ZmnSCPxj » Bitcoin » On Unstoppability of Softforks


It was brought to my attention, that a certain individual whose name shall not disgrace this page, wrote in an article whose address shall also not disgrace this page, regarding the deprecation of P2SH and the complete prevention of softforks in the altcoin that individual was making.

This was quite interesting to me.

Could Softforks be Prevented? ...

...was the subject of a thread on bitcoin-dev last year.

The original poster identified, that anyone-can-spend outputs were the point, where softforks can be hooked.

After some explanation, I pointed out the simple fact: that P2PKH is sufficient to create anyone-can-spend. Indeed, something as simple as paying to a singlesig pubkey is enough to create an anyone-can-spend output.

The key insight is that a payment to a public key is spendable, by all who know the private key. If the private key is published to everyone, then anyone can spend the output.

The obvious conclusion is that softforks are simply not possible to prevent. The most basic blockchain, requires at least some kind of public-private key cryptography. And the publication of a specific private key, is sufficient to allow anyone-can-spend.


While amusing, this points to a simple fact: that softforks are simply not preventable. Cryptocurrencies cannot be created which cannot be softforked, without losing simple security.