Android app-authenticator

signature.xml

<?xml version="1.0" encoding="utf-8"?>
<app-authenticator>
    <permission name="aaa">
        <package name="caller app's package name">
            <cert-digest>caller app's SHA256 hash</cert-digest>
        </package>
    </permission>
    <expected-identity>
        <package name="com.kyaracter.myapplication">
            <cert-digest>your app's SHA256 hash</cert-digest>
        </package>
    </expected-identity>
</app-authenticator>