])    return @"iPhone 5C";
    if ([deviceModel isEqualToString:@"iPhone6,1"])    return @"iPhone 5S";
    if ([deviceModel isEqualToString:@"iPhone6,2"])    return @"iPhone 5S";
    if ([deviceModel isEqualToString:@"iPhone7,1"])    return @"iPhone 6 Plus";
    if ([deviceModel isEqualToString:@"iPhone7,2"])    return @"iPhone 6";
    if ([deviceModel isEqualToString:@"iPhone8,1"])    return @"iPhone 6s";
    if ([deviceModel isEqualToString:@"iPhone8,2"])    return @"iPhone 6s Plus";
    if ([deviceModel isEqualToString:@"iPhone9,1"])    return @"iPhone 7 (CDMA)";
    if ([deviceModel isEqualToString:@"iPhone9,3"])    return @"iPhone 7 (GSM)";
    if ([deviceModel isEqualToString:@"iPhone9,2"])    return @"iPhone 7 Plus (CDMA)";
    if ([deviceModel isEqualToString:@"iPhone9,4"])    return @"iPhone 7 Plus (GSM)";
    if ([deviceModel isEqualToString:@"iPhone10,1"])   return @"国行(A1863)、日行(A1906)iPhone 8";
    if ([deviceModel isEqualToString:@"iPhone10,4"])   return @"美版(Global/A1905)iPhone 8";
    if ([deviceModel isEqualToString:@"iPhone10,2"])   return @"国行(A1864)、日行(A1898)iPhone 8 Plus";
    if ([deviceModel isEqualToString:@"iPhone10,5"])   return @"美版(Global/A1897)iPhone 8 Plus";
    if ([deviceModel isEqualToString:@"iPhone10,3"])   return @"iPhone X";
    if ([deviceModel isEqualToString:@"iPhone10,6"])   return @"iPhone X";
    
    //iPod 系列
    if ([deviceModel isEqualToString:@"iPod1,1"])      return @"iPod Touch 1G";
    if ([deviceModel isEqualToString:@"iPod2,1"])      return @"iPod Touch 2G";
    if ([deviceModel isEqualToString:@"iPod3,1"])      return @"iPod Touch 3G";
    if ([deviceModel isEqualToString:@"iPod4,1"])      return @"iPod Touch 4G";
    if ([deviceModel isEqualToString:@"iPod5,1"])      return @"iPod Touch 5G";
    
    
    //iPad 系列
    if ([deviceModel isEqualToString:@"iPad1,1"])      return @"iPad";
    if ([deviceModel isEqualToString:@"iPad2,1"])      return @"iPad 2 (WiFi)";
    if ([deviceModel isEqualToString:@"iPad2,2"])      return @"iPad 2 (GSM)";
    if ([deviceModel isEqualToString:@"iPad2,3"])      return @"iPad 2 (CDMA)";
    if ([deviceModel isEqualToString:@"iPad2,4"])      return @"iPad 2 (32nm)";
    if ([deviceModel isEqualToString:@"iPad2,5"])      return @"iPad mini (WiFi)";
    if ([deviceModel isEqualToString:@"iPad2,6"])      return @"iPad mini (GSM)";
    if ([deviceModel isEqualToString:@"iPad2,7"])      return @"iPad mini (CDMA)";
    
    if ([deviceModel isEqualToString:@"iPad3,1"])      return @"iPad 3(WiFi)";
    if ([deviceModel isEqualToString:@"iPad3,2"])      return @"iPad 3(CDMA)";
    if ([deviceModel isEqualToString:@"iPad3,3"])      return @"iPad 3(4G)";
    if ([deviceModel isEqualToString:@"iPad3,4"])      return @"iPad 4 (WiFi)";
    if ([deviceModel isEqualToString:@"iPad3,5"])      return @"iPad 4 (4G)";
    if ([deviceModel isEqualToString:@"iPad3,6"])      return @"iPad 4 (CDMA)";
    
    if ([deviceModel isEqualToString:@"iPad4,1"])      return @"iPad Air";
    if ([deviceModel isEqualToString:@"iPad4,2"])      return @"iPad Air";
    if ([deviceModel isEqualToString:@"iPad4,3"])      return @"iPad Air";
    if ([deviceModel isEqualToString:@"iPad5,3"])      return @"iPad Air 2";
    if ([deviceModel isEqualToString:@"iPad5,4"])      return @"iPad Air 2";
    if ([deviceModel isEqualToString:@"i386"])         return @"Simulator";
    if ([deviceModel isEqualToString:@"x86_64"])       return @"Simulator";
    
    if ([deviceModel isEqualToString:@"iPad4,4"]
        ||[deviceModel isEqualToString:@"iPad4,5"]
        ||[deviceModel isEqualToString:@"iPad4,6"])      return @"iPad mini 2";
    
    if ([deviceModel isEqualToString:@"iPad4,7"]
        ||[deviceModel isEqualToString:@"iPad4,8"]
        ||[deviceModel isEqualToString:@"iPad4,9"])      return @"iPad mini 3";
    
    return deviceModel;
}

3、使用KeyChain保存生成的设备码

+ (NSMutableDictionary *)getKeychainQuery:(NSString *)service {
  return [NSMutableDictionary dictionaryWithObjectsAndKeys:
          (id)kSecClassGenericPassword,(id)kSecClass,
          service, (id)kSecAttrService,
          service, (id)kSecAttrAccount,
          (id)kSecAttrAccessibleAfterFirstUnlock,(id)kSecAttrAccessible,
          nil];
}

+ (void)save:(NSString *)service data:(id)data {

  NSMutableDictionary *keychainQuery = [self getKeychainQuery:service];
  SecItemDelete((CFDictionaryRef)keychainQuery);
  [keychainQuery setObject:[NSKeyedArchiver archivedDataWithRootObject:data] forKey:(id)kSecValueData];
  SecItemAdd((CFDictionaryRef)keychainQuery, NULL);
}

保存成功之后，再下次要用到时直接从KeyChain中查找；

+ (id)load:(NSString *)service {
    id ret = nil;
    NSMutableDictionary *keychainQuery = [self getKeychainQuery:service];
    [keychainQuery setObject:(id)kCFBooleanTrue forKey:(id)kSecReturnData];
    [keychainQuery setObject:(id)kSecMatchLimitOne forKey:(id)kSecMatchLimit];
    CFDataRef keyData = NULL;
    if (SecItemCopyMatching((CFDictionaryRef)keychainQuery, (CFTypeRef *)&keyData) == noErr) {
        @try {
            ret = [NSKeyedUnarchiver unarchiveObjectWithData:(__bridge NSData *)keyData];
        } @catch (NSException *e) {
            NSLog(@"Unarchive of %@ failed: %@", service, e);
        } @finally {
        }
    }
    if (keyData)
        CFRelease(keyData);
    return ret;
}

当然，这只是我个人在开发中的一个思路，如果有不同解决方案，欢迎提出。
本文Demo请戳这里.