检测当前设备上是否有Secure Enclave可用

Question

有没有一种特定的方法来检测当前设备上是否可以存储在安全飞地中？

Answer 1

这是另一个解决方案：

设备.h

#import <Foundation/Foundation.h>

@interface Device : NSObject

+(BOOL) hasSecureEnclave;
+(BOOL) isSimulator;
+(BOOL) hasBiometrics;

@end

设备.m

#import "Device.h"
#import <LocalAuthentication/LocalAuthentication.h>

@implementation Device

//To check that device has secure enclave or not
+(BOOL) hasSecureEnclave {
    NSLog(@"IS Simulator : %d", [Device isSimulator]);
    return [Device hasBiometrics] && ![Device isSimulator] ;
}

//To Check that this is this simulator
+(BOOL) isSimulator {
    return TARGET_OS_SIMULATOR == 1;
}

//Check that this device has Biometrics features available
+(BOOL) hasBiometrics {

    //Local Authentication Context
    LAContext *localAuthContext = [[LAContext alloc] init];
    NSError *error = nil;

    /// Policies can have certain requirements which, when not satisfied, would always cause
    /// the policy evaluation to fail - e.g. a passcode set, a fingerprint
    /// enrolled with Touch ID or a face set up with Face ID. This method allows easy checking
    /// for such conditions.
    BOOL isValidPolicy = [localAuthContext canEvaluatePolicy:LAPolicyDeviceOwnerAuthenticationWithBiometrics error:&error];

    if (isValidPolicy) {

        if (@available(ios 11.0, *)){
            if (error.code != kLAErrorBiometryNotAvailable){
                isValidPolicy = true;
            } else{
                isValidPolicy = false;
            }
        }else{
            if (error.code != kLAErrorTouchIDNotAvailable){
                isValidPolicy = true;
            }else{
                isValidPolicy = false;
            }
        }
        return isValidPolicy;
    }
    return isValidPolicy;
}

@end

如果您想在Swift 4中找到解决方案，请参考此链接。

Solution in Swift 4

Answer 2

对于开发人员来说，Secure Enclave可以做的只有一件事:创建和保存椭圆曲线加密的私钥，并使用这些密钥加密或解密数据。在iOS 9上，描述椭圆曲线算法的属性不在那里-因此，如果您运行的是iOS 9，那么您可以假定安全飞地不在那里，因为您不能使用它。

在iOS 10和更高版本上，如果存在安全飞地，只有一种方法可以保证正确:在安全飞地中创建椭圆曲线加密密钥，如苹果文档所述。如果此操作失败，并且错误代码为-4 = errSecUnimplemented，则不存在安全飞地。

如果您坚持检查设备列表，则只需要记录为没有Secure Enclave但能够运行iOS 10的设备，因为在iOS 9上它永远不可用。

Answer 3

我自己做的：

+ (BOOL) isDeviceOkForSecureEnclave
    {

    double OSVersionNumber                  = floor(NSFoundationVersionNumber);
    UIUserInterfaceIdiom deviceType         = [[UIDevice currentDevice] userInterfaceIdiom];

    BOOL isOSForSecureEnclave               = OSVersionNumber > NSFoundationVersionNumber_iOS_8_4 ? YES:NO;
    //iOS 9 and up are ready for SE


    BOOL isDeviceModelForSecureEnclave  = NO;

    switch (deviceType) {

        case UIUserInterfaceIdiomPhone:
            //iPhone
            isDeviceModelForSecureEnclave = [self isPhoneForSE];
            break;
        case UIUserInterfaceIdiomPad:
            //iPad
            isDeviceModelForSecureEnclave = [self isPadForSE];

            break;
        default:
            isDeviceModelForSecureEnclave = false;
            break;
    }

    return (isOSForSecureEnclave && isDeviceModelForSecureEnclave) ? YES:NO;
}


/**
 The arrays are models that we know not having SE in hardware, so if the current device is on the list it means it dosent have SE
 */

+ (BOOL) isPhoneForSE
{
    NSString *thisPlatform = [self platform];
    NSArray * oldModels = [NSArray arrayWithObjects:
                           @"x86_64",
                           @"iPhone1,1",
                           @"iPhone1,2",
                           @"iPhone2,1",
                           @"iPhone3,1",
                           @"iPhone3,3",
                           @"iPhone4,1",
                           @"iPhone5,1",
                           @"iPhone5,2",
                           @"iPhone5,3",
                           @"iPhone5,4", nil];

    BOOL isInList = [oldModels containsObject: thisPlatform];
    return !isInList;
}


+ (BOOL) isPadForSE
{
    //iPad Mini 2 is the earliest with SE // "iPad4,4"
    NSString *thisPlatform = [self platform];

    NSArray * oldModels = [NSArray arrayWithObjects:
                           @"x86_64",
                           @"@iPad",
                           @"@iPad1,0",
                           @"@iPad1,1",
                           @"iPad2,1",
                           @"iPad2,2",
                           @"iPad2,3",
                           @"iPad2,4",
                           @"iPad2,5",
                           @"iPad2,6",
                           @"iPad2,7",
                           @"iPad3,1",
                           @"iPad3,2",
                           @"iPad3,3",
                           @"iPad3,4",
                           @"iPad3,5",
                           @"iPad3,6",nil];

    BOOL isInList = [oldModels containsObject: thisPlatform];

    return !isInList;

}


+ (NSString *)platform
{
    size_t size;
    sysctlbyname("hw.machine", NULL, &size, NULL, 0);
    char *machine = malloc(size);
    sysctlbyname("hw.machine", machine, &size, NULL, 0);
    NSString *platform = [NSString stringWithUTF8String:machine];
    free(machine);

    return platform;

}

@end