topic Re: iOS SDK: Creating an application fails because of appId not being 3 bytes in TapLinx SDK, TagWriter and TagInfo

iOS SDK: Creating an application fails because of appId not being 3 bytes

Wilco_G — Tue, 29 Apr 2025 13:57:32 GMT

When I select an application and create a file like this everything work as expected. Note: I created this app outside the TapLinx Library

evInstance?.selectApplication(withAppID: 0x563412) { _ in print("app selected") evInstance?.createStandardFile(withFileID: 0x01, withFileSize: 16, withCommType: CommunicationType.Plain, withReadByte: 0, withWriteByte: 0, withReadWriteByte: 0, withChangeByte: 0) { result in print("file created", result) } }

But when I try to create an application with a similar notation for the appId as the selection I get an error. I tried lots of possibilities, even 0 and 1.

com.nxp.nfclib.exceptions.UsageException: Application ID [appId] must be 3 bytes

I am stuck on creating a new application. Am I doing something in the wrong order? Also tried to manually seleting the root app and with/without authentication.

evInstance?.selectApplicationPICCP1 { _ in print("main app selected") evInstance?.authenticate(withCardKeyNo: 0, withAuthenticationType: .native, withAuthKeyType: .THREEDES, withCommandSetForAuth: .Native, withAuthkey: key) { _ in print("authenticated") evInstance?.createApplication(withAppID: 0x123456, withNumberOfBytes: 16, withAppSettings: appSettings) { result in print("Application created successfully", result) } } }

Would appreciate any help. Thanks in advance.

Re: iOS SDK: Creating an application fails because of appId not being 3 bytes

Fabian_R — Wed, 30 Apr 2025 23:45:30 GMT

Hello sir,

This is NXP customer support. Could you please clarify if you have checked our User Guide (UG10045)?

I would like to start from the top on this, to understand what could be happening.

Have you registered you application in our site and, followed the guide mentioned?

Re: iOS SDK: Creating an application fails because of appId not being 3 bytes

Wilco_G — Thu, 01 May 2025 04:49:53 GMT

Hello Fabian,

I did indeed use that guide. The app is also registered, and I successfully verified a license, also the offline version.

I have to say, though, that the guide has quite a few gaps. A sample app would have been helpful. But with the help of this forum, I’ve been able to execute basic commands. However, I’m stuck on creating an app. No matter what I use as the app ID, I keep getting this error.

Re: iOS SDK: Creating an application fails because of appId not being 3 bytes

Fabian_R — Tue, 06 May 2025 00:21:11 GMT

Could you please avoid the use of "?" as shown?

evInstance.selectApplication

and

evInstance.createStandardFile

Instead.

Is possible that the use of "?" symbol may be producing issues. In the case of selecting MIFARE applications, when the reader selects a MIFARE card is a certainty that an Application will be selected. The issue you are having is quite unexpected, I haven't been able to locate any root cause on this.

If you could share any log additional to the error received, I will appreciate it very much.

Re: iOS SDK: Creating an application fails because of appId not being 3 bytes

Wilco_G — Thu, 08 May 2025 21:24:14 GMT

I don’t see why the optional type should be a problem. If evInstance would have been nil, it would not run the method at all.

The functions “selectApplication” and “createStandardFile” are not the problem. Those functions do work. I mentioned them to indicate that the notation of the “applicationId” is accepted in these methods.

I get this error when executing “createApplication” with every possible “applicationId” I choose. The exception I get is from the method “createApplication”. It would not even return this exception if evInstance was nil.

