How do I detect if an app has been cracked without examining the SignerIdentity?

Question

There used to be a method to check if an application was purchased from the App Store, to protect against cracking:

NSBundle *bundle = [NSBundle mainBundle]; 
NS         


        

Answer 1

I like Mick's answer personally as it's short and simple.

Greg's response isn't valid -- Mick's code only checks whether the App can open that URL so there should be no chance of crashing.

I've implemented the following in one of my apps before which does a more strict check of whether the app is encrypted or not, if it's not it's most likely a cracked app:

From analytics, this method has prevented thousands of pirated users for me and took maybe 5 minutes to implement so the cost of doing it was almost nothing -- for me, I didn't care if it increased sales (which I was sure it wasn't going to anyway--it's more that I don't want people freeloading off of my hard work). In addition, a good amount of my app's content feeds information after figuring out whether the app is pirated or not and returns junk data if it is.

In main.m

#import 
#import 
#import 

#if TARGET_IPHONE_SIMULATOR && !defined(LC_ENCRYPTION_INFO)
#define LC_ENCRYPTION_INFO 0x21
struct encryption_info_command {
    uint32_t cmd;
    uint32_t cmdsize;
    uint32_t cryptoff;
    uint32_t cryptsize;
    uint32_t cryptid;
};
#endif

static BOOL isEncrypted();

static BOOL isEncrypted () {
    const struct mach_header *header;
    Dl_info dlinfo;

    /* Fetch the dlinfo for main() */
    if (dladdr(main, &dlinfo) == 0 || dlinfo.dli_fbase == NULL) {
        //NSLog(@"Could not find main() symbol (very odd)");
        return NO;
    }
    header = dlinfo.dli_fbase;

    /* Compute the image size and search for a UUID */
    struct load_command *cmd = (struct load_command *) (header+1);

    for (uint32_t i = 0; cmd != NULL && i < header->ncmds; i++) {
        /* Encryption info segment */
        if (cmd->cmd == LC_ENCRYPTION_INFO) {
            struct encryption_info_command *crypt_cmd = (struct encryption_info_command *) cmd;
            /* Check if binary encryption is enabled */
            if (crypt_cmd->cryptid < 1) {
                /* Disabled, probably pirated */
                return NO;
            }

            /* Probably not pirated <-- can't say for certain, maybe theres a way around it */
            return YES;
        }

        cmd = (struct load_command *) ((uint8_t *) cmd + cmd->cmdsize);
    }

    /* Encryption info not found */
    return NO;
}