# A strong man who challenges Bitcoin mining with mental arithmetic with paper and pencil appears

ByVoyageAnatolia.blogspot.com

Virtual currency "**Bitcoin (bit coin)**You can create new bit coins by calculating using PC or specialized hardware. The act of unearthing this bit coin is called "mining", which requires a high spec machine and a huge amount of time, but challenges its mining only with "paper", "pencil" and "brain" A strong man appeared.

**Ken Shirriff's blog: Mining Bitcoin with pencil and paper: 0.67 hashes per day**

**http://www.righto.com/2014/09/mining-bitcoin-with-pencil-and-paper.html**

In bit coin settlement, all bit coin exchanges (transactions) are managed in units of "blocks" and are described in "books" called "block chains" that connect this block and blocks. In mining, a value called "hash value" is calculated to connect the block and the block, and the validity and fairness of the transaction are secured by this calculation. And the energy required to calculate the hash value is provided from the mining person (minor), and it is operated by the mechanism that a bit coin to be newly "discovered" is given as a consideration that provided minor energy .

**Mining is beyond the dimension that an amateur can already hand out**As competition to raise the performance of the machine like the arms race, as a result, a high spec machine equipped with mining dedicated chips is essential, Mr. Ken Schulff wrote "paper" and "pencil" and "brain Using a human-powered hash value calculation challenge**Publish on blog**doing.

Bitcoins for mining**SHA-256**We adopt the algorithm called SHA - 256, which makes security more robust by using double. However, SHA - 256 's algorithm itself is a very simple mechanism, according to Mr. Schriff, it can be mined manually.

This is a schematic diagram showing how the hash value is calculated by mining. (Here, "17975b ......") of the previous block "previous block hash" and information "Merkle root" (here, "8e97295a ......") and a random variable called "nonce" In this case, "48750833") is assigned to the hash function and calculated, and the hash value "Block hash (block hash)" is calculated. Changing the nonce will change the block hash, so it is mining to calculate it by randomly changing the variable nonce.

Block hash means that when a "0" is a consecutive number, "correct answer" is present, and now a block hash with 17 consecutive zeros is calculated, a new bit coin will clearly appear. The block hash with 17 consecutive 0's is calculated once at 1 垓 (10's 20th power).

In order to calculate the hash value by manual calculation, Mr. Schriff created a table as shown below. You can calculate the hash value by inserting numbers and letters in this square.

The time taken for the first calculation process was 16 minutes 45 seconds, and the state of the calculation is contained in the following movie.

**Mining Bitcoin with pencil and paper - YouTube**

Mr. Schriff actually tried to do the ming with paper and pencil, but the work was easier than imagined. Furthermore, considering that the mining speed by Mr. Schriff is 0.67 hash / day, considering that the computing speed of the mainstream mining machine is the Nagoya (10 16 16) hash, it is obviously not usable for bit coin excavation level. However, "I could understand exactly what kind of mining is being done by actually performing mining work by manual calculation," Mr. Schriff said.

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