Re: iOS SDK: Creating an application fails because of appId not being 3 bytes

Wilco_G — Thu, 08 May 2025 21:45:23 GMT

Removing the optional type did not solve the issue. Below a simplified version of my code.

self.libraryManager = TLLibraryManager.shared() let evInstance = self.libraryManager.getDESFireEV3Instance() print("\n=== Step 1: app main selecting... ===") evInstance.selectApplicationPICCP1() { isSuccess in print("=== app main selected ===") print("isSuccess: \(isSuccess)") } print("\n=== Step 2: app authenitcating... ===") evInstance.authenticate( withCardKeyNo: 0, withAuthenticationType: .native, withAuthKeyType: .THREEDES, withCommandSetForAuth: .Native, withAuthkey: key) { isSuccess in print("=== app authenticated ===") print("isSuccess: \(isSuccess)") } print("\n=== Step 3: app creating... ===") let appSettings = CreateAppSettingsModel() appSettings.appKeySettingChangable = true appSettings.authRequiredForFileManagement = false appSettings.authRequiredForFileConfiguration = false appSettings.numberOfKeySets = 2 appSettings.keyType = .AES128 appSettings.maxKeySize = 32 appSettings.masterKeyInterchangable = true evInstance.createApplication(withAppID: 0x111111, withNumberOfBytes: 160, withAppSettings: appSettings) { isSuccess in print("\n=== app created ===") print("isSuccess: \(isSuccess)") }

This results in the log below, with the exception at the bottom thrown by "createApplication".

initializeTapLinxLibrary responseString License Verified Successfully, Time to explore Taplinx Library Tag reader did become active <NFCTagReaderSession: 0x1054c7a20> isReady: true didDetect [CoreNFC.NFCTag.miFare(<NFCMiFareTag: 0x10569a0c0>)] MiFare card found Connected to tag === Step 1: app main selecting... === Command sent to card : 5A000000 [general] response.tag.type: (null) [general] response.responseData: {length = 1, bytes = 0x00} Response received : 00 === app main selected === isSuccess: true === Step 2: app authenitcating... === AuthType - Native KeyType - THREEDES KeyInfo.KeyArray - {length = 16, bytes = 0x00000000000000000000000000000000}, cardKeyNo - 0 Command sent to card : 0A00 [general] response.tag.type: (null) [general] response.responseData: {length = 9, bytes = 0xaf68e6008758263832} Response received : AF68E6008758263832 DES Session Key Before - <ComNxpNfclibDefaultimplKeyData: 0x10554c120> DES Session Key Data After - <ComNxpNfclibDefaultimplKeyData: 0x10554c120> DES Session Key Data Array After - {length = 16, bytes = 0x00000000000000000000000000000000} ------ DES, {length = 8, bytes = 0x68e6008758263832}, {length = 16, bytes = 0x00000000000000000000000000000000}, (null) ------ DES Session Key Before - <ComNxpNfclibDefaultimplKeyData: 0x10554c120> DES Session Key Data After - <ComNxpNfclibDefaultimplKeyData: 0x10554c120> DES Session Key Data Array After - {length = 16, bytes = 0x00000000000000000000000000000000} ------ DES, {length = 8, bytes = 0x85b208b0762265d7}, {length = 16, bytes = 0x00000000000000000000000000000000}, (null) ------ DES Session Key Before - <ComNxpNfclibDefaultimplKeyData: 0x10554c120> DES Session Key Data After - <ComNxpNfclibDefaultimplKeyData: 0x10554c120> DES Session Key Data Array After - {length = 16, bytes = 0x00000000000000000000000000000000} ------ DES, {length = 8, bytes = 0x8b32a8922dac433b}, {length = 16, bytes = 0x00000000000000000000000000000000}, (null) ------ Command sent to card : AFE7109DBEE0E8FD8B7E6B593689DFA4EF [general] response.tag.type: (null) [general] response.responseData: {length = 9, bytes = 0x00373c4845f783cf52} Response received : 00373C4845F783CF52 DES Session Key Before - <ComNxpNfclibDefaultimplKeyData: 0x10554c120> DES Session Key Data After - <ComNxpNfclibDefaultimplKeyData: 0x10554c120> DES Session Key Data Array After - {length = 16, bytes = 0x00000000000000000000000000000000} ------ DES, {length = 8, bytes = 0x373c4845f783cf52}, {length = 16, bytes = 0x00000000000000000000000000000000}, (null) ------ === app authenticated === isSuccess: true === Step 3: app creating... === Max Size - 32 Key Type - AES128 com.nxp.nfclib.exceptions.UsageException: Application ID [appId] must be 3 bytes === app created === isSuccess: false

Re: iOS SDK: Creating an application fails because of appId not being 3 bytes

Wilco_G — Thu, 08 May 2025 21:49:26 GMT

To confirm, removing the optional type did not solve the issue. Below a simplified version of my code.

