Schneier on Security

Clive Robinson • May 4, 2017 11:37 AM

@ Bruce,

I don't think we're ready for this. We use people's voices to authenticate them all the time, in all sorts of different ways.

As a species "we are never ready" for what comes along, we learn to adapt through experience, it's probably our strongest survival skill.

In the army they used to teach those in the technical and leadership sides "Stop Assess Think Act" (SATA) for situations outside of standard training. In civi street you tend to hear people refering to "sleep walking into a situation" or "fools rush in" for people that don't practice SATA.

Spoken conversation works at many levels you often get told that 80% of communications is non verbal. The thing is the same applies at the end of an audio link such as a phone or two way radio. It's not just the voice being recognised, it's the subject matter, the words and phrases, and intonation as well as the thinking of "does this make sense".

Thus if photoshoping a voice does become understood people will adapt and use checking of various forms.

If you think back when fax machines first became used people did not immediately treat them as different from posted documents. However after one or two frauds against banks people wised up. We are currently going through a phase of virtual companies using electronic messaging to submit invoices that are fraudulent but people are wising up and flaging things that don't look right and using other channels to verify the messages.

Thus after an initial problematic period I suspect people will adapt as the almost always do.

Clive Robinson • May 4, 2017 11:51 AM

@ CallMeLate...,

What *social* good does a persuasive voice-faking system/device provide?

Well the film industry has been doing it for years, after all how many actors can actually sing in a pleasant way? That's why they "voice over".

You might have seen an advert for a well known bar of chocolate, that uses Audrey Hepburn's face synced up onto the image of a body double. Some actors are now selling "future rights" to their image using such technology, therefore doing the voice as well is a logical step.

However this does bring up a thought, could the technology be used to make a tone deaf person sing like a lark without all that serious studio time? If it can expect it on an X-Factor boy/girl band near you any time soon ;-)

Clive Robinson • May 4, 2017 6:01 PM

@ Lawrence D’Oliveiro,

In the future, everybody will sound like Doctor Bot from Space Station 76.

I'd rather sound like "The Robot Devil" from Futurama, much more urbain 0:)

Clive Robinson • May 5, 2017 1:34 AM

@ Chris Abbott,

I've heard of things like this as well as ways to actually fake video of people saying things that will become easier and cheaper in the future.

AS I mentioned above, it's already been done in Ads and the entertainment industry but is currently expensive and not real time (but that will change). If and when holographic projection becomes indiscernable to the human eye the fun will really start, as it will then start to be possible to make faux / apparently "in person" attacks.

Which gives rise to,

2FA (maybe 3 or 4FA) (digital signature, security questions, etc.) before verifying any form of communication as authentic could be the only solution.

All of those systems require an initial "secure path" to exchange some form of "secret" securely or a method to authenticate the "meatsack" is who it claims to be. You only have to look at the mess PKI CA's have become to realise why authentication is a complete fail at the top level down[1].

The customary "secure path" is for an unknown individual to "present themselves 'in person' with 'credentials' in hand". We know the system is fallible due to the likes of people successfully travelling on stolen but valid credentials (obtained via "ID Shopping"). But it's been publicly known since the publishing of "The Day of the Jackal" by English author Frederick Forsyth[2]. That for those with a little time and foresight obtaining the root ID document of the "birth certificate" has several really easy to exploit security weaknesses. Once obtained a birth certificate will enable you to then get a passport, then a driving licence, then a bank account and so on until you have a complete set of false, but totally valid and verifiable as such, credentials.

Thus with the "official" ID process effectively unsecurable, the older human "trust model" is the fall back. But that likewise fails if people have sufficient time and resources to carry it out...

[1] In Nov 2005 the ex-head of the UK's MI5 Stella Rimington shot the nascent plans for a National ID system down. By simply pointing out the UK IC had no confidence in ID systems. Because there was no way to actually prove who you are as all ID could be forged or incorrectly issued or stolen (something the Israeli IC has long been known to do on an industrial scale).

[2] Coincidently Fredrick Forsyth has claimed to have been part of the UK's MI6 for a couple of decades. Originally what later became MI6 was back in WWI run under the cover of the Passport Office...

Clive Robinson • May 5, 2017 8:16 AM

@ Bob Paddock,

Anyone ever consider the security risks of involuntarily modifying a persons perception of time?

In what way?

Criminals discovered more than a century ago that rendering a night watchman / guard unconcious in one way or another, would negate their ability to raise an alarm...

It's one reason why some places gave the watchman a funny looking key they had to go and turn in boxes mounted at various points in their "round". Whilst many only contained a slow turn clock motor and strip of paper the key printed a symbol on to log the number of rounds and when, some also contained a resetable countdown timer that closed a set of alarm contacts wired up to a central office so that other guards would come and investigate.

Clive Robinson • May 13, 2017 5:26 AM

@ Chris,

They fool the system successfully against 33% of intended victims.

All the so called "practical biometrics" currently have both false positives and false negatives in the 10-40% range. For many it's a tunable option you adjust for less false positives you get a consequent rise in false negatives and the other way around.

This 10-40% range is due to a number of causes, the first is insufficient measurment range, the second is due to signal to noise issues. Each system has it's own particular set of "types" of these issues.

Thus often what looks good in "lab conditions" often looks realy bad in more "real world conditions".

Which is one of the reasons I suspect that moving DNA checks out of the lab and into the everyday environment will be at best unriliable and worse realy not posible.

The oddity is thus eye scans, humans like to be able to see thus the arangment of the eye is to keep dust, grit and other "environmental noise and distortions" out of the system. That is the eye is usually close enough to lab conditions thus it's the measuring head of the instrument that is going to be the main limit currently.

But as you might expect "voice" realy is going to be the worst of it. Even after thousands of generations human hearing real is not capable of distinquishing a persons voice from a mimic, which is why in our brains we have so many other check mechanisms. Basicaly the spoken word and sentances have a very very high rate of redundancy and above this is the idea of context as well... Thus it's easy to slide even poor fakes in through the redundancy.