back to article Brazilian banker's crypto baffles FBI

Cryptographic locks guarding the secret files of a Brazilian banker suspected of financial crimes have defeated law enforcement officials. Brazilian police seized five hard drives when they raided the Rio apartment of banker Daniel Dantas as part of Operation Satyagraha in July 2008. But subsequent efforts to decrypt files held …

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Finally ...

... a bank that takes encryption seriously!

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Headmaster

Uhm... No.

No the bank did not take security seriously. The dude that stole from the bank did.

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Boffin

@Uhm... No.

I think you need to re-read that with your Irony Detector switched on...

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USB to the rescue!

If I were that conscious about security, I would have a collection of seemingly-important files on a USB drive, one or more of which would be applied to generate a hash for encrypting valued data. Keep a backup somewhere safe and destroy the drive before a suspected apprehension.

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Giving up your keys

I wonder what the local plod would think if you did this and when asked for a copy of they keys, gave them a rather crushed USB stick. "They're on there, officer".

Keeping large files of random data on your hard disk may also cause confusion.

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FAIL

Hah right.

Refusing to give a password when ordered - Jail

Destroying evidence - More Jail

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Anonymous Coward

Keep a backup somewhere safe and destroy the drive before a suspected apprehension.

If you could be so certain of destroying the drive, why not just keep the files on the drive?

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FAIL

"Refusing to give a password when ordered - Jail"

Alternatively. if you RTFM then you know that "no such law exists in Brazil".

Fail --- fail again --- fail better.

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Flame

FAIL

efeffess uses the personal pronoun "I" indicating he is discussing his own attitudes to security. Unless he happens to live in Brazil I can't see how your post is relevant.

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N2

TrueCrypt

Rocks!

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Not forced to reveal

As its TrueCrypt it might have been an encrypted inner container, so if he could deny its existance and not have to give over the keys...

... maybe he had a really weak outter container, with no inner container and they spent all that time looking for one ^_^

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Anonymous Coward

Or......

If it was me, that second layer of encryption would be;

cat /dev/urandom > Super_Secret_files.encrypted.pgp

With the files stored (still encrypted) somewhere far less obvious!

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FAIL

All your crypt are belong to us

Good show!

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Can't reveal what I don't know...

Other people know parts of my pass keys.

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Anonymous Coward

Good password - a page of text

Now that's a decent password:

http://www.gutenberg.org/catalog/world/readfile?pageno=205&fk_files=873078

Or, conversely, pick a memorable line / chapter heading from a book and use the URL as a password. (Depends how confident your are on the website maintaining it URL scheme.)

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Stop

Very bad Idea, Indeed

"Or, conversely, pick a memorable line / chapter heading from a book"

Did it ever occur to you that USGOV spends billions per year on SIGINT ? I would not be surprised to see that they have their own web index and their own huge electronic library of the world's books. NSA is THE authoritative source for Arabic (!) Dictionaries, for example. And certainly they have access to whatever Google has scanned in the last few years.

I suggest to invent your own really silly phrase like:

"A japanese chicken went on holiday vacation to see the tower of pisa and to meet a distant relative. There she met a dog and they decided to marry in the vatican. Unfortunately the pope declined this saying the bible would not allow this. A classical story of japanese-italian love".

I read somewhere that a single letter of such nonsense prose contributes about 0,3 bits of entropy. So the above sentence would yield in the order of 80 bits of effective key length. I assume this is out of reach even for USGOV at the moment. 2^80 operations is quite a feat. If you want more bits, just continue the story.

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Joke

If you used aManFromMars Like Prose

..you would probably yield 0.9 bits/character

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Anonymous Coward

More precisely

it's 233 characters and 233*0.3==69,9 bits.

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Anonymous Coward

USG Web Indexing

works completely covertly. All they need to do is to tap the wire before Google datacenters. Everybody else, including Google, will think it never happened.

