So, I have been thinking this through, and I kind of decided to go crazy all the way now.

We all know that every BTC address has its own unique private key.

And so for extra security, the private key is generated randomly, from a completely random set of 64 HEX chars.

But this is where I'm lost. What exactly is "randomly"? I have searched and found over 4 or 5 essays about types of private key generation. And in many places I cannot understand some few nuances.

Specifically, any 256-bit number from 0x1 to 0xFFFF FFFF FFFF FFFF FFFF FFFF FFFF FFFE BAAE DCE6 AF48 A03B BFD2 5E8C D036 4140 is a valid private key.

Why 0xFFFF FFFF FFFF FFFF FFFF FFFF FFFF FFFE BAAE DCE6 AF48 A03B BFD2 5E8C D036 4140? Why not 0xFFFF FFFF FFFF FFFF FFFF FFFF FFFF FFFE FFFF FFFF FFFF FFFF FFFF FFFF FFFF FFFF?

And when you're reading about Private keys you get to the "

Elliptic Curve Digital Signature Algorithm"

And again, " A private key is essentially a randomly generated number."

What exactly is randomly generated? Is it as simple as rand() % 0xFFFF FFFF FFFF FFFF FFFF FFFF FFFF FFFE BAAE DCE6 AF48 A03B BFD2 5E8C D036 4140 ? Where it takes any random number from 1 to 1.157920892373162e+77? and then hash them to SHA-256 twice? or is it more complicated than that?

Wouldn't that lead to some wallets being completely easy to crack as their initial code being only a 6 char or 18 char number? It is random after all, don't go tell me about how low the chances are, I know they're almost infinite, but they're still a chance.

Bottom line is, I want a clear idea of how "random" in generation bitcoin private keys is? Thanks for reading.