the risk is minimal, in simplifying the task for a quantum machine to compute a private key having a signature result
It should be OK, but I wouldn't do it.
DIP3 was designed to remove trust.
The commands to register a node should be run you.
ie protx register_prepare .. signmessage ... protx...
I do not want to trust, I want to know that the by signature of the message can not access to the 1000 coins, it can only be done by signing the transaction. They're not asking to sign a transaction, they're asking to sign a message (give them only the signature of the message)
Hello, operator allnodes.com requires me to sign a his message to start a masternode, can he to steal my coins after? Wallet issues a warning that it is not recommended to sign obscure messages, this can take advantage to scam
signmessage XwDnps*******************UArEDS...
Core wallet is not a cold wallet because the private key gets on the machine which is in the network. You can use Electrum on a machine that is not online to send a transaction and sign a message
docs.electrum.org/en/latest/coldstorage.html