Pioneer In Internet Anonymity Hands FBI A Huge Gift In Building Dangerous Backdoored Encryption System

from the not-a-good-idea dept

I first came across cryptography pioneer David Chaum about a decade ago, during the debates about online voting. Many in the technology world were insisting that such things were impossible to do safely, but Chaum insisted he had come up with a way to do online voting safely (he’d also tried to do electronic money, DigiCash… unsuccessfully). Many people disagreed with Chaum and it led to some fairly epic discussions. It appears that Chaum is again making moves that are making many of his colleagues angry: specifically creating a backdoored encryption system.

Few doubt Chaum’s cryptography skills or pedigree. He was instrumental in the early days of computer cryptography and what anonymity we have online today owes a lot to Chaum. But his latest plan is… troubling:

At the Real World Crypto conference at Stanford University today, Chaum plans to present for the first time a new encryption scheme he calls PrivaTegrity. Like other tools Chaum has spent his long career developing, PrivaTegrity is designed to allow fully secret, anonymous communications that no eavesdropper can crack, whether a hacker or an intelligence agency.

That part sounds good, right? But then there’s this:

That ambitious privacy toolset aside, Chaum is also building into PrivaTegrity another feature that?s sure to be far more controversial: a carefully controlled backdoor that allows anyone doing something ?generally recognized as evil? to have their anonymity and privacy stripped altogether.

Whoever controls that backdoor within PrivaTegrity would have the power to decide who counts as ?evil??too much power, Chaum recognizes, for any single company or government. So he?s given the task to a sort of council system. When PrivaTegrity?s setup is complete, nine server administrators in nine different countries would all need to cooperate to trace criminals within the network and decrypt their communications. The result, Chaum argues, is a new approach that ?breaks the crypto wars,? satisfying both the law enforcement agencies who argue that encryption offers a haven for criminals, and also those who argue that it?s necessary to hobble mass spying.

Unfortunately, Chaum is both totally missing the point and playing right into the FBI’s hands. The argument of basically every other cryptographer is that building any encryption system is incredibly difficult — and introducing any sort of backdoor opens up massive and dangerous vulnerabilities — whether the original creators recognize it or not. The second you introduce a backdoor — even using Chaum’s weird “nine people in nine countries” system — you have introduced a vulnerability. A vulnerability that can and will be abused by others. You are introducing a security flaw. And that’s a massive security problem.

Chaum’s bragging about this system totally misses this point:

?If you want a way to solve this apparent logjam, here it is,? says Chaum. ?We don?t have to give up on privacy. We don?t have to allow terrorists and drug dealers to use it. We can have a civil society electronically without the possibility of covert mass surveillance.?

That assumes that his system can’t be hacked. That’s a dangerous claim. Yes, the “key” is split into 9 pieces, but it’s still introducing a vulnerability and undermining the integrity of the system.

And, worst of all, as ACLU security expert Chris Soghoian points out, this is little more than a huge political gift to the FBI, who can go back to their stupid claims that if technologists just work harder they can come up with a “solution” to the false problem of “going dark.” Similarly, you have politicians like Hillary Clinton insisting that if only techies come together with government they can “solve” the encryption/”going dark” issue.

And now you can bet, without a doubt, that law enforcement and clueless politicians will start pointing to Chaum’s offering as an example of a “solution.”

But, as Soghoian points out, that misses the point. Chaum is creating a technology that is, by default, less secure and comes with vulnerabilities built in. It’s no secret that it’s possible to build backdoored encryption. Hell, just about anyone could do that. The “impossible” part that people are warning about is building such a system that is actually secure. Chaum’s is not. By default, it has vulnerabilities built in, and they will get exploited. And, even before the technology is exploited, the existence of this will be exploited by politicians and law enforcement to undermine arguments for strong encryption.

