iOS小技能：敏感逻辑的保护方案

@interface KNUtil : NSObject
/**
 把函数名隐藏在结构体里，以函数指针成员的形式存储。
 编译后，只留了下地址，去掉了名字和参数表，提高了逆向成本和攻击门槛.
 */
typedef struct _util {
    void (*cign)(char *kns[],unsigned int kncount, const char *knkey, unsigned char *knput);
}CNtKNil_t ;
#define SharedUtilStruct ([KNUtil sharedUtil])//提供给外围的接口
+ (CNtKNil_t *)sharedUtil;

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
//留给读者自己实践

SharedUtilStruct->cign(key ,count,knkey, knput);

2021-04-14 17:28:28.762113+0800 SignWithjsKey[23919:2084235] getGyqAppParams: {"api_version":"v1.1.4","appid":"3","time":"1618392508","operator":"中国电信","user_id":"https:\/\/kunnan.blog.csdn.net\/","vn":"1.0","device_id":"b2d4b9fba63ba7b47dbf27","channel":"default","device_name":"iPhone8,1","os":"iOS","sign":"b2ad581d2e30730f3aed506fc7593957","openudid":"0dce01d7424ac89e920e847e96","token":"#公号：iOS逆向","root":"1","idfv":"-D089-4021-82A9-65D8C711","height":"1334","width":"750","xyz":"0.00697,0.007675,-1.009369","os_version":"14.0","network":"no_network","vc":"1","idfa":"-3693-4940-3C59E53FA55"}

-rw-r--r--@  1 mac  staff   1167  7 29  2021 .gitignore
 com.apple.TextEncoding    15 
 com.apple.lastuseddate#PS    16 
 com.apple.quarantine    21 
 
-rw-r--r--@  1 mac  staff  10244  3 31 18:24 .DS_Store
 com.apple.FinderInfo    32 
 com.apple.quarantine    21 

#include <sys/xattr.h>

int setxattr(const char *path, const char *name, const void *value, size_t size, u_int32_t position, int options);

int removexattr(const char *path, const char *name, int options);

ssize_t listxattr(const char *path, char *namebuff, size_t size, int options);

ssize_t getxattr(const char *path, const char *name, void *value, size_t size, u_int32_t position, int options);

- (BOOL)setResourceValues:(NSDictionary<NSURLResourceKey, id> *)keyedValues error:(NSError **)error API_AVAILABLE(macos(10.6), ios(4.0), watchos(2.0), tvos(9.0));

FOUNDATION_EXPORT NSURLResourceKey const NSURLIsExcludedFromBackupKey        API_AVAILABLE(macos(10.8), ios(5.1), watchos(2.0), tvos(9.0)); // true if resource should be excluded from backups, false otherwise (Read-write, value type boolean NSNumber). This property is only useful for excluding cache and other application support files which are not needed in a backup. Some operations commonly made to user documents will cause this property to be reset to false and so this property should not be used on user documents.

#include <sys/xattr.h>

if (!&NSURLIsExcludedFromBackupKey) {
    // iOS <= 5.0.1
    const char *filePath = [[URL path] fileSystemRepresentation];
    const char *name = "com.apple.MobileBackup";
    u_int8_t value = 1;
    int result = setxattr(filePath, name, &value, sizeof(value), 0, 0);
} else {
    // iOS >= 5.1，
    NSError *error = nil;
    [URL setResourceValue:@YES
                   forKey:NSURLIsExcludedFromBackupKey
                    error:&error];
}

//https://kunnan.blog.csdn.net
//HexStrToString https://tool.lu/hexstr/
#define KNfir @"68747470733a2f2f"
#define KNfir1 @"6b756e6e616e2e626c6f672e6373646e"
#define KNfir2 @"2e6e6574"
#define key4pay [NSString stringWithFormat:@"%@%@%@",KNfir,KNfir1,KNfir2]
#define key4paystr [GeneralUtil convertHexStrToString:key4Unionpay]

+(NSString *)translate:(NSString *)content{
    return  [GeneralUtil convertHexStrToString:content];
}

//

#import "GeneralUtil.h"

@implementation GeneralUtil


+ (BOOL)isBlankString:(NSString *)string {
    if (string == nil || string == NULL) {
        return YES;
    }
    if ([string isKindOfClass:[NSNull class]]) {
        return YES;
    }
    if ([[string stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]] length]==0) {
        return YES;
    }
    return NO;
}




+ (NSString *)convertHexStrToString:(NSString *)str {
    if (!str || [str length] == 0) {
        return nil;
    }
    
    NSMutableData *hexData = [[NSMutableData alloc] initWithCapacity:8];
    NSRange range;
    if ([str length] % 2 == 0) {
        range = NSMakeRange(0, 2);
    } else {
        range = NSMakeRange(0, 1);
    }
    for (NSInteger i = range.location; i < [str length]; i += 2) {
        unsigned int anInt;
        NSString *hexCharStr = [str substringWithRange:range];
        NSScanner *scanner = [[NSScanner alloc] initWithString:hexCharStr] ;
        
        [scanner scanHexInt:&anInt];
        NSData *entity = [[NSData alloc] initWithBytes:&anInt length:1];
        [hexData appendData:entity];
        
        range.location += range.length;
        range.length = 2;
    }
    NSString *string = [[NSString alloc]initWithData:hexData encoding:NSUTF8StringEncoding];
    return string;
    
    
}


@end

#define run OmWJoTZfCqoPshvr
#define iosre egnjoOFDrFiQVRgr