Blockchain: the silent revolution that is reinventing trust

Blockchain is primarily a distributed ledger technology, conceived in the 1980s by cryptography researchers. However, it was with the creation of Bitcoin in 2009 that it saw its first public, open, and decentralized implementation. Often reduced to cryptocurrencies, it nevertheless refers to a much broader innovation: a shared, tamper-proof ledger that can be applied to many sectors. Bitcoin and Ethereum are two iconic applications, but blockchain goes far beyond the world of digital assets.

No, blockchain is not Bitcoin. It is the technology that made Bitcoin possible, developed well before its launch in 2009. It is also a distributed ledger that promises much broader uses, from finance to healthcare to logistics.

A large, shared, transparent, and tamper-proof ledger

Imagine a giant notebook, open to everyone, where each new line entered can never be erased. That's the basic idea behind blockchain. Unlike a traditional database managed by a bank, company, or government agency, blockchain is decentralized: each participant in the network has a copy of the ledger, identical to the others.

When a transaction is added, it must be validated collectively. Once integrated, it is sealed in a block, which is cryptographically linked to the previous one, forming an immutable chain of information. Modifying old data would be like convincing the entire network to rewrite its notebook, which is virtually impossible.

It is this mechanism that makes blockchain a "trust machine": reliability no longer comes from a central third party (bank, notary, administration), but from the system itself.

How blockchain builds trust

To be added to the chain, transactions must be validated by a consensus mechanism. These mechanisms vary depending on the blockchain and its objectives.

Proof of Work, used by Bitcoin, pits miners against each other to solve complex calculations. The first to succeed adds the block and receives a reward. This system is known for its robustness, but it consumes a huge amount of energy because it requires colossal computing power.

Proof of Stake, adopted by Ethereum since 2022, is based on "staking." Validators lock up a portion of their cryptocurrencies in order to have the right to validate a block. In the event of fraud, they lose their stake. More energy efficient, this model ensures security through financial incentives. However, the downside is increased centralization in the hands of those who hold the most ETH in staking, strengthening their power in network governance.

Once validated, the block is added to the chain, sealed by a digital fingerprint called a "hash." Each new block depends on the previous one, making falsification virtually impossible. It is this consensus mechanism that makes blockchain reliable, without the need for a bank or notary.

Other blockchains, particularly private or permissioned ones, rely on different, often much lighter consensus methods. They are used by financial institutions or companies that want to benefit from the traceability and automation offered by blockchain without suffering the energy or technical constraints of large public networks.

Much more than cryptocurrencies: finance leads the way

While Bitcoin and Ethereum have demonstrated the power of blockchain, its uses go far beyond cryptocurrencies.

In the agri-food sector, Carrefour was one of the first retailers in France to use it to trace products such as chicken and tomatoes, guaranteeing consumers transparency "from farm to fork".

In healthcare, several projects are exploring the possibility of storing medical records on blockchain so that each patient retains control over their data, while ensuring confidentiality and traceability.

In real estate, smart contracts offer a promising avenue: a sales contract could be automatically executed once the conditions are met, reducing delays and costs while enhancing legal certainty.

The finance sector has already moved on to experimentation. In 2021, the Banque de France tested the issuance and exchange of tokenized government bonds with BNP Paribas, Société Générale, and HSBC. Settlement took less than 10 seconds, compared to the usual two days.

Societe Generale Forge has already issued over €100m in bonds on blockchain, including green bonds, and has obtained approval to launch a stablecoin in euros.

In Switzerland, the Six Digital Exchange enabled the issuance of a CHF100m digital bond for Credit Suisse in 2022, while UBS launched a CHF 375m senior bond issued and settled entirely on blockchain.

In London, the London Stock Exchange Group is developing a blockchain platform dedicated to the issuance and trading of financial securities.

These experiences show that blockchain is not only disrupting cryptocurrencies, but is also beginning to transform the mechanics of financial markets.

The challenges of a silent revolution

The technology is not without its limits. Blockchains based on proof of work remain very energy-intensive. According to Digiconomist, Bitcoin alone consumes around 65 terawatt hours per year, equivalent to the electricity consumption of a country like Switzerland, between 0.3% and 0.6% of global consumption. This is a heavy burden on the environment, even though some miners manage to reuse surplus or waste energy from industry to limit waste.

Added to this constraint is technical complexity, which is slowing down large-scale adoption, and a still uncertain legal framework. Regulators will have to find answers to secure the technology's deployment.

Despite these challenges, governments, businesses, and institutions continue to invest heavily. Blockchain is now seen as an essential building block of the digital and financial economy of tomorrow.