2) Another question : Casascius Series 1 holograms use a 22-character variant of the minikey format, instead of 30 characters (
https://en.bitcoin.it/wiki/Mini_private_key_format). Is it also the case for version 2 Cascasius coin ? Or is it possible to proceed with a classic wallet for version 2 (because version 2 should be not with mini private key but private key)
Thanks
As far as I'm aware in order to obtain the private key associated with your Casascius coin you just need to calculate the SHA-256 hash of the string that's beneath the sticker.
As demonstration purpose only, I'll use this example[1] where we'll obtain the private key and have access to the public address of where the 5 BTC came from (Since this coin was already redeemed, I'll just use
online services to exemplify. Please do not follow my actions and instead download offline versions (if possible) and run all the process in an air-gaped device that was never connected to the internet):
- According to the pictures we are able to see that the mini private key - 22 characters - is the following:
Symc
R374ukW
S48XCfEN
rDPGaYa
gFpG
- If we use the command line in Linux we can extract the SHA-256 hash by just using the command - "$ echo -n "SymcR374ukWS48XCfENrDPGaYagFpG" | sha256sum". Another way would be to use an online service[2] - Again, only for demonstration purposes!
In either case this would be the private key associated with the previous mini private key:
c8403200856b5ec4c650950a7b265c089068b20b2219d0f8fcc063d8d34d0474
- If we go to "TP's Go Bitcoin Tests - Address" page and paste the previous result in the "0 - Private ECDSA Key" field and click Send, the last field in the website (9) will give us the corresponding Bitcoin address:
1CsBms7CvSciPeW64HWorVYcqwGVsFGoLP
If you check the transaction posted by the blogger you'll see that the previous address matches with the one that is involved in sending 5 BTC from another address of the blogger[3] (BTC value at the time was ~92 USD), thus confirming that you'll get a hold of the private key of your coin if you determine its SHA-256 string (in a safe environment) and proceed to import it to other wallets if you so desire.
[1]
https://n2liquid.wordpress.com/2013/03/09/redeeming-of-a-casascius-coin-aka-physical-bitcoin/[2]
https://emn178.github.io/online-tools/sha256.html[3]
https://blockchair.com/bitcoin/transaction/64d1f5e47428f29dc24e5776a47d6e80d12b7c70c3c11547b70c28c4d51fc891