By checking the chainwork, which exhibits the entire hashes which can be anticipated to be calculated. As of block 765365, it is 00000000000000000000000000000000000000003a8a576dba35308e77dc8446
.
In decimal, that is 18,117,375,202,741,628,848,220,608,424.
Satoshi used P2PK again in 2009, so there is just one legitimate Bitcoin personal key that may signal for the corresponded rewarded public key. Due to this fact, you may have 1 in 2^256 – 2^32 – 977, which is far bigger quantity.
In decimal, it is 115,792,089,237,316,195,423,570,985,008,687,907,853,269,984,665,640,564,039,457,584,007,908,834,671,663.
However, to be truthful, calculating SHA256d hashes of block headers, and brute forcing personal keys aren’t the identical computational processes, economically talking.