Also, they could just use all their "taps" worldwide to build a huge index. Which certainly includes a ton of email messages, stupid Powerpoint presentations, an large pile of excel files which they intercepted from all those antennas and taps.

They have more money than Google and they have demostrated their competence with SE Linux, so it is reasonable to expect them to also have more servers and harddisks than Google.

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Another way

If you use truly random words e.g. "Mt. whoa usurp mush naughty huge became" you get much more entropy per letter. That example should be worth 90 bits*. Certainly quicker to type, but which way is actually easier to remember is probably a matter of personal opinion.

*That is, assuming I generated it with the Diceware system (feel free to Google, Bing or Yahoo! it). But I admit I couldn't be bothered to get out my dice and just picked them "randomly" form a list.

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Alert

Re: Very bad Idea, Indeed

"I read somewhere that a single letter of such nonsense prose contributes about 0,3 bits of entropy. So the above sentence would yield in the order of 80 bits of effective key length. I assume this is out of reach even for USGOV at the moment. 2^80 operations is quite a feat. If you want more bits, just continue the story."

I think that should be your phrase...=P

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Boffin

re: More precisely

Even more precisely it's 281 characters including spaces and periods. It's 229 letters.

If it helps, put it in Excel and learn the LEN & SUBSTITUTE formulae.

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hmm...

It's estimated that Google have over a million servers.

http://lifehacker.com/5518303/remains-of-the-day-googles-1-million%252B-servers-edition

It seems unlikely the US Government would have so many.

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Joke

You are

..the beancounter of the month and will get an ugly looking medal from MerkinMedals(TM).

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Bronze badge

mural: yonder nor sorghum stenches

shut ewe ewes cymbal fray says four ink rip shuns.

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Or maybe it's all crap data in there

The best way to hide your secret sensitive data from police or others trying to get access to it is to get them fixed on a red herring.

A lot of random data bits encrypted using a known cryptography program and left out in the open should keep them occupied a very long time and keep them from looking for the true data.

Works for mail too. NSA would not be too happy, if we all started sending encrypted garbage to each other at random intervals. You can spend an infinite period trying to decrypt something that doesn't have any meaning in the first place. Meanwhile all the truly sensitive information is send using some other means (like maybe using the random crap in a previous file as a one time decryption key).

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FAIL

Electrodes and conductive gel.

Brute force techniques generally crack any password: you simply find someone that knows the password and apply brute-force to them until they tell you what it is.

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Security!

http://xkcd.com/538/

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Coat

You beat me to it...

also known as rubber-hose cryptoanalysis.

Mine's the one with the slightly dented large metal torch in the pocket.

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Just wondering...

I've noticed that nobody yet has taken a negative stance towards the (allegedly) criminal banker who has (allegedly) stolen money from us (as stealing money from companies inevitably results in ordinary people losing out).

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Re: Just wondering...

"I've noticed that nobody yet has taken a negative stance towards the (allegedly) criminal banker who has (allegedly) stolen money from us (as stealing money from companies inevitably results in ordinary people losing out)."

Possibly it's because people feel that allowing a minority of criminals to escape is an acceptable price for preventing state intrusion into the lives of the majority. It's similar to accepting that some criminals will go free if we have the presumption of innocence but fewer innocent people will be wrongfully convicted.

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IT Angle

from an IT angle

from a purely IT angle this is actually quite interesting in that it goes to prove the value of a good encryption technology and good password hygine (if that's the right phrase) ... so well done that Banker in using technology correctly for a chance (rather than to automate rip-off fees!)

on a more general level though I agree... if he's ripped off money from bank customers that hasn't been recovered then the folks in Brazil need a get a bit more creative in reovering the password... or at least the money.

Then again... don't we all assume banks aren't really in it because they love us...

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Badgers

Implied

The negative stance is implied by the fact that he is a banker. Any other misdeeds he has done are just added to the list.

For example, the fact that they lend up to 9 times the money that they actually started with, charging interest on it, which means that there is not actually enough money to pay off all the debt, because that much money does not exist.

