Unique Identifier of a Mac?

Apple has a technote on uniquely identifying a mac. Here’s a loosely modified version of the code Apple has posted in that technote… don’t forget to link your project against IOKit.framework in order to build this:

#import <IOKit/IOKitLib.h>

- (NSString *)serialNumber
{
    io_service_t    platformExpert = IOServiceGetMatchingService(kIOMasterPortDefault,

    IOServiceMatching("IOPlatformExpertDevice"));
    CFStringRef serialNumberAsCFString = NULL;

    if (platformExpert) {
        serialNumberAsCFString = IORegistryEntryCreateCFProperty(platformExpert,
                                                         CFSTR(kIOPlatformSerialNumberKey),
                                                             kCFAllocatorDefault, 0);
        IOObjectRelease(platformExpert);
    }

    NSString *serialNumberAsNSString = nil;
    if (serialNumberAsCFString) {
        serialNumberAsNSString = [NSString stringWithString:(NSString *)serialNumberAsCFString];
        CFRelease(serialNumberAsCFString);
    }

    return serialNumberAsNSString;
}