One of Hal Finney's lost contributions to Bitcoin Core to be 'resurrected'

In a February 8, 2011 post on Bitcointalk, Finney said that reading a book titled "Guide to Elliptic Curve Cryptography" by Hankerson, Menezes, and Vanstone, gave him an idea of how to speed up signature verification by 25%. In the following post from the same day, Finney announced that he had already written "Test code" and uploaded it to the Github repository.

There was a problem with Finney's proposal - his method had already been patented by someone else.

"Method for Accelerating Cryptographic Operation on Elliptic Curves" received a patent on September 19, 2006 - likely at a time when Satoshi Nakamoto was already busy at work on Bitcoin.

Finney's 2013 proposal was implemented with the release of the libsecp256k1 library, but was never enabled due to existing legal concerns.

February 2011 seems to be the time when Finney was most focused on optimizing Bitcoin's signature verification.

In a post from February 7, 2011, Finney said he was looking at "Batch signature verification", which he believed might speed up the process by a factor of four.

The idea behind it was that instead of verifying signatures one by one, to verify them block-wise: hundreds or even thousands at a time.

"The benefit of batch+GLV over just batch is less than single+GLV over just single. And for very large numbers, the benefit tends to a ratio 1. But at least up to 1000s of signatures, it is still an advantage."

It has been implemented for Schnorr signatures where it affords two-fold gains in speed.

"Later this year/next year Schnorr signatures released including activation and then batch verification speed up also becomes available."