Android vulnerability hits Bitcoin apps and more

When a random number is not so random, security pays the price

Android users of Bitcoin are being advised to upgrade their apps and re-secure their wallets after the discovering of a weakness in a component of the operating system responsible for generating secure random numbers. The weakness also affects some secure communication networks, and renders users vulnerable to theft of their digital currency.

The weakness lies with the Android implementation of a piece of code which is supposed to spit out purely random numbers. Instead of working as it should, the numbers it produces aren’t as random as they seem. These numbers are used by Bitcoin users as the public and private keys in the series of mathematical problems which makes up the “blockchain”, the record of transactions. If they are slightly predictable, then as a result, it is theoretically possible to work out someone’s private key from the public signatures they post, and steal money contained in the wallet.

The vulnerability was highlighted by developer Mike Hearn, who created the Bitcoin Wallet app. That app has since been updated, as have Mycelium Wallet and, two other popular wallet apps for Android., a key website for the decentralised development community, advises users to “rotate” their keys. “This involves generating a new address with a repaired random number generator and then sending all the money in your wallet back to yourself”, they write. “Once your wallet is rotated, you will need to contact anyone who has stored addresses generated by your phone and give them a new one.”

However, the weakness in the random number generator has the potential to affect more than just bitcoin apps. Any app which relies on the generator for security is at risk, particularly if the programme requires a public and a private key. The nature of the flaw makes it overly easy to determine a private key if given a public key generated around the same time; as a result, any app which uses a form of public key cryptography, where the security of the encrypted content relies on the public and private keys being unrelated, is at risk if those keys were generated using the faulty generator.

In practice, though, the Bitcoin community is at the most risk here. It's one of the few situations where a public key is very public indeed, and the rewards for cracking it are so immediate that if people can try, they will. But it's hardly a mortal wound; the apps can be updated, and wallets resecured. If Bitcoin is really in danger, it comes from a source which many advocates of the digital money are celebrating. Earlier this month, a Texas court officially declared Bitcoin a "currency" in order to take action against a man accused of running a Bitcoin Ponzi scheme. What sounds like much-needed mainstream recognition is actually a double-edged sword, though. As a currency, it is now fair game for regulators. And sure enough, the New York Department of Financial Services is looking into the "Wild West for narcotraffickers and other criminals". Bitcoin will shortly need to grow up or shut up, it seems.


Alex Hern is a technology reporter for the Guardian. He was formerly staff writer at the New Statesman. You should follow Alex on Twitter.

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The future of policing is still at risk even after George Osborne's U-Turn

The police have avoided the worst, but crime is changing and they cannot stand still. 

We will have to wait for the unofficial briefings and the ministerial memoirs to understand what role the tragic events in Paris had on the Chancellor’s decision to sustain the police budget in cash terms and increase it overall by the end of the parliament.  Higher projected tax revenues gave the Chancellor a surprising degree of fiscal flexibility, but the atrocities in Paris certainly pushed questions of policing and security to the top of the political agenda. For a police service expecting anything from a 20 to a 30 per cent cut in funding, fears reinforced by the apparent hard line the Chancellor took over the weekend, this reprieve is an almighty relief.  

So, what was announced?  The overall police budget will be protected in real terms (£900 million more in cash terms) up to 2019/20 with the following important caveats.  First, central government grant to forces will be reduced in cash terms by 2019/20, but forces will be able to bid into a new transformation fund designed to finance moves such as greater collaboration between forces.  In other words there is a cash frozen budget (given important assumptions about council tax) eaten away by inflation and therefore requiring further efficiencies and service redesign.

Second, the flat cash budget for forces assumes increases in the police element of the council tax. Here, there is an interesting new flexibility for Police and Crime Commissioners.  One interpretation is that instead of precept increases being capped at 2%, they will be capped at £12 million, although we need further detail to be certain.  This may mean that forces which currently raise relatively small cash amounts from their precept will be able to raise considerably more if Police and Crime Commissioners have the courage to put up taxes.  

With those caveats, however, this is clearly a much better deal for policing than most commentators (myself included) predicted.  There will be less pressure to reduce officer numbers. Neighbourhood policing, previously under real threat, is likely to remain an important component of the policing model in England and Wales.  This is good news.

However, the police service should not use this financial reprieve as an excuse to duck important reforms.  The reforms that the police have already planned should continue, with any savings reinvested in an improved and more effective service.

It would be a retrograde step for candidates in the 2016 PCC elections to start pledging (as I am certain many will) to ‘protect officer numbers’.  We still need to rebalance the police workforce.   We need more staff with the kind of digital skills required to tackle cybercrime.  We need more crime analysts to help deploy police resources more effectively.  Blanket commitments to maintain officer numbers will get in the way of important reforms.

The argument for inter-force collaboration and, indeed, force mergers does not go away. The new top sliced transformation fund is designed in part to facilitate collaboration, but the fact remains that a 43 force structure no longer makes sense in operational or financial terms.

The police still have to adapt to a changing world. Falling levels of traditional crime and the explosion in online crime, particularly fraud and hacking, means we need an entirely different kind of police service.  Many of the pressures the police experience from non-crime demand will not go away. Big cuts to local government funding and the wider criminal justice system mean we need to reorganise the public service frontline to deal with problems such as high reoffending rates, child safeguarding and rising levels of mental illness.

Before yesterday I thought policing faced an existential moment and I stand by that. While the service has now secured significant financial breathing space, it still needs to adapt to an increasingly complex world. 

Rick Muir is director of the Police Foundation