What is secretKeyName used by CryptographyManager?

Question

I integrated Biometrics authentication follow this guideline (https://developer.android.com/codelabs/biometric-login#2). I have a question about the secretKeyName.

private fun showBiometricPromptForEncryption() {
   val canAuthenticate = BiometricManager.from(applicationContext).canAuthenticate()
   if (canAuthenticate == BiometricManager.BIOMETRIC_SUCCESS) {
       val secretKeyName = "biometric_sample_encryption_key"
       cryptographyManager = CryptographyManager()
       val cipher = cryptographyManager.getInitializedCipherForEncryption(secretKeyName)
       val biometricPrompt =
           BiometricPromptUtils.createBiometricPrompt(this, ::encryptAndStoreServerToken)
       val promptInfo = BiometricPromptUtils.createPromptInfo(this)
       biometricPrompt.authenticate(promptInfo, BiometricPrompt.CryptoObject(cipher))
   }
}


private fun showBiometricPromptForDecryption() {
   ciphertextWrapper?.let { textWrapper ->
       val secretKeyName = getString(R.string.secret_key_name)
       val cipher = cryptographyManager.getInitializedCipherForDecryption(
           secretKeyName, textWrapper.initializationVector
       )
       biometricPrompt =
           BiometricPromptUtils.createBiometricPrompt(
               this,
               ::decryptServerTokenFromStorage
           )
       val promptInfo = BiometricPromptUtils.createPromptInfo(this)
       biometricPrompt.authenticate(promptInfo, BiometricPrompt.CryptoObject(cipher))
   }
}

My question is what is secretKeyName? Is the secretKeyName in prompt for encryption same as prompt for decryption? How do I get this value?

Thanks!!