Feeds

Crypto-boffins propose safer buddy list protocol

Presence services with less privacy risk

  • alert
  • submit to reddit

The Power of One eBook: Top reasons to choose HP BladeSystem

One of the attractions of presence in communications services is that you know someone's available before you try to contact them. The flipside is that presence is also inimical to privacy. Now, a group of researchers has put forward a way to improve privacy of “buddy lists” but still allowing friends to know each others' presence.

Outlined in this paper, the presence system, referred to as DP5, has been developed by boffins from the University of Illinois, University College London, and the University of Waterloo in Canada.

DP5 proposes a mechanism in which users' buddy lists are encrypted but can still be interrogated. As they explain, the system also protects users against having their buddy lists compromised in case of an attack against a service: “While infrastructure services are required for DP5 to operate, they are designed to not require any long-term secrets and provide perfect forward secrecy in case of compromise”.

That's because the encryption of the presence information prevents the service from learning private information like users' lists of friends.

The paper also notes that with the experience of Lavabit and the Snowden revelations as examples, it's probably a good idea for anyone trying to pitch a “secure online messaging” service to avoid collecting privacy-sensitive metadata.

The basis of registering someone as a friend is simple: instead of a central server holding user IDs and building a topology of connections between users, individual users use each others' crypto keys to send, receive, and approve friend connections.

Because the server has to know something about relationships, what's stored in the database is a crypto key indicating a user's “directed friend link”. This, however, is not a permanent record of the link: periodically, each user's client will regenerate the keys the system stores: “Alice picks a random private key … and derives a fresh public key. Then for each of her friends, she derives the shared key for the long-term epoch, and encodes a database entry comprising an identifier, and a ciphertext of her fresh public key.” ®

The Power of One eBook: Top reasons to choose HP BladeSystem

More from The Register

next story
BMW's ConnectedDrive falls over, bosses blame upgrade snafu
Traffic flows up 20% as motorway middle lanes miraculously unclog
LibreSSL RNG bug fix: What's all the forking fuss about, ask devs
Blow to bit-spitter 'tis but a flesh wound, claim team
Mozilla fixes CRITICAL security holes in Firefox, urges v31 upgrade
Misc memory hazards 'could be exploited' - and guess what, one's a Javascript vuln
Putin: Crack Tor for me and I'll make you a MILLIONAIRE
Russian Interior Ministry offers big pile o' roubles for busting pro-privacy browser
Manic malware Mayhem spreads through Linux, FreeBSD web servers
And how Google could cripple infection rate in a second
Don't look, Snowden: Security biz chases Tails with zero-day flaws alert
Exodus vows not to sell secrets of whistleblower's favorite OS
Roll out the welcome mat to hackers and crackers
Security chap pens guide to bug bounty programs that won't fail like Yahoo!'s
Researcher sat on critical IE bugs for THREE YEARS
VUPEN waited for Pwn2Own cash while IE's sandbox leaked
prev story

Whitepapers

Top three mobile application threats
Prevent sensitive data leakage over insecure channels or stolen mobile devices.
Implementing global e-invoicing with guaranteed legal certainty
Explaining the role local tax compliance plays in successful supply chain management and e-business and how leading global brands are addressing this.
Top 8 considerations to enable and simplify mobility
In this whitepaper learn how to successfully add mobile capabilities simply and cost effectively.
Application security programs and practises
Follow a few strategies and your organization can gain the full benefits of open source and the cloud without compromising the security of your applications.
The Essential Guide to IT Transformation
ServiceNow discusses three IT transformations that can help CIO's automate IT services to transform IT and the enterprise.