Integrating Passkeys signCount 0

Question

I'm trying to implement passkey into my app. I am wondering if ASAuthorizationPublicKeyCredentialAssertion.rawAuthenticatorData supports signCount. It seems the value is always 0. Thank you!

Answer 1

For security keys, this will contain whatever signCount the security key itself provided. For passkeys, signCount is not supported and will always be 0. That field isn't meaningful for a synced credential that can be used at any time from multiple devices. For easier implementation I would use passkeys.com or read more at apple.docs

Answer 2

signCount will always be zero for multi-device credentials (passkeys).