Bitcoin offers privacy -- as long as you don't cash out or spend it

Most users do not use sophisticated methods that would more deeply mask their transactions

On the surface, Bitcoin seems to be a great way to hide cash. Actually, it's a terrible way to launder money.

That's the conclusion of a new academic study that analyzed Bitcoin's blockchain, or the public ledger that records bitcoin transactions. The ledger shows how bitcoins move from one person to another, represented by 34-character alphanumeric addresses.

It's a sea of numbers without names. But researchers from the University of California at San Diego and George Mason University found it is a lot harder to convert bitcoins to cash -- or spend the bitcoins with a service -- and stay anonymous due to the ledger.

Most bitcoin users interact with a service to buy or sell the virtual currency. These days, most of those services want to know exactly who they're dealing with, especially as regulators around the world take an increasing interest in bitcoin.

Using special algorithms, the researchers were able to associate large numbers of seemingly anonymous bitcoins addresses with certain major services such as exchanges and payment processors, said Sarah Meiklejohn, a doctoral candidate in computer science at UC San Diego, who assisted in the research.

By analyzing those transactions, they found it is possible to somewhat deanonymize bitcoin users, opening up avenues through which investigators could reveal the people behind them.

For example, they linked more than 500,000 Bitcoin addresses with Mt. Gox, a popular exchange in Japan where users buy and sell bitcoins. Mt. Gox requires identification from its users, often including a scan of their passport. It wouldn't make sense for a hacker to cash out a large number of bitcoins there.

"We haven't uncovered the identity of the thief, but we've paved the way for law enforcement or an agency with subpoena power to do exactly that," Meiklejohn said.

The researchers analyzed details from bitcoin thefts. While there are sophisticated methods that can be used to cloud whether a bitcoin is indeed still held by a thief, many thieves became lazy after initially moving stolen funds around, Meiklejohn said.

"Maybe thieves and other criminals in the future are going to become a lot more sophisticated, but I think so far, people have not been particularly careful," she said.

Many bitcoin thefts have remained frozen: The victim saw what address their funds went to, but the funds have never moved, perhaps because the hacker is still mulling how to convert the virtual currency to cash or goods without being noticed.

Average bitcoin users appear to be unaware at how quickly their bitcoin spending could be linked back to them. The Silk Road, an online marketplace of mostly illicit goods, only accepts bitcoin.

"We saw a lot of people deposit into Silk Road directly from their Mt. Gox address," Meiklejohn said. In those cases, law enforcement would have minimal work to obtain the name of a user if they presented a legal order to Mt. Gox.

Money laundering is not impossible, but it is not particularly attractive with bitcoin. "It seems like an offshore account at this point would be a lot easier," she said.

Still, as long as bitcoin users are willing to take certain cumbersome steps, such as generating new bitcoin addresses for every transaction, staying off the exchanges and using other evasion techniques such as repeatedly forwarding funds, Bitcoin retains its privacy strengths.

"I do think inherently Bitcoin can provide you with a huge amount of anonymity, but the argument here is you have to work for it," Meiklejohn said. But most patterns of bitcoin use "indicate most users are falling short."

Meiklejohn co-authored the paper with Marjori Pomarole, Grant Jordan, Kirill Levchenko, Damon McCoy, Geoffrey M. Voelker and Stefan Savage.

Send news tips and comments to jeremy_kirk@idg.com. Follow me on Twitter: @jeremy_kirk

Join the Good Gear Guide newsletter!

Error: Please check your email address.

Tags Internet-based applications and servicesMt. GoxsecurityUniversity of CaliforniaSan DiegoGeorge Mason Universityinternet

Our Back to Business guide highlights the best products for you to boost your productivity at home, on the road, at the office, or in the classroom.

Keep up with the latest tech news, reviews and previews by subscribing to the Good Gear Guide newsletter.

Jeremy Kirk

IDG News Service
Show Comments

Essentials

Microsoft L5V-00027 Sculpt Ergonomic Keyboard Desktop

Learn more >

Lexar® JumpDrive® S57 USB 3.0 flash drive

Learn more >

Mobile

Lexar® JumpDrive® S45 USB 3.0 flash drive 

Learn more >

Exec

Audio-Technica ATH-ANC70 Noise Cancelling Headphones

Learn more >

Lexar® Professional 1800x microSDHC™/microSDXC™ UHS-II cards 

Learn more >

HD Pan/Tilt Wi-Fi Camera with Night Vision NC450

Learn more >

Lexar® JumpDrive® C20c USB Type-C flash drive 

Learn more >

Budget

Back To Business Guide

Click for more ›

Most Popular Reviews

Latest News Articles

Resources

PCW Evaluation Team

Azadeh Williams

HP OfficeJet Pro 8730

A smarter way to print for busy small business owners, combining speedy printing with scanning and copying, making it easier to produce high quality documents and images at a touch of a button.

Andrew Grant

HP OfficeJet Pro 8730

I've had a multifunction printer in the office going on 10 years now. It was a neat bit of kit back in the day -- print, copy, scan, fax -- when printing over WiFi felt a bit like magic. It’s seen better days though and an upgrade’s well overdue. This HP OfficeJet Pro 8730 looks like it ticks all the same boxes: print, copy, scan, and fax. (Really? Does anyone fax anything any more? I guess it's good to know the facility’s there, just in case.) Printing over WiFi is more-or- less standard these days.

Ed Dawson

HP OfficeJet Pro 8730

As a freelance writer who is always on the go, I like my technology to be both efficient and effective so I can do my job well. The HP OfficeJet Pro 8730 Inkjet Printer ticks all the boxes in terms of form factor, performance and user interface.

Michael Hargreaves

Windows 10 for Business / Dell XPS 13

I’d happily recommend this touchscreen laptop and Windows 10 as a great way to get serious work done at a desk or on the road.

Aysha Strobbe

Windows 10 / HP Spectre x360

Ultimately, I think the Windows 10 environment is excellent for me as it caters for so many different uses. The inclusion of the Xbox app is also great for when you need some downtime too!

Mark Escubio

Windows 10 / Lenovo Yoga 910

For me, the Xbox Play Anywhere is a great new feature as it allows you to play your current Xbox games with higher resolutions and better graphics without forking out extra cash for another copy. Although available titles are still scarce, but I’m sure it will grow in time.

Featured Content

Latest Jobs

Don’t have an account? Sign up here

Don't have an account? Sign up now

Forgot password?