Why Bitcoin does not use bcrypt for hashing?

Question

I've read that bcrypt is a hashing library that can adapt to Moore's Law and I thought that would be great for the network to adapt in a flexible manner its security to its respective growing computing power.

As far as I know, bitcoin already adapts its mining difficulty to the frequency of block generation, I wonder if some kind of similar automatic protection would be possible to do regarding the security of the hashing algorithm itself.

So, can someone with more knowledge on cryptography clarify this?

Answer 1

As far as I know, bitcoin already adapts its mining difficulty to the frequency of block generation, I wonder if some kind of similar automatic protection would be possible to do regarding the security of the hashing algorithm itself.

Changing the parameters given to bcrypt doesn't make it more secure for Bitcoin's application. Normally, bcrypt is used to hash passwords, and making the hash slower makes it harder for an attacker to use brute force to guess the password. That isn't relevant to Bitcoin, since the block header is public information. (For encrypting wallets, Bitcoin does use an iterated password hash plus a salt to derive a key.)

Of course, what Murch said is also true - even if it did provide a security boost, it would probably not be adopted.

Answer 2

Because Bitcoin didn't start out that way, and there is a lot of economic investment tied up in hardware that can only perform SHA256d hashes.