Thanks to a lot of motivation, an engineer named Ken Shirriff proceeded to the mining of bitcoins and subsequent calculations without the help of any tool or computer. The experiment was designed to show the relative simplicity of the algorithm residing behind Bitcoin while explaining the precise operation of one of the most important aspects of bitcoin used to ensure the validation of all bitcoin transactions.
The mining of bitcoin is processed, arithmetically speaking, according to a very simple process. We first encrypt twice in a row a series of several variables: the data of bitcoin transactions to be confirmed, a purely random part, and finally, the previous successful hash (see next). All of these variables to be encrypted are called a “block”, and the result of this encryption is called a “hash”. The encryption is performed using an encryption algorithm referred to as SHA-256, encryption process that is explained in the following video made by Ken.
Only one of the 128 rounds required to obtain a “hash” are shown here. This round has been performed by Ken Shirriff in 16 minutes. However, even after obtaining a hash (which theoretically would take him 1.4 day), the chances of getting a “valid” hash (and the 25 BTC reward that come with it !) are extremely low due to the requirements on the pattern of such hash, as explained by Ken Shirriff:
In Bitcoin, a successful hash is one that starts with enough zeros. Just as it is rare to find a phone number or license plate ending in multiple zeros, it is rare to find a hash starting with multiple zeros. But Bitcoin is exponentially harder. Currently, a successful hash must start with approximately 17 zeros, so only one out of 1.4×1020 hashes will be successful
On top of that, you’ll end out with an impressive amount of differents possible hashs due to the random part of the variables that was encrypted. Therefore, it becomes extremely difficult to get the very-specific hash that will be considered as valid, as Mr Shirriff indicates:
In other words, finding a successful hash is harder than finding a particular grain of sand out of all the grains of sand on Earth
When, after centuries of human attempts or few hours of ASIC/graphic card computing, the hash’s pattern of the block of transactions is finally recognized as valid, it is then integrated into the blockchain and will serve as a basis for calculating the hash of the following transactions block.
Handmade mining of bitcoin is almost infinitely slower than using ASICS or graphics card: Ken managed to calculate 0.67 hashes per day, while the most powerful ASICS, like this one my colleague Scott Fargo reviewed, is able to calculate more than 4 500 000 000 000 hashes… per second! No wonder that the probabilities of finding the good hash leading to the discovery of a bitcoin block and it’s wonderful reward (25 BTC) is greater with the latter than with your brain!
Feel free to read the excellent blog post wrote by Ken Shirriff on his blog to learn more about the whole encryption process!
Images from Shutterstock.
Last modified (UTC): October 11, 2014 16:11