Finding ASIC, FPGA and GPU resistant hashing algorithms to perform a more equitable proof-of-work that would even let Smartphones participate on an equal level with computers has been a long term problem and so far there are no good solutions to it.
I myself didn’t believed there could be a solution until very recently when I got an epiphany while working with the “active authentication” feature of the passport.
Let me explain, biometric passports have been equipped with an NFC chip since their introduction 15 years ago.
Many of these passports have a feature called “active authentication” that verifies if the NFC chip has been cloned or not.
To do so the verification terminal sends a challenge to the NFC chip, a private key contained in the chip then signs the challenge and returns the signature.
It is also noteworthy that the NFC chip’s private key cannot be extracted from it, at least not easily and that it’s public key is signed by a Document Signing Certificate from the government.
So how could this help with POW?
Well, signing a challenge with a private key is similar to using sha256 or any other hashing algorithm in the sense that it will create an unpredictable and unique output for any provided input.
In this scenario passports would try to mine a block by signing it, until they find a signature that matches a certain difficulty requirement just like it is the case with the classical POW.
It is to assume that passport chips are similar enough so that they would provide a similar signing rate per second. Making it probably the most egalitarian POW mechanism that could exist.
Here is the link to the article:
https://medium.com/@janmoritz_48488/using-the-nfc-chip-of-the-passport-to-do-proof-of-work-b77e1a5343a1What do you think?
