Bitcoin: signature of block 1.018 discovered

A few weeks ago news caused a stir that someone had used a signature contained in Bitcoin block 1,018. 

In fact, block 1,018 was mined on 19 January 2009, which is only sixteen days after the first one, mined by Satoshi Nakamoto himself on 3 January that year. 

Initially, it was even imagined that that signature might belong to Nakamoto himself, but recent analysis has revealed that it might belong to Hal Finney instead. 

The discovery of Bitcoin block 1,018

It turns out that block 1,018 containing that signature is related to the first P2P transaction ever made on Bitcoin’s blockchain. 

In fact, it should be mentioned that the first blocks were mined by Satoshi and Hal Finney without any transactions other than coinbase transactions with which 50 BTC were created as a reward for the miners. After all, at that time BTC had no market, so its value was zero. 

The first P2P transaction by which BTC was sent from one public address to another occurred at block 170, on 12 January 2009, or seven days before block 1,018, and one day after Finney installed his Bitcoin client. 

Running bitcoin

— halfin (@halfin) January 11, 2009

That transaction is famous, and it is known that it was 10 BTC sent probably for testing by Satoshi Nakamoto to Hal Finney. So those 10 BTC, once sent by Nakamoto, were owned by Finney. 

Moreover, it was also discovered that the signature of block 1,018 can also be associated with other blocks mined by Finney, so it seems more than fair to assume that it is his signature. 

Hal Finney

The problem is that Finney passed away in 2014. 

Sadly, it was during 2009 that he discovered he was suffering from ALS (amyotrophic lateral sclerosis), a disease that led to his death from complications in 2014. 

Harold Thomas Finney II, known as Hal, was an American software developer, particularly of console games. He is best known, however, for being one of the earliest contributors to Bitcoin, and especially for receiving the first BTC transaction directly from Satoshi Nakamoto. 

He was also a well-known activist in the cryptographic community, and in 2004 created the first reusable Proof-of-Work system. 

It is not known whether Finney knew Nakamoto, but it is known that he in fact worked with him on that first Bitcoin software, helping Nakamoto test and fine-tune it. That is, it was no accident at all that he was the recipient of the first transaction, so much so that one could probably call him a kind of “collaborator” of Satoshi. 

In fact, actually precisely because he invented the Proof-of-Work based system many believe that Hal Finney is actually Satoshi Nakamoto, also because it is rather strange that Nakamoto disappeared into thin air as of 2011. That disappearance seems perfectly consistent with Finney’s deteriorating health condition due to ALS. Indeed, Finney’s last tweet, dated August 18, 2010, is only a few months before Satoshi Nakamoto officially and permanently abandoned the Bitcoin project. 

But if indeed the signature that popped up a few days ago was his, the hypothesis that Finney is Nakamoto weakens somewhat. 

Indeed, the immense ability to protect his identity and all his activities makes the figure of Satoshi Nakamoto hardly compatible with the discovery of his signature after his disappearance. 

Who is behind the signature of block 1,018

Even assuming we know that the signature of block 1.018 was Hal Finney’s, the question remains as to how it could be used in 2022 eight years after his death. 

Very little is known about the user who used it, thirteen years after Block 1.018. All that is known is that he owns the OneSignature account on the Bitcointalk forum, which was created the same day the signature was published. 

It is also not known how OneSignature managed to get hold of that signature. 

All indications are that he did not obtain it directly from Finney while he was still alive, and in fact obtained it only a short time ago. 

Also curious is the fact that he never mentioned that it was a signature connected to Hal Finney, perhaps because he was unaware of it. 

Although the signature appears to be authentic, some argue that it may be some sort of deception. However, this hypothesis has not been proven, so much so that it appears decidedly far-fetched at this time. 

Moreover, Bitcoin signatures cannot be forged and discovered a posteriori, so the hypothesis that someone reconstructed it should also be discarded. 

One hypothesis that seems a little less far-fetched is related to the address attached to that signature, the so-called 1NChf. The hypothesis is that this address may have been “purchased” by someone, which is something that used to happen in the past. 

It is possible that it was Finney himself who gave it out, and then who knows by what routes it reached OneSignature. In fact, it is not known what Finney did with the 1NChf address. 

Alternatively, it is also possible that it somehow ended up with his heirs, and that they in turn then decided to give it away. Indeed, if it really did pass to Finney’s heirs, one cannot even be sure that they stored it carefully and safely, so it may also have been later stolen or intercepted in some way. 

Another hypothesis, but again a long shot, is that someone may have randomly guessed that signature. To put it better, if someone is generating huge amounts of random signatures, it is not completely impossible that some of those generated might match some signatures already used by others in the past. It is extremely unlikely randomness, but not completely impossible. 

After all, the last outgoing transaction made from the address that received the 10 BTC from Satoshi in block 170 is dated 6 September 2017, so well after Finney’s death. 

Hence it is clear that someone took control of that address after his death, although it is not known who or how. 

Moreover, that address has made only two BTC transactions, one on 16 November 2010, most likely made in person by Finney himself, and one three years after his death. It has therefore been controlled by someone else for at least five years.