This results in the log below, with the exception at the bottom thrown by "createApplication".

Re: iOS SDK: Creating an application fails because of appId not being 3 bytes

Wilco_G — Thu, 08 May 2025 21:54:01 GMT

I am trying to post my code and logs as requested, but for some reason it got deleted (twice). I wanted to confirm that removing the optional type does not solve the issue.

Re: iOS SDK: Creating an application fails because of appId not being 3 bytes

Fabian_R — Fri, 09 May 2025 17:55:39 GMT

Hello sir,

I am very sorry but is only possible to paste code snippets. Regarding the use of optional type, unfortunatley this is causing some issues with Taplinx.

Have you give it a try? At least for testing purposes.

I'm sorry but I haven't been able to get a reason why is the appId is producing failures.

Re: iOS SDK: Creating an application fails because of appId not being 3 bytes

Wilco_G — Fri, 09 May 2025 20:37:04 GMT

I did remove the optional type and it did not solve the issue.

Not being able to post more than two lines of code makes it hard to get real support on these kind of issues. The provided iOS guides has lots of gaps in my opinion and does not provide a complete solution.

I managed to get the basics up and running by scraping pieces from code from this forum. Some of the methods I tested do works. I just can’t get this “createApplication” to work. While it does work, when I create an application by creating my own APDU commands outside the TapLinx library. I have this feeling that this function is bugged some how.

Do you actually have a sample application that uses “createApplication” with the iOS SDK?

Re: iOS SDK: Creating an application fails because of appId not being 3 bytes

Wilco_G — Fri, 09 May 2025 21:36:38 GMT

I finally got something working, don't ask me how. There is this argument "withNumberOfBytes" and this is what the header file say about this argument: "@Param noOfBytes to allocate memory for the application to be created". I tried multiple values and made sure it is multiple of 32. I thought this was the total of amount of bytes that the whole application reserves, just like files.

evInstance.createApplication(withAppID: 0x111111, withNumberOfBytes: 512, withAppSettings: appSettings) { isSuccess in print("\n=== app created ===") print("isSuccess: \(isSuccess)") }

Every value gives me this error.

com.nxp.nfclib.exceptions.UsageException: Application ID [appId] must be 3 bytes

I got to this point that I was trying to irrational combinations. Every values of "withNumberOfBytes" gave me the above error. But when I use the value of "3" for "withNumberOfBytes" it does not give me an error, and it did created an application. I was assuming that "noOfBytes" was about the application and not about the application id.

Re: iOS SDK: Creating an application fails because of appId not being 3 bytes

Fabian_R — Tue, 13 May 2025 22:50:56 GMT

Hello Wilco,

Do you mean the @Param andNumberOfBytes:

This from TL_DESFireEV2.h file?

I will check this internally since the Android JavaDoc function does specify that the applicationID should be a 3-byte number.

Please accept our apologies for the delay this cause to your development timeline. Will let you know as soon as it is updated.

Re: iOS SDK: Creating an application fails because of appId not being 3 bytes

Shilpa_G — Tue, 20 Jan 2026 14:04:15 GMT

I am also facing same issue and same as mentioned here if we pass noOfBytes value 3 he app gets created but it will give you exception UsageException and app settings will not get apply correctly. I created app with noOfBytes value 3, but further app does not got authorised with application master key.
Let me know if this issue has proper solution other than create app using APDU commands