MEDIA Protocol And Blockchain Security — Part 8

4 min readMay 28, 2018

The team here at MEDIA Protocol are deeply committed to creating a more direct, transparent and secure ecosystem for content creators, publishers, and consumers through the revolutionary application of blockchain technology. We’re here to connect the worlds of marketing and technology for everyone’s benefit.

We’ve got love for both worlds, but from our own experience we know that they can sometimes feel, literally, worlds apart. So we’re committed, not just to connecting them, but to creating a common understanding between them.

This series of articles aims to explain the ins and outs of blockchain security to help everyone — the marketeers, the technologists, and the content consumers — understand the principles behind this game-changing technology.

We want to help educate by demystifying the potential applications of blockchain technology. Most importantly, we feel it’s vital to highlight and clarify the security elements of blockchain; how it safeguards data, enables open and transparent record-keeping and ensures secure digital transactions.

Strap in, and welcome to the MEDIA Protocol Blockchain Education Programme.

Part 8–49%/51% Attack

Although the fundamental basis of blockchain security lies in its distributed nature, with no centralised seat of power to attack, there is a potential threat via what’s known as a 51% attack.

Put simply, this means that one user, or group of users, supplies the computational power to more than 50% of the network nodes, thus having a certain form of overall control.

What Does The Attack Do?

The attack takes the form of interfering with the creation of new blocks in the chain.

The most affected part is in the confirmation of transactions — the part of the blockchain algorithms that run on a consensus basis. By seizing more than 50% of the locations, these malicious actors can stop payments between users by refusing to confirm the transactions.

More troubling, they can also reverse transactions, leading to double-spending. This is essentially counterfeiting, allowing the same tokens to be used more than once. Preventing this kind of counterfeiting is a key rationale behind blockchain, because it devalues the cryptocurrency.

It is practically impossible to generate new coins out of thin air, so there would be no inflation as such. But, if this type of attack succeeds, it would massively undermine confidence in that network.

Why These Attacks Are Rare

Mounting the attack would take considerable resources, at great cost. This is likely to significantly outweigh any profit that could be made from the attack.

Even larger governments would struggle to corral the computing power necessary to launch an attack of this nature, making it even less likely for private individuals.

Moves To Counter These Attacks

Ethereum is in the process of moving from the existing PoW (Proof of Work) consensus algorithm to a PoS(Proof of Stake) model, via the ‘friendly’ Casper protocol which combines both.

This moves the validation of transactions, and blocks, away from the algorithm model (where the miners supplying computational power are simply offering their resources), to one where the miners have a financial stake in accurately verifying the data.

It becomes less about contributing power, and more about the wealth backing it. So any attempts to double-spend or approve bogus transactions means that those miners will lose their financial stake.

Are We Safe?

While 51% attacks are a credible threat, the actors capable of committing them are very limited by the cost and resources required. This makes the likelihood very low.

Additionally, Ethereum and other networks are taking preventative and defensive measures as outlined above, making the blockchain more secure from these types of attacks.

For other security aspects of blockchain technology, check out the rest of our Blockchain Education Programme below.