Featured Research

from universities, journals, and other organizations

Inkblots improve security of online passwords

Date:
November 7, 2013
Source:
Carnegie Mellon University
Summary:
Computer scientists have developed a new password system that incorporates inkblots to provide an extra measure of protection when, as so often occurs, lists of passwords get stolen from websites. This new type of password, dubbed a GOTCHA (Generating panOptic Turing Tests to Tell Computers and Humans Apart), would be suitable for protecting high-value accounts, such as bank accounts, medical records and other sensitive information.

The GOTCHA password system developed at Carnegie Mellon University incorporates randomly generated inkblots and descriptions users assign to those images, such as this one, "A robot preparing to jump."
Credit: Carnegie Mellon University

Carnegie Mellon University computer scientists have developed a new password system that incorporates inkblots to provide an extra measure of protection when, as so often occurs, lists of passwords get stolen from websites.

This new type of password, dubbed a GOTCHA (Generating panOptic Turing Tests to Tell Computers and Humans Apart), would be suitable for protecting high-value accounts, such as bank accounts, medical records and other sensitive information.

To create a GOTCHA, a user chooses a password and a computer then generates several random, multi-colored inkblots. The user describes each inkblot with a text phrase. These phrases are then stored in a random order along with the password. When the user returns to the site and signs in with the password, the inkblots are displayed again along with the list of descriptive phrases; the user then matches each phrase with the appropriate inkblot.

"These are puzzles that are easy for a human to solve, but hard for a computer to solve, even if it has the random bits used to generate the puzzle," said Jeremiah Blocki, a Ph.D. student in computer science who developed GOTCHAs along with Manuel Blum, professor of computer science, and Anupam Datta, associate professor of computer science and electrical and computer engineering.

These puzzles would prove significant when security breaches of websites result in the loss of millions of user passwords -- a common occurrence that has plagued such companies as LinkedIn, Sony and Gawker. These passwords are stored as cryptographic hash functions, in which passwords of any length are converted into strings of bits of uniform length. A thief can't readily decipher these hashes, but can mount what's called an automated offline dictionary attack. Computers today can evaluate as many as 250 million possible hash values every second, Blocki noted.

Given the continued popularity of easy passwords, such as "123456" or "password," it's not always difficult to crack these hashes. But even hard passwords are vulnerable to the latest brute force methods, Blocki said.

In the case of a GOTCHA, however, a computer program alone wouldn't be enough to break into an account.

"To crack the user's password offline, the adversary must simultaneously guess the user's password and the answer to the corresponding puzzle," Datta said. "A computer can't do that alone. And if the computer must constantly interact with a human to solve the puzzle, it no longer can bring its brute force to bear to crack hashes."

The researchers described GOTCHAs at the Association for Computing Machinery's Workshop on Artificial Intelligence and Security in Berlin, Germany, Nov. 4.

Because the user's descriptive phrases for inkblots are stored, users don't have to memorize their descriptions, but have to be able to pick them out from a list. To see if people could do this reliably, the researchers performed a user study with 70 people hired through Mechanical Turk. First, each user was asked to describe 10 inkblots with creative titles, such as "evil clown" or "lady with poofy dress." Ten days later, they were asked to match those titles with the inkblots. Of the 58 participants who participated in the second round of testing, one-third correctly matched all of the inkblots and more than two-thirds got half right.

Blocki said the design of the user study, including financial incentives that were too low, might account for the less-than-stellar performance. But he said there also are ways to make descriptions more memorable. One way would be to use more elaborate stories, such as "a happy guy on the ground protecting himself from ticklers."

The researchers also have invited fellow security researchers to apply artificial intelligence techniques to try to attack the GOTCHA password scheme. Their GOTCHA Challenge is online at http://www.cs.cmu.edu/~jblocki/GOTCHA-Challenge.html


Story Source:

The above story is based on materials provided by Carnegie Mellon University. Note: Materials may be edited for content and length.


Cite This Page:

Carnegie Mellon University. "Inkblots improve security of online passwords." ScienceDaily. ScienceDaily, 7 November 2013. <www.sciencedaily.com/releases/2013/11/131107123238.htm>.
Carnegie Mellon University. (2013, November 7). Inkblots improve security of online passwords. ScienceDaily. Retrieved September 1, 2014 from www.sciencedaily.com/releases/2013/11/131107123238.htm
Carnegie Mellon University. "Inkblots improve security of online passwords." ScienceDaily. www.sciencedaily.com/releases/2013/11/131107123238.htm (accessed September 1, 2014).

Share This




More Computers & Math News

Monday, September 1, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Apple's Rumored iWatch Could Cost $400

Apple's Rumored iWatch Could Cost $400

Newsy (Aug. 31, 2014) Apple is expected to charge a premium for its still-rumored wearable device. Video provided by Newsy
Powered by NewsLook.com
Young Entrepreneurs Get $100,000, If They Quit School

Young Entrepreneurs Get $100,000, If They Quit School

AFP (Aug. 29, 2014) Twenty college-age students are getting 100,000 dollars from a Silicon Valley leader and a chance to live in San Francisco in order to work on the start-up project of their dreams, but they have to quit school first. Duration: 02:20 Video provided by AFP
Powered by NewsLook.com
JPMorgan Chase Confirms Possible Cyber Attack

JPMorgan Chase Confirms Possible Cyber Attack

Reuters - US Online Video (Aug. 28, 2014) Attackers stole checking and savings account information and lots of other data from JPMorgan Chase, according to the New York Times. Other banks are believed to be victims as well. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
Spend 2 Minutes Watching This Smartwatch Roundup

Spend 2 Minutes Watching This Smartwatch Roundup

Newsy (Aug. 28, 2014) LG announces a round-faced smartwatch, Samsung adds 3G connectivity to its latest wearable, and Apple will reportedly announce the iWatch on Sept. 9. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins