I have a computer but it is not secured. I have an idea, maybe I will have to import my wallet in the desktop electrum wallet, after signing I will uninstall the wallet.
Even better: instead of importing your existing wallet, create a new one on your desktop and use it only for signing. Write down the seed phrase, and write "used for staked address on Bitcointalk" on the paper.
Importing funded wallets always increases the risk.
Im writing this post now just to let all know that my old Bitcoin address " 39oMwW6C9afRMAX8J3iDdDg12CN5V54dmw " is not longer active.
My new Bitcoin address is now " bc1qt7a65enqm7rn66vj7v78wx5jr5f269tl99en9clt5wae9cfnc0msjskm22 " and its shown in my Profil now also.
To be thorough: can you sign a message from 39oMwW6C9afRMAX8J3iDdDg12CN5V54dmw, and post a link to where you first posted it? I guess you can't: it looks like the address belongs to an exchange. Considering the length of your new address, it looks like multisig and may belong to an exchange too. That's useless for staking, as you can't use it to prove ownership.Also: using only one address (with 351 transactions) is terrible for privacy, and inconvenient to distinguish payments.
Update: I should have read the next page first:
There is no pk for the old and for the new address because its a Bitcoin address from Bitstamp if you exactly wanted to know.
I dont use or write my private Bitcoin address anywhere because of security reasons.
You don't need to use a funded Bitcoin address for staking, just dedicate a new empty address to it.