In the wake of a series of very high-profile password leaks, Brian Krebs talks to security researcher Thomas H. Ptacek about the best practices for securing passwords. The trick isn't to merely hash with a good salt -- you must use a slow password hash that takes a lot of work, so that making rainbow tables is impractical.
Ptacek: The difference between a cryptographic hash and a password storage hash is that a cryptographic hash is designed to be very, very fast. And it has to be because it’s designed to be used in things like IP-sec. On a packet-by-packet basis, every time a packet hits an Ethernet card, these are things that have to run fast enough to add no discernible latencies to traffic going through Internet routers and things like that. And so the core design goal for cryptographic hashes is to make them lightning fast.
Well, that’s the opposite of what you want with a password hash. You want a password hash to be very slow. The reason for that is a normal user logs in once or twice a day if that — maybe they mistype their password, and have to log in twice or whatever. But in most cases, there are very few interactions the normal user has with a web site with a password hash. Very little of the overhead in running a Web application comes from your password hashing. But if you think about what an attacker has to do, they have a file full of hashes, and they have to try zillions of password combinations against every one of those hashes. For them, if you make a password hash take longer, that’s murder on them.
So, if you use a modern password hash — even if you are hardware accelerated, even if you designed your own circuits to do password hashing, there are modern, secure password hashes that would take hundreds or thousands of years to test passwords on.
The problem is that you really need to make this design decision from the start -- it's hard to retrofit once you've got millions of users.
How Companies Can Beef Up Password Security
A long time ago, Veronica Belmont was featured in a blooper reel for her old TV show in which she clowned around with a Cthulhu t-shirt, wiggling back and forth and saying “So lifelike.” A creepy Internet person turned the moment into a GIF that has followed her around ever since, so that other creepy […]
Last February, Lenovo shocked its security-conscious customers by pre-installing its own, self-signed root certificates on the machines it sold. These certificates, provided by a spyware advertising company called Superfish, made it possible for attackers create “secure” connections to undetectable fake versions of banking sites, corporate intranets, webmail providers, etc.
Today and tomorrow only we are offering an additional 15% off the entire Boing Boing store (some exclusions may apply). Simply use coupon code: BLACKFRIDAY at checkout! Below are a few of our favorites from the store: First Generation Lytro 16GB Camera: The First Consumer Camera to Capture the Entire Light FieldAdobe Training Videos: Lifetime Subscription: 6,000+ Adobe […]
Today only in the Boing Boing Store we are offering an extra 15% off of the below VPN deals just use coupon code: VPN15 at checkout. proXPN VPN: Premium Lifetime Subscription Surf the web with ultimate peace of mind – both at home and on the road – over proXPN’s fully-encrypted, lightning-fast servers. Your lifetime premium subscription […]
These knitted gloves are here to save the day (and your hands) with an ultra-comfy, double-layer that will allow you to stay warm and use your phone. Now you can take photos on the fly, text, Tinder, and more without letting freezing temperatures get in your way. Plus they work with all touchscreens, so no […]