I already proposed a sample code in Objective-C in "PCSC sample in Objective-C". This code used the asynchronous version of sendIns. The API is:
- (void)sendIns:(UInt8)ins
p1:(UInt8)p1
p2:(UInt8)p2
data:(NSData *)requestData
le:(NSNumber *)le
reply:(void (^)(NSData *replyData, UInt16 sw, NSError *error))reply;The method returns immediately and a callback
reply block is executed when the card response is received.We will now use the synchronous version of sendIns. The API is:
- (NSData *)sendIns:(UInt8)ins
p1:(UInt8)p1
p2:(UInt8)p2
data:(NSData *)requestData
le:(NSNumber *)le
sw:(UInt16 *)sw
error:(NSError * _Nullable *)error;Crypto Token Kit API
In Yosemite (Mac OS X 10.10) Apple introduced a new API to access smart cards. See OS X Yosemite and smart cards status.This API is not a wrapper above PC/SC. It is the native API to be used on macOS. You do not need to install it, it comes with the OS.
Since PC/SC is not used here the blog title may be misleading. So I used " " around PC/SC this time.
Source code
Create a new Cocoa application in Xcode. You need to enable the App Sandbox and add/set thecom.apple.security.smartcard entitlement to yes.My sample HellloWorld application does not use Cocoa. It is a text only application.
#import <CryptoTokenKit/CryptoTokenKit.h> int main(int argc, const char * argv[]) { TKSmartCardSlotManager * mngr; mngr = [TKSmartCardSlotManager defaultManager]; // Use the first reader/slot found NSString *slotName = (NSString *)mngr.slotNames[0]; NSLog(@"slotName: %@", slotName); dispatch_semaphore_t sem = dispatch_semaphore_create(0); // connect to the slot [mngr getSlotWithName:slotName reply:^(TKSmartCardSlot *slot) { // connect to the card TKSmartCard *card = [slot makeSmartCard]; if (nil == card) { NSLog(@"No card found"); // signals end of getSlotWithName block dispatch_semaphore_signal(sem); return; } // begin a session [card beginSessionWithReply:^(BOOL success, NSError *error) { if (success) { NSData *response; UInt16 sw; NSString *newString; // explicitly set the CLA byte even if 0 is already the default value card.cla = 0x00; // send 1st APDU uint8_t aid[] = {0xA0, 0x00, 0x00, 0x00, 0x62, 0x03, 0x01, 0x0C, 0x06, 0x01}; NSData *data = [NSData dataWithBytes:aid length:sizeof aid]; response = [card sendIns:0xA4 p1:0x04 p2:0x00 data:data le:nil sw:&sw error:&error]; if (nil == response) { NSLog(@"sendIns error: %@", error); goto out; } NSLog(@"Response: %@ 0x%04X", response, sw); // send 2nd APDU response = [card sendIns:0x00 p1:0x00 p2:0x00 data:nil le:@0 sw:&sw error:&error]; if (nil == response) { NSLog(@"sendIns error: %@", error); goto out; } NSLog(@"Response: %@ 0x%04X", response, sw); newString = [[NSString alloc] initWithData:response encoding:NSASCIIStringEncoding]; NSLog(@"%@", newString); out: // end the session [card endSession]; } else { NSLog(@"Session error: %@", error); } // signals end of beginSessionWithReply block dispatch_semaphore_signal(sem); }]; }]; // wait for the asynchronous blocks to finish dispatch_semaphore_wait(sem, DISPATCH_TIME_FOREVER); return 0; }
Output
2017-03-31 10:54:24.990581+0200 HelloWorld[19931:85555] slotName: Gemalto PC Twin Reader 2017-03-31 10:54:25.103855+0200 HelloWorld[19931:85584] Response: <> 0x9000 2017-03-31 10:54:25.115946+0200 HelloWorld[19931:85584] Response: <48656c6c 6f20776f="" 726c6421=""> 0x9000 2017-03-31 10:54:25.115993+0200 HelloWorld[19931:85584] Hello world!
Comments
Compared to the previous Objective-C sample in "PCSC sample in Objective-C" this code has some improvements/bugs fixes:[card endSession];is called.
This is needed to close the session started by[card beginSessionWithReply:...].- The main thread is waiting for the callbacks from
[mngr getSlotWithName:...]and[card beginSessionWithReply:...]to finish using a semaphore (instead of asleep()).
The CryptoTokenKit API provides a inSessionWithError:executeBlock: to synchronously begin a session instead of using beginSessionWithReply: and endSession. But this method has some limitations/bugs and is not (yet) easy to use. I may use it in a next sample code when it will be fixed (in macOS 10.13?).
Conclusion
In general, I prefer to use synchronous calls. So the possibility to use a synchronoussendIns: method is nice.Depending on your needs, the CryptoTokenKit TKSmartCard API offers you the choice between a synchronous or asynchronous version.
