Monday, October 23, 2017

Quantum Computing and Building Resistance into Proof of Stake

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While both mining via Proof of Work (POW) and staking are two of the most popular ways to perform work to earn income, cryptocurrencies are also susceptible to advances in computing, which could undercut the value of the coins by making them much easier and less expensive to mine. The dawn of quantum computers is upon us. And while this causes many to fear the loss of income potential, the truth is that an increase in difficulty to mine or stake is factored into the underlying algorithms in blockchain systems which have adjusted accordingly from central processing units to graphics processing units. From field-programmable gate array to application-specific integrated circuits.

 

The real threat quantum computing has for cryptocurrency work systems is in attacking the public-key cryptography.

Quantum Computing and Bitcoin

Satoshi Nakamoto created Bitcoin on the unspent transaction output (UTXO) model. In basic terms, think of all bitcoins in your wallet as change. When making a payment, this change is combined and sent. Once bitcoin is spent, the public keys of that address are broadcast to the entire network so that they can verify that you signed the coins over to a new address. Quantum computers have the ability to reverse your private key from your public key, so address reuse becomes a problem.

 

With the UTXO model, any change you have from a transaction will go to a newly generated address. All addresses which have never been spent are safe from a public-key attack because the key has not been broadcast. This does not change the fact that many basic users reuse addresses for convenience and many work protocols like POS reuse addresses as well.

Vulnerabilities in POS

To generate passive income by POS, this process is called staking. During staking, some of your coins are locked and unavailable to spend. Similar to a savings account in a bank, these coins are reserved by the network for a short period of time. In return for borrowing these coins the owner receives interest (coins) just like banks pay customers interest. POS coin supplies are inflationary at a variety of yearly rates; providing stakers better interest than local banks or credit unions.

 

In most cases, your coins need to be available to the network (online) in order to be staked. However, if you lack guaranteed internet connectivity or just prefer not to keep your wallet online all the time in order to mitigate potential exposure to security risks, you are at a disadvantage because you can’t earn passive income on your coins while they are offline.

 

While staking is considerably less energy intensive, POW is still considered by many to be superior to POS. One of the chief arguments for that position is a security flaw in staking systems — POS gives away your public key when you stake.

This argument has merit because in most cases coins are stored in a small amount of addresses, mostly one, and that address is unlocked (unencrypted) for staking. The public key of these unlocked staking addresses is regularly being broadcast to the network.

One project building resistance to quantum computing is Particl, the open-source privacy framework built on blockchain technology. Here’s a look at how that project leverages innovations like cold staking, multi-signatures and HD wallets to improve POS security, maximize income-generation  and provide secure, private, flexible spending options for owners of its token, PART.

Cold Staking

In its most basic terms, cold staking keeps your spend public key and private key private.


While you still need to be online to generate stakes, cold staking leverages multi-signature addresses so you can stake from multiple computers. A person earning passive income on a network with cold staking, like Particl’s, can set up a dedicated stake-only machine while simultaneously spending those coins around the world on any mobile HD wallet like Ledger or Particl’s own Copay App.

 

In terms of quantum resistance, this makes reversing private keys to public keys nearly impossible. For beginners, the stake-only machine is broadcasting a public key that is different than the mobile wallet key. In order to steal coins, both private keys would need to be known when using multi-signature. The more computers broadcasting stakes and spending stakes the greater the resistance becomes.

 

On November 10, the Particl network will have a planned hard fork to activate cold staking on the main blockchain. The team has been community testing this new feature on its test network since the beginning of August.

Summary

Although most cryptocurrencies lack cold staking support, Particl is not the only platform to support it. A few others, such as BlueCoin and BlackHalo, also enable cold staking.


If you’re seeking to build a reliable passive income stream over the long-term using cryptocurrency, a feature like quantum resistance is important. If the past half-century is any indication, computers will always grow more and more powerful. A sudden advance in computing technology could practically wipe out the value of coins that lack quantum resistance.

 

As the cryptocurrency world evolves and grows more complex, generating income reliably using cryptocurrency is also becoming more challenging. Features like cold staking and quantum resistance provide income-generation benefits and guarantees that are now available from core cryptocurrency platforms like Particl.

The post Quantum Computing and Building Resistance into Proof of Stake appeared first on Bitcoin Magazine.



from Bitcoin Magazine