About a month ago, I posted an article on Let's Talk Bitcoin entitled "Rise of the Zombie Bitcoins." In this article, I presented a great deal of data and analysis about the state of the bitcoin blockchain in relation to long-unused addresses. In that article, I argued that the bulk of the bitcoins mined for the first two years have never been moved and, most likely, never will be. I also argued that bitcoins that have sat in particular addresses for an extremely long time with absolutely no spend activity are arguably lost forever. In total, these "zombie" bitcoins represent roughly 25% of the total number of bitcoins that have ever been produced.



This is such a huge quantity that finding out whether they should be considered part of the active economy is an important mystery to investigate. And investigate is what I have been doing. I have discovered, in the data presented in this article, strong evidence that my view may have been wrong. It turns out that someone who mined the earliest bitcoin blocks has been spending them at semi-regular intervals in relatively recent history.

Today, I will not be presenting a great deal of analysis. I offer only two simple graphs and no burndown charts. Instead, I am going to be providing absolute raw data that you, the reader, can use to become a blockchain researcher yourself. You will be able to produce your own findings, graphs, and conclusions. I encourage readers to download this data set and explore interesting ways to chart it, and then leave links to the results in the comments section.

This data set can be extremely fascinating to dig through. There are fifty old bitcoin mining reward blocks, and while most of them have never been spent, there are still some being shaken loose today. It might be pretty interesting to track down when and where this is happening and follow where they lead to.

For example, here is the address of a bitcoin public key that contained nothing but a miner's reward block, created on July 13, 2010, and made up of fifty bitcoins. Then on May 1, 2014, BOOM, the owner came along almost four years later and transferred the coins to two other addresses; one receiving forty-five bitcoins--which remains untouched--and to another that shows a lot of transaction history. So, while it is true that the vast majority of those fifty ancient bitcoin miners-reward blocks have been untouched, occasionally they do, in fact, rise from the dead. This data set provides you with a window directly into every single time this has occurred. Let the chase begin!

I would like to explain what this data set represents and how it was created. I wrote a piece of software that analyzes the entire bitcoin blockchain, since its inception, at one day intervals. For each day, I gather all of the bitcoin public-key addresses that are in active use and look for any that have had spend-transactions performed that day, relative to keys that were untouched for over two years. This data set is current as of July 26, 2014.

I start with the assumption that these untouched keys, or what I call "zombie events," are infrequent and becoming more rare all of the time. I believe the data set attached shows this to be true.

For each zombie event, I provide the following detailed information as a single line in a comma-separated-value (CSV) file that can be imported into any standard spreadsheet program.



Here is a link to a spreadsheet that shows a list of the top 148 days since April 2013 that have had significant amounts of very old bitcoins transferred. You can cross reference any of these days against the full data set to drill down into every single individual public key address and transaction that was involved. You will note that most of these zombie events refer to bitcoins that were last moved in 2011 and 2012. It is much more rare to see bitcoins that were mined during the first year of the blockchain being moved.

Date: This is the date on which the zombie event occurred.



LastDate: This is the last date that this address was used prior to this event.

PublicKey: This is the bitcoin public key address associated with the event. You can copy and paste this key into the blockchain.info website to get the entire transaction history.

Type: The type field classifies whether this public key is associated with a 50-bitcoin miner's reward, a 25-bitcoin miner's reward, or whether it is simply a normal bitcoin address not previously associated with a miner's output.

BalanceBefore: This is the balance held at this key before the zombie event occurred.

BalanceAfter: This is the balance held at this key after the zombie event occurred.

ValueChange: This is the amount of bitcoin value that was transacted during the zombie event; not necessarily all bitcoins were spent.

Age: This is how old this key was in the days since its last send transaction, prior to the event. The minimum age is two years for the data set.

ZombieScore: This is a computed value equal to the number of bitcoins previously associated with this address, multiplied by the number of days since it was last used, and squared.

In the provided data set immediately following each day that new zombie events have occurred (and zombie events do not happen every single day), a subtotal is included. The subtotals per day include the following.

TotalZombieCount: The total number of zombie events that occurred on this day.

TotalZombieValue: The total value in bitcoin addresses associated with the zombie events for the date.

TotalZombieValueChange: The total value change that occurred, which is not necessarily the same as TotalZombieValue, since only some of the bitcoins associated with each key may have been spent.

TotalZombieScore: The total zombie score for all events on this day.

Now let's take a look at some of the most significant zombie events in history. There have been around 24,000 zombie events throughout the lifetime of the bitcoin blockchain. Considering the fact that there have been millions and millions of transactions, this points out just how rare the event is when bitcoins older than two years get moved to a new address.

Take a look at these four public keys. These are public keys associated with block miner rewards of 50 BTC each that were mined over a couple of days starting January 30, 2009. This is quite literally just a few weeks after Bitcoin was started, and the keys highly likely belonged to either Satoshi, or one of his close friends. They were all spent on the same day, over five years later, on February 7, 2014. Maybe Satoshi (or Hal Finney) had some bills to pay?



Realize that this first address is a Coinbase reward from block #2400! This is the oldest address, which mined a block on January 30, 2009 (just a few weeks after Bitcoin was started), and then it was spent on February 6, 2014. Was this Satoshi?

