Blockchain and more blockchain! That’s currently a common term, almost a fad in the corporate spheres. Everybody wants something with blockchain, even if they don’t know exactly what a “blockchain” is. Something about cryptocurrencies, right? Something like a new super-techy-thingamajig, right…?
Nu exact, prietene. Deci, putem începe să afirmăm ce NU este un blockchain și pentru ce NU este:
* Blockchain isn’t a cryptocurrency.
* Blockchain isn’t an investment platform.
* Blockchain isn’t the bigger open-source platform.
* Blockchain nu poate fi un sistem distribuit.
* Blockchain nu poate fi un descentralizat sistem.
* Blockchain isn’t magical.
* Blockchain can’t solve all your problems.
* Blockchain nu poate crește câștigurile în niciun fel.
Toate clare? Apoi, putem începe a invata what a “blockchain” really is and what is its purpose in the universe.
A blockchain is…
Acest lucru nu este altceva decât un registru contabil într-o versiune criptată digital. Sounds boring? Well, it’s kind of boring, to be honest. Where’s the magic in there? Why everybody is so excited? And why this thing has something to do cu criptomonede? Să ne explicăm.
În urmă cu doisprezece ani, persoana (sau grupul de oameni) cunoscut sub numele de Satoshi Nakamoto încerca să rezolve problema dublei cheltuieli cu numerarul digital într-un mod fără încredere. O.K! Putem încetini puțin. Cheltuielile duble sunt, practic, cheltuiți aceiași bani digitali de mai multe ori (așa cum ar trebui să fie). Știi, poți copia și lipi aproape tot de pe Internet, de ce nu banii?
To avoid this kind of behavior, we’ve trusted centralized institutions, like banks and governments. Once you send an electronic bank transfer, the bank’s system discounts that money from your account. If they weren’t there, probably the people would just spend the same money several times. And that it’s like a robbery.
Asa de, Satoshi se gândea într-un sistem automat pentru a înlocui aceste instituții centralizate and make it possible to have digital cash without the double-spending problem at the same time. He/she/it grabbed then a kind of experimental cryptographic (encrypted) database created in the 70s and mixed it up with other techy-elements to create the first decentralized digital currency without a double-spending problem. And Bitcoin was born in 2009!
Această bază de date criptografică experimentală este faimosul blockchain, în ciuda faptului că nimeni nu o știa atunci. Nici măcar Satoshi: a venit numele după Bitcoin. Why not “crypto-database” or something like this, instead of “blockchain”? Well, it’s because the database is actually… a chain of blocks, as it sounds. Digital blocks.
Cum funcționează blocurile?
Every “block” is a little container of data (monetary transactions, in a cryptocurrency case), chained to all the others (pasts and futures) with something called “hashes”. These are the encrypted result from passing the data through a complex algorithm. Something like this (if we use the Algoritm SHA256):
*Initial data: You’ve transferred 1 BTC to Mike.
* Date hash: 710DAEB54021CCD83046E4FA16106E4DC10E5D617E4C28F61CE29C29CFAE823E
Every hash represents a unique identity for every transaction and every block (a group of transactions) in existence. All those identities mathematically merge later with each other, “chaining” themselves that way. So, if anybody tries to cheat, the hash of their transaction (the unique identity) will change; and if it changes, it’ll be unchained and become invalid automatically.
For example, let’s remember our initial data (You’ve transferred 1 BTC to Mike). If we change even a little character in there, the hash will radically change as well:
*Initial data: You’ve transferred 2 BTC to Mike.
* Date hash: 005002AC29AE0D1944110DB27CC73E9090F013B15207D84F2086B8646DAF549E
The transaction isn’t valid anymore and you, poor mortal, can’t deceive the blockchain system. Even if the authorities aren’t supervising. But now, let’s simulate the “merging” between transactions. Let’s say those hashes are indeed both valid and represent the identities of two different blocks. Cum se leagă între ei? Desăvârșindu-se împreună, desigur. Ca aceasta:
* Date inițiale:
* Date hash: EDFE12B5DB008F6491BA671DBE6BA25BD89BD6445B5003E9B3789605DBD24AD8
And that’s it! If you want to change something and make it valid, you must first decipher and change every block in existence. Good luck with it.
A blockchain doesn’t work alone
Despite the math, that sophisticated ledger can’t work by itself. It needs the other elements Satoshi added to it: a distributed network of nodes (and people), the aforementioned algorithm to encrypt transactions and set the rules for the validators, the transactions to spend or “coins”, and private and public cryptographic keys. Let’s check quickly one by one.
It’s not the banks or governments, but someone should verify the transactions in some way. And, for decentralized systems (like most cryptocurrencies), that’d be a distributed network conformed by a lot of people all around the world and their computers and equipment (nodes). Especially the last ones.
Lucrul este, fiecare membru al rețelei (cunoscut sub numele de miner sau validator) are o copie a întregului blockchain în hardware-ul lor, and their specialized software or mining equipment is in charge of verifying and keeping the record of every new transaction and mint new “coins”; following the mathematical rules set by the system’s algorithm. The result always should be the same for most validators, otherwise, the transaction or block will be invalid.
Un algoritm de consens
We can define an algorithm as a set of steps and methods that are built —with math— to achieve a specific result or solve a problem. There’s a lot of algorithms out there, and not all of them work to build a blockchain. They should be very complex and strong, in order to maintain high security and force the rules among validators.
Nici fiecare sistem de criptomonede sau blockchain nu folosește același algoritm. Bitcoin, de exemplu, uses SHA256 (the one we used before), but Ethereum uses Ethash and Zcash uses Equihash. They’re different mathematical functions, but the purpose is the same: encrypt the data.
Unspent transaction outputs (UTXOs)
We know the term sounds difficult, but these are the “digital coins” or transactions per se. They’re like fragments of property that work to exchange with other people. You can compare them with the bills or cents inside your physical wallet, as well.
Chei criptografice private și publice
Acestea sunt chei matematice care funcționează ca adrese pentru a trimite și primi fonduri în interiorul unui blockchain. Cheia publică este ca un număr de cont bancar: you can share it freely to receive money. The private key, on the other side, works to “sign” the transactions and verify the real owner and their intention to send the funds. In other words, a private key is like a password, and both, the private and public key, form an “account” within the cryptocurrency or the blockchain.
“Blockchain” doesn’t mean “decentralized” always
As we said at first, a blockchain may not be distributed and may not be decentralized. It’s just a cryptographic ledger, after all, and the other elements that work with it can change according to the needs of their creators.
Satoshi Nakamoto was the first person to use it with Bitcoin, dar codul sursă for this kind of ledger is open to the public. It can be copied, pasted, modified, and even sold. So, a lot of people (and enterprises) all around the world have been trying this technology for their own uses, even beyond cryptocurrencies. The banks aren’t excluded: they like using blockchains to build new payment platforms. And, as you may imagine, these aren’t decentralized, but totally controlled by the institutional network.
Sometimes, blockchains don’t work with distributed networks, just with controlled internal networks. This kind of platform needs user permissions from the creators, so, they’re called “permissioned” or private blockchains. On the other side, cryptocurrencies and platforms like Bitcoin works with decentralized networks. That makes them “permissionless” or public.