And, of course, none of PrivaTegrity’s security claims have been checked or audited publicly at this point. Chaum admits that while the eventual plan will involve routing messages (multiple times) though nine servers in nine different countries, the prototype runs entirely on Amazon’s cloud computing infrastructure. Either way, at the very least, the system makes it clear that decrypting all such traffic requires attacking and compromising just nine servers. If you don’t think the NSA can do that, you haven’t been paying attention.

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Comments on “Pioneer In Internet Anonymity Hands FBI A Huge Gift In Building Dangerous Backdoored Encryption System”

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That One Guy (profile) says:

'Secure' communications that aren't

This claim…

Like other tools Chaum has spent his long career developing, PrivaTegrity is designed to allow fully secret, anonymous communications that no eavesdropper can crack, whether a hacker or an intelligence agency.

Is completely and utterly undercut by this part…

That ambitious privacy toolset aside, Chaum is also building into PrivaTegrity another feature that’s sure to be far more controversial: a carefully controlled backdoor that allows anyone doing something “generally recognized as evil” to have their anonymity and privacy stripped altogether.

As far as I can tell, there is one way the first statement can be true given the second one, and that is no ‘hacker or an intelligence agency’ needs to crack the system, because it starts out that way.

If the system allows anyone to strip those using it of their privacy and anonymity, then that flaw will be found, with the easiest method simply finding the nine ‘council members’ and getting their individual pieces of the decryption key. Given they have to have a way to communication between each other and Chaum, that task should be trivially easy given the resources the various spy agencies have to throw at the problem, and once that’s done, the entire system is compromised.

I hope the FBI and/or NSA sends the guy a nice fruit basket or job offer, because with this colossal blunder he might as well be working for them already.

Ninja (profile) says:

Re: 'Secure' communications that aren't

Don’t you think the intelligence agencies tried to $$$ convince $$$ the least ethical of the guys working with cryptography till they found one that was up for sale? I also find it quite hard to believe they are as stupid as to believe a backdoor isn’t going to be exploited. The idea, I’d guess, is to use a good encryption for the things that need such security and where the money is (ie: banks) while the rest of the population is forced into the non-encryption encryption, collateral damages be damned as long as they can inject control and indoctrinate the citizenry into an obeying mass. Sounds good enough?

Ryunosuke (profile) says:

Re: Seen before

Three Keys for the Presidential Nominees under the sky,
Seven for the Congressional Lords in their halls of stone,
Nine for Terrorists doomed to die,
One for the Dark Lord on the Firearms throne,
In the land of the Free where the Shadows lie,
One key to rule them all, one key to find them,
One key to bring them all and in the darkness bind them
In the Land of the Free where the Shadows lie.

/edited for artistic freedom

Anonymous Coward says:

Re: Re: Re: Better Idea

There is a difference between a good crypts system, and a broken one known to have a fixed inbuilt key. If it took one month per message, then it takes 1,00 months, or 1,00 times the processors to break 1,000 messages for a good, (but by modern standards weak), crypto. However with the backdoot, it only takes one month to break every message past and future that uses the backdoored system. The backdoor makes it worth throwing every available spare, or botnet, CPU cycle at finding the backdoor because the pay-off of doing so is so big.
Further, every part of the nine part key that can be obtained by any means just makes the problem simpler. When the key holders accede to some reasonable request, it is likely that some or all of their systems will have been compromised to gain parts of the key. The idea of any single key, no matter how divided, give a single point of attack to compromise any message, and is a monumentally stupid idea because once it has been obtained all communications using the system are compromised.
Given such a weak point the NSA will be one of the first to compromise the system, but they will not be the only ones.

Anonymous Coward says:

You can split the decryption key into as many parts as there are members of the UN and it wouldn’t matter. A key to a back door, is a key to a back door. Either the keys will be stolen (it would be a high priority for the NSA and their international counterparts and adversaries), or hackers will simply crack the encryption themselves. Within months, any traffic “secured” by such an encryption scheme would no longer be secure.

