2
Suppose someone has single private key, and from that private key he made a public key for Bitcoin, Ethereum, Dogecoin, etc. - is it possible to figure out the private key having those multiple public keys?
2
Suppose someone has single private key, and from that private key he made a public key for Bitcoin, Ethereum, Dogecoin, etc. - is it possible to figure out the private key having those multiple public keys?
1
It depends on how many times that private key has been used and whether the attacker has access to a side channel. Practically speaking if the attacker does not have access to a side channel and does not know a vulnerability in the secp256k1 curve (there are no known ones), then no, it's not practically possible to figure out the private key.