Get public key from android keystore

android-keystore-getpublickey.kt

import java.security.KeyStore
import arrow.core.Option

const val SIGN_CERT_ALIAS = "SIGN"

fun getPublicSigningKey(): Option<PublicKey> =
    runCatching {
        val ks: KeyStore = KeyStore.getInstance("AndroidKeyStore").apply {
            load(null)
        }
        ks.getCertificate(SIGN_CERT_ALIAS).publicKey
    }.fold({
        Option.just(it)
    }, {
        Option.empty()
    })