Here are the four addresses:

15coobWGLz5rTPPLwMqDrC848g5rSqgXX1

1CgrbzKje66Pcz1egaAnhr7qEGfdk9atS2

1KiCeqdXxzTYeq1dDUi6B1265cqFwsihzm

14pDPbeBCCn4CoNKc7YZJnJSWnqfoxf1XF

Then we find that on November 15 and November 18 of 2013, someone (Satoshi?) cashed in 1,850 bitcoins over these two days, from public keys that date back to January 29, 2009! On November 18, 2013, bitcoin values were at their near all-time high of over $1,100 each. So on these two days, someone who mined blocks on January 29, 2009, in the early history of the blockchain, cashed out over a million dollars worth of these bitcoins!

On October 9, 2013, someone cashed out 200 bitcoins from the earliest blocks. Here is one of the public keys (see link) of the four he cashed out. Again, this person cashed out bitcoins mined right around January 30, 2009. It was probably the same person.

I must admit that I was surprised to find these transactions. Apparently, someone who mined Bitcoin in the earliest days has, in fact, been cashing out some of them in relatively small batches (if you can call a million dollars worth of bitcoin "small"). This person is either Satoshi himself or, more likely, one of the first handful of people who downloaded and were running the bitcoin client that could mine bitcoins easily on a CPU back then. This demonstrates that at least one person who mined bitcoins in the earliest days actively controls the keys and is making withdrawals over time, but probably not anywhere near the entire stash. This is indeed very interesting data to inspect!



Here is a spreadsheet that highlights the phases through which the bitcoins, mined during the first few weeks of the blockchain, were moved over the course of the last year.



So who are the people who would have mined bitcoins in the first few weeks? Likely they were individuals participating on the cyberphunk mailing list and responding to Satoshi's announcement of the availability of the software. Some candidates include:



Satoshi Nakamoto

Hal Finney

Ray Dilinger

Dustin D. Trammell

The bitcoin zombie event with the highest zombie score in history is a transaction on March 10, 2014 of over 111,114 bitcoins, when this public key (see link) got emptied. Considering the timing, this could have been related to the Mt. Gox fiasco. It could also belong to the Winklevoss twins, or it could have had something to do with Silk Road. Perhaps someone knows and can post it in the comments section.

On March 7, 2014, the following four public keys, three containing 40,000 bitcoins and one containing 30,000 bitcoins--for a combined total of 150,000--were all transferred out of addresses that had not been touched in 842 days, since November 16, 2011. Considering the timing, the movement of these coins was probably associated with the MtGox claim that they "found" a bunch of old bitcoins they had lost.

Here are those four addresses:

16Ls6azc76ixc9Ny7AB5ZPPq6oiEL9XwXy

12HddUDLhRP2F8JjpKYeKaDxxt5wUvx5nq

1cXNTyXj4xPGopfYZNY5xfSM1EPJJvBZV

1MyGwFAJjVtB5rGJa32M6Yh46cGirUta1K

Finally, I will include two simple charts. The first shows the number of zombie events that occur daily over time. As you can see, during periods when the bitcoin price is going up, the number of zombie events (indicating people cashing in and moving old bitcoin public keys) goes up substantially. Note that this is just a total count of events. It does not graph value.

The second shows a graph of the absolute total value in bitcoins rising from the dead on a daily basis. Note that the Y axis has been clamped at 18,000 bitcoins, since on a few days hundreds of thousands of bitcoins were moved, and they throw the graph out of scale.







References:



Here is a link to a graph showing the distribution of bitcoin balances by age.



Here is a link to a spreadsheet showing each day that a significant quantity of bitcoins rose from the dead, meaning someone transferred value older than two years.



Here is a link to the raw data as a straight ASCII CSV file, showing every single zombie event over the lifetime of the bitcoin blockchain, up until July 27, 2014.



Here is a link to a spreadsheet that shows the top 1,534 bitcoin public key addresses with a balance of greater than or equal to 1,000 bitcoins.



Finally, here are some overall blockchain statistics as of July 27, 2014:



* Total blocks: 312,869.

* Total transactions: 43,386,218.

* Total inputs: 102,938,959.

* Total outputs: 115,051,298.

* Found a total of 42,288,981 addresses that have been used.

* Found 39,120,232 addresses with a zero balance.

* Found 1,509,310 "dust" addresses (less than 1 mBTC), with a total balance of 206.78281 BTC.

* Found 1,335,814 addresses with a balance greater than 1 mBTC, but less than 1 BTC. Total balance: 116,862 BTC.

* Found 208,989 addresses with a balance greater than 1 BTC, but less than 10 BTC. Total BTC: 528,389.

* Found 99,695 addresses with a balance greater than 10 BTC, but less than 100 BTC. Total: 3,532,151 BTC.

* Found 13,407 addresses with a balance greater than 100 BTC, but less than 1,000 BTC. Total: 3,044,956 BTC.

* Found 1,435 addresses with a balance greater than 1,000 BTC, but less than 10,000 BTC. Total: 3,210,357 BTC.

* Found 97 addresses with a balance greater than 10,000 BTC, but less than 100,000 BTC. Total: 2,206,252 BTC.

* Found 2 addresses with a balance greater than 100,000 BTC. Total: 295,838 BTC.



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