Tap to Pay: Failed to generate key pair

[Quadriy]

Summary

Hello,

We recently implemented the Tap-to-pay functionality on our app and have received reports from some clients that they cannot connect to the tap-to-pay reader.

Code to reproduce

Check if tap-to-pay is supported before attempting to discover a tap-to-pay reader (This returns true on the devices experiencing this issue).

Terminal.getInstance().supportsReadersOfType(
    deviceType = DeviceType.TAP_TO_PAY_DEVICE,
    discoveryConfiguration = config // Discovery configuration for tap-to-pay readers.
).isSupported

Discover readers.

Terminal.getInstance().discoverReaders(
    config = config, // Config for the kind of reader we're trying to discover. Bluetooth, internet and tap-to-pay readers config.
    callback = callback, // Discovery callback.
    discoveryListener = object : DiscoveryListener {
        override fun onUpdateDiscoveredReaders(readers: List<StripeReader>) {
            // We use the results here to show the list of readers on UI.
        }
    }
)

Connect to a reader.

// Disconnect connected reader if there's one.
if (Terminal.getInstance().connectedReader != null) {
    suspendCancellableCoroutine {
        terminal.disconnectReader(callback = callback)
    }
}

// Connect to reader.
suspendCancellableCoroutine { continuation ->
    val readerCallback = object : ReaderCallback {
        override fun onFailure(e: TerminalException) {
            continuation.resumeWithException(e)
        }

        override fun onSuccess(reader: StripeReader) {
            continuation.resume(Unit)
        }
    }

    Terminal.getInstance().connectReader(
        reader = reader, // Reader selected on the UI.
        config = config, // Connection config for reader.
        connectionCallback = readerCallback
    )
}

Error

com.stripe.stripeterminal.external.models.TerminalException: Failed to generate key pair.
at com.stripe.stripeterminal.internal.common.adapter.CotsAdapter.checkAndThrowCotsError(SourceFile:657)
at com.stripe.stripeterminal.internal.common.adapter.CotsAdapter.onReaderActivated(SourceFile:487)
at com.stripe.stripeterminal.internal.common.adapter.ProxyAdapter.onReaderActivated(SourceFile:54)
at com.stripe.stripeterminal.internal.common.terminalsession.TerminalSession.activateReader$terminalsession_release(SourceFile:612)
at com.stripe.stripeterminal.internal.common.terminalsession.TerminalSession$ConnectReaderOperation.execute(SourceFile:2162)
at com.stripe.stripeterminal.internal.common.terminalsession.TerminalSession$ExternalOperation.run$terminalsession_release(SourceFile:1245)
at com.stripe.stripeterminal.internal.common.terminalsession.TerminalSession.enqueueOperation$lambda$6(SourceFile:1052)
at com.stripe.stripeterminal.internal.common.terminalsession.TerminalSession.$r8$lambda$9_FdDGpM1BaifeFRjKBBfCCLP6o(SourceFile:0)
at com.stripe.stripeterminal.internal.common.terminalsession.TerminalSession$$ExternalSyntheticLambda0.run(SourceFile:0)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:487)
at java.util.concurrent.FutureTask.run(FutureTask.java:264)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:644)
at java.lang.Thread.run(Thread.java:1012)

Android version

12, 14

Impacted devices (Android devices or readers)

Impacted Reader: Tap-to-pay (On-device)
Impacted Device: Unitech PA768

SDK version

4.0.0, 4.1.0

Other information

Not all devices are impacted (i.e. the implementation works fine on some PA768 devices).
The check for tap-to-pay support with the help of the terminal SDK returns true.
I have confirmed the device supports RSA key algorithm.

Sample video of how we have implemented discovering and connecting to readers.
https://github.com/user-attachments/assets/11ad5d4a-76ee-4cc1-bd5e-540552d1442f

[maggiewhite-stripe]

Hi @Quadriy, this issue looks similar to #486

Sometimes manufacturers will ship different versions of the same model number with and without GMS support (ex. the Sunmi v2s). Can you confirm that GMS and Google Play Services are enabled on the affected devices?

[Quadriy]

Hi @Quadriy, this issue looks similar to #486

Sometimes manufacturers will ship different versions of the same model number with and without GMS support (ex. the Sunmi v2s). Can you confirm that GMS and Google Play Services are enabled on the affected devices?

Hi @maggiewhite-stripe Yes, GMS and Google Play Services are enabled.

And running this:

GoogleApiAvailability
    .getInstance()
    .isGooglePlayServicesAvailable(this) == ConnectionResult.SUCCESS

also returns true.