Suggestions for other methods to authenticate?
- How do you know in a Casascius coin the private key is not compromised? I hope I did not ask a stupid question
OP: Thanks for creating the topic.
1st, check the blockchain to see if coin/address has been redeemed
2nd, check the hologram on the coin itself. It has anti-tamper measures that can be seen if someone tries to remove/lift.
Might be some other things you could do, but if remember: Not your keys, not your bitcoin.
While it might be nice to own these or even "store" your bitcoin, the ultimate security comes from controlling your own keys