Then there’s the the chicken and egg problem they’ve got going. The only real way to tell if encrypted traffic is “doing something evil” is to decrypt it. So if an agreement that the traffic needs to be decrypted calls for that, either no traffic will be decrypted, or all traffic will be decrytped upon request.

That doesn’t even begin to getting to the problem of getting people to actual use this.

DannyB (profile) says:

Re: Re:

Two problems you point out:
1. chicken and egg problem, The only real way to tell if encrypted traffic is “doing something evil” is to decrypt it.
2. the problem of getting people to actual use this.

The two problems interact and solve each other.

Evil traffic is indicated by the fact that it is encrypted and NOT using this insecure scheme.

The way you get people to use the insecure scheme is to have a horiffical terrorful punishment for not using it. Other regimes have done similar things and the past.

After all, it’s for your own security.

For your own security, use insecure security. Used by all oxymorons.

lars626 (profile) says:

Two possibilities

I see two possibilities here.
1. Chaum is an incredibly naive nerd that really does not understand the actual issue.
2. He is not getting the attention he things he should for his work and figures that his system will be a wonderful pr tool.
Possibly both.

Besides, how do you select the nine persons with keys? How do you guarantee they are not compromised. Any reliance on the human elements is doomed to fail.

DannyB (profile) says:

Re: Two possibilities

Another possibility:
3. He is not an incredibly naive nerd, understands the actual issue perfectly well, and based on his understanding comes up with this proposal.

If true, what would that tell you?

As for your other questions:

Q. How do you select the nine persons with keys?
A1. By lottery.
A2. By a national to the death steel cage match to find the nine toughest people.
A3. Based on the size of their, um . . ., bank account.
A4. Save a lot of time and trouble by letting the US Congress appoint them via secret proceedings. And keep the identities of the nine golden key holders a secret.

[que song: ’cause I’ve got a golden key! to tune from Charlie and the Chocolate factory.]

Q. How do you guarantee that the golden keys are not compromised?
A. In the event of a key compromise the government would be obligated by law to publish a notice in the bottom of a locked filing cabinet stuck in a disused lavatory with a sign on the door saying ‘Beware of the Leopard.”

Socrates says:

Re: Re: The canary birt in the cold mine

3. He is not an incredibly naive nerd, understands the actual issue perfectly well, and based on his understanding comes up with this proposal.

The regime may have hurt him, or convinced him of their ability and willingness to hurt him.

David Chaum’s absurd proposal might be an attempt to say what they want to hear while assuring that no sane person fall for it. Whether or not it is intentional, nothing he says henceforth should ever again be taken seriously.

Perhaps it is his Truecrypt “bitlocker” advise?

DannyB (profile) says:

carefully controlled backdoor

Golden Keys are just back doors by another deceptive name.

Haven’t all past notions of introducing back doors ASSUMED that the back door would be carefully controlled?

Or are the ‘golden key’ advocates thinking they can pass out the golden keys like candy at Halloween?

Just because Chaum’s golden key would be ‘carefully controlled’ doesn’t make his argument any different different. All the past objections to backdoors WERE about ‘carefully’ controlled back doors, or golden keys, or whatever you want to call them.

The problem is: what happens once the backdoor is hacked by the Russians, the Chinese, Anonymous, the NSA or other bad actors?

Anonymous Coward says:

From the linked Wired article:

“Chaum has yet to reveal the full list of the countries where PrivaTegrity would place its servers. But he suggests they’ll be in the jurisdiction of democratic governments, and names Switzerland, Canada and Iceland as examples”

Of course Russia, India, China, Pakistan, NK, Saudi Arabia and so on will agree to let their citizens use this wondrous technology, worldwide success is guaranteed, and peace and harmony will descend over the planet.

That One Guy (profile) says:

Re: Re: Re:

I think the FBI, the NSA, the CIA, Congress, and Dianne Feinstein will trip over one another trying to accept it first.


I think the FBI, the NSA, the CIA, Congress, and Dianne Feinstein will trip over one another trying to force other people to use it first.

