Create certificates with cert-issuer

I’m using coinbase and your wallet and I see so many addresses that I don’t know which ones to use, nor can I see my public and private keys.
Coinbase says it only gives out the public ones when you buy the bitcoin.
And the wallet only has public keys.
So where are they or how do I get the private key?
anyone knows which bitcoin portal was used at cert-issuer.

Thank you

Can someone answer this question? Wondering about it too.

As for any blockchain transaction, you need a public/private key pair. The private should stay private and not be shared.
@magzupao What do you mean by “bitcoin portal?”

I’d start by looking into cert-issuer: GitHub - blockchain-certificates/cert-issuer: Issues Blockcerts using either the Bitcoin or Ethereum blockchain

In any case you will need to have control or at least access to your private keys. I don’t know if coinbase gives you such an access.