Bitcoin and blockchain security
The Bitcoin protocol states that in this case, the block that has been worked on more will be incorporated into the chain and the other discarded. In that case, it effectively controls the ledger. If it is malicious, it can spend bitcoins twice, by deleting transactions so they are never incorporated into the blockchain. The other 49 percent of miners are none the wiser because they have no oversight of the mining process.
That creates an opportunity for a malicious owner of a quantum computer put to work as a Bitcoin miner. If this computational power breaks the 50 percent threshold, it can do what it likes. Their conclusion will be a relief to Bitcoin miners the world over. Aggarwal and co say that most mining is done by application-specific integrated circuits ASICs made by companies such as Nvidia. But there is a different threat that is much more worrying.
Bitcoin has another cryptographic security feature to ensure that only the owner of a Bitcoin can spend it. This is based on the same mathematics used for public-key encryption schemes. The idea is that the owner generates two numbers—a private key that is secret and a public key that is published. The public key can be easily generated from the private key, but not vice versa. A signature can be used to verify that the owner holds the private key, without revealing the private key, using a technique known as an elliptic curve signature scheme.
In this way, the receiver can verify that the owner possesses the private key and therefore has the right to spend the Bitcoin. The only way to cheat this system is to calculate the private key using the public key, which is extremely hard with conventional computers.
But with a quantum computer, it is easy. Indeed, quantum computers pose a similar risk to all encryption schemes that use a similar technology, which includes many common forms of encryption. There are public-key schemes that are resistant to attack by quantum computers. So it is conceivable that the Bitcoin protocols could be revised to make the system safer. But there are no plans to do that now. Bitcoin is no stranger to controversy.
It has weathered various storms over its security. But that is no guarantee that it will cope well in the future.
One thing is sure: A new prototype gets at how—and why—manufacturers and product designers might benefit from a blockchain. Everything included in Insider Basic, plus the digital magazine, extensive archive, ad-free web experience, and discounts to partner offerings and MIT Technology Review events.
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Business Impact Quantum Computers Pose Imminent Threat to Bitcoin Security The massive calculating power of quantum computers will be able to break Bitcoin security within 10 years, say security experts. This summer, you may be able to hail a self-driving car in Texas.
US will label GMO foods with smiley faces and sunshine. How can we be sure AI will behave? Perhaps by watching it argue with itself. A criminal gang used a swarm of drones to disrupt an FBI raid. Read unlimited articles today. Become an Insider Already an Insider? Paying with Your Face: At present, few Bitcoin blockchain transactions contain extra data — only 1. Nonetheless, the presence of even a small amount illegal or objectionable content could pose problems for participants.
The researchers acknowledge that there haven't yet been definitive court rulings on this specific issue but insist "However, considering legal texts we anticipate a high potential for illegal blockchain content to jeopardize blockchain-based system such as Bitcoin in the future," they state.
CryptoGraffiti anticipates the risk posed by objectionable content in policy statement for those who attempting to post data to the Bitcoin blockchain: In case of abuse we may report your IP address to the police. That's not necessarily much of a deterrent.
While adding something like "Remember Tiananmen Square" or a picture of the Dalai Lama to the blockchain wouldn't be an issue in the US, it could cause Chinese authorities to take steps to prevent that content from being redistributed through Bitcoin nodes in China.
Adrian Colyer, a partner with VC firm Accel in London who wrote a blog post about the paper, suggests the ability to add arbitrary data to Bitcoin's blockchain could be used as a pretense for governments to harass political foes operating Bitcoin nodes.
Matzutt confirmed that an individual could "poison" the blockchain by inserting a politically contentious image. Matzutt echoed Harding's sentiments. He pointed to an upcoming paper , to be presented in April, that deals with the issue. Matzutt argues that until countermeasures such as fees are formalized, the Bitcoin community could deploy a quick fix such as rejecting "suspicious" transactions. Minds Mastering Machines - Call for papers now open. The Register - Independent news and views for the tech community.
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