They don’t want their communications to be decryptable, they want everyone else’s communications to be decryptable.

DannyB (profile) says:

Security experts: Backdoors weaken security. They’re a bad idea.
Chaum: I’ve built a new system with a backdoor.
FBI: See? It is possible.

The question is NOT whether you can build a system with a back door. That is a trivial exercise.

The question IS whether you can build a SECURE system with a back door.

The answer is: NO

Therefore the FIB wants to force an insecure system upon everyone.

sigalrm (profile) says:

Technology aside, there's this other little issue...

Ok, so the points about the technology are spot on. But no one has commented on the other problem:

Assuming the system worked as advertised (which, lets face it, you may as well assume the assistance of a perfectly spherical purple cow):

Good luck finding 9 people globally who are both smart and ethical enough to make a legitimate “Good/Evil” decision _and_ stupid enough to attract the attention of every intelligence organization on the planet to themselves and their families.

Anonymous Coward says:

Knowing there is a backdoor is sufficient to gain access to it. Nation states don’t play by the same rules as everyone else. They have fairly much unlimited funds, tons of manhours to throw at a problem, are willing to invest many more man hours than and individual group, and many, many, professional people to draw on their talents to obtain some desired goal.

What may not be able to be accomplished in one method can be in another. Bribery, setup for false charges for deal making, honeypots for embarrassment, blackmail; hell where does this list end? If you can’t get one of these administrators to deal, then there is always removal from the group or death to accomplish a much more favorable person to their way of seeing things.

If not this year when it comes out, then next year after it is no longer in the public eye. If that won’t work then the next year after that.

My point being you can’t measure nation states and how far they are willing to go by individual standards.

Anonymous Coward says:

Three Keys for the CIA agents under the sky,
Seven for the NSA in their halls of stone,
Nine for Mortal Men corrupted by greed,
One for the Dark Lord on his dark throne
In the Land of Langley where the Government lies.
One Key to rule them all, One Key to find them,
One Key to decrypt them all and in the courts convict them
In the Land of Langley where the Shadows lie.

Adrian Lopez says:

The problem is not technical, but human

Will the nine people in charge of the decryption key be operating independently as caped crusaders against the improper use of cryptography, or will they be working together with governments in deciding which messages get decrypted? Will they respond to court orders? Subpoenas? Requests from governments bent on catching political dissidents?

That Chaum thinks this is a good idea shows that geeks used to thinking technically can be very naive when it comes to thinking practically.

tqk (profile) says:

Re: Re: Re:

Or is obeying the law under pain of imprisonment.

A simpler and safer way of obeying that law is simply to assume encryption has been made illegal. Encryption is not the only way to pass secrets so I’ll use the other, less convenient, ways instead. What have they gained? Animosity. What have I lost? Convenience, and that’s all.

Stupid game. Their move.

testcore (profile) says:

Just saw the talk...

At the beginning, Chaum did acknowledge that some controversy does surround this proposal, then waved his hand and said, “I have no idea why.”

He then went on to completely omit the fact that there is this glaring security hole. Rather it’s left to an exercise for the reader. What a cowardly cop-out.

Oh, and he also stated that the system would have to run “in a highly secure data center managed by someone in this room”, ignoring the fact that most people in the room could also break in to such a “secure data center”.

Bad news all around.

That One Guy (profile) says:

Re: Re:

Unfortunately the problem with this system doesn’t require that anyone use it, it presents a problem simply by having been suggested, because those same idiots that have been insisting that tech companies can create ‘secure’ broken encryption if they just try harder will be holding this bit of idiocy up as ‘proof’ that their claims are reasonable.

With this moron’s actions the voyeurs will be re-energized, claiming that this is exactly what they were demanding, and if one person can do it, clearly other companies can do the same, completely ignoring that this ‘encryption’ system is useless, just as tech companies have been saying of any form of broken encryption.

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