Uploading apk built on cordova gave error- 'Your apk signed with different certificate as pervious apk.'

The app wasn't built originally by me, so I don't understand keystore, alias and password. But I was given a key that kind of looks like this. I assumed it was one of the three.

oi39.ElqNBBjc72BiKRprL9r4IpVKvtKxT-IioEpVlpW9FnoeKd8Do3jdoce93_komdho30cn_jd003j......Illsiiwk93si0s-D3g

Is it possible to update the app with this, and how would I approach it?