In this section of the lesson, we will deal with the three main cryptographic primitives on which Bitcoin is based: the hash algorithms, the digital signature algorithm, the Merkle trees, and the hashcash algorithm. Cryptographic hash function A cryptographic hash function (or summary function) is an algorithm that takes as input any data of any length (the message ) and returns a string of fixed-length bits (the hash ). The main characteristics of an ideal cryptographic hash function are the following: Efficiency in computing. You must provide a quick calculation of the hash from an input message. Preimage resistance. It must be computationally very difficult to generate the message from which the summary has been derived. Resistance to the second preimagen . It must be computationally very difficult, given a message, to get a second message that generates the same hash. Resistance to the collision . It must be computationally very difficult to generate two dif...
Bitcoin is a decentralized digital currency that operates over a P2P network (Peer-to-Peer) that is based on the use of cryptographic tools to control security and privacy in the creation, use, and transfer of electronic money. In the same way as any common currency, Bitcoin has an abbreviation to identify it in the markets: BTC. Throughout the lesson, we will take the proper name Bitcoin to refer to the network and the protocol, while we will choose the name bitcoin or BTC to call the currencies with which the transactions are made. Bitcoin was initially created by Satoshi Nakamoto from an article published in 2008 and in which the Bitcoin protocol [ bitcoinPaper ] is described. The article explains the initial concepts of Bitcoin and proposes an outline of what is currently Bitcoin: an electronic payment system using the electronic currency. To date, and after numerous speculations nobody knows with certainty who or who are Satoshi Nakamoto since the only thing that is known i...