Or the sociopathic ways that they treat everyone (customers, suppliers, staff...)

Most people seem to be concentrating on (and impressed by) the fact that the guy knew what he was doing (in any sphere of knowledge, let alone IT!).

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negative stance

Well as far as I'm aware he is still innocent. They haven't yet convicted him of anything yet have they?

We are all just happy that a bank somewhere in the world has heard of security.

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Pirate

And why is that?

You are right, of course.

And that's probably because most people here have a small truecrypt file somewhere. For dirty little secrets (ours or someone else's), a pr0n collection (if you happen to live in the UK) or just because we can.

We grew up reading cyberpunk novels. Techies are supposed to be able to use encryption software that the suits can't crack. We are ENTITLED.

Confirmation that a good encryption algorithm and a well chosen key can baffle the feds, pleases us. Thieving bankers, on the other hand, are the order of the day. Hardly newsworrthy.

Funny how the mind works.

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Big Brother

we're in the IT branch

yeah well of course it was wrong what he did, but he was very IT-professional about it. that's why we're a bit proud of him. "he's one of us"! ;)

the icon because well he's watching but that's it in this case.

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OK, maybe not negative stance

I wasn't quite meaning we should be Daily Mail "string 'im up" types, but the comments before were either "Wahay!" or joking. Nobody had started to think that maybe there is somewhere between total state surveillance and just letting people go because they use difficult cyphers. Both are the extreme viewpoints; I don't know what the middle ground is, but maybe a group of people together can come up with a better idea.

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Entirely true and I agree with you, but...

What happens when most of the criminals are knowledgeable enough to encrypt competently?

My guess is that the current state of affairs is not really all that different from laws that strongly limit the state's access to things like snail mail. Society functioned before with limited law enforcement access to personal correspondence, there is no reason it shouldn't in the future. The new tech just makes convenient for police to claim that things have changed and more access is needed.

Still... I wouldn't want to endlessly privilege privacy over criminal persecution capability _if_ there was a clear cut case for more snooping powers. Which there isn't, at this point.

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Flame

Dont we all love Bankers??

He stole the banks money. Since the Government is stealing our money and handing it to the banks it is only fair that *someone*, somewhere, gets something for our taxes!

I hope he blew it in style on Brazilian prostitutes and Coke.

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Pint

Re: I hope he blew it in style on Brazilian prostitutes and Coke.

Hear, hear. If you are going to steal/embezzle money, don't do something boring with it like properly invest it. You only live once, and money really isn't everything. If your regular life is so terrible that you feel the need for greed, go whole hog.

I have to admit to having less of a soft spot for people who embezzle in order to buy a sports car and a second house. I mean, really? If you are doing it, you will eventually be caught, so live it up while you can.

If you decide on a life of crime, then live fast, die young, and leave a bloated corpse.

Sound investing is for us stodgy types who obey the rules.

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Brazil is neither the UK nor the USA

It depends a lot on how much you can trust the legal system. The USA is a big country, with a lot going on, and we tend to hear of exceptional events, but those events include a lot of apparently dodgy issuing of search warrants.

On something such as this case, whichever country we're in, can we trust a judge to be more discerning than a plain rubber-stamped signature on a Police request?

And, if the NSA were unleashed on this problem, what could they say in court to prove that what they found was really on the drive? It's a kind of magic?

The UK system isn't all that good, but it's an attempt to get around that little problem. And in the USA one could invoke the Fifth Amendment, though that has pitfalls for the unwary.

In Brazil? Well, any country, this guy likely has enough money for lawyers that you'd have to be careful.

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I have a feeling ..

.. that slightly less legal methods of extraction will result if the people he ripped money from ever get hold of him.

However, you should see this in context of the greater principle here: citizens now so worried about government interference in their lives that it upvotes what appears to be a criminal.

I like the 180 degree twist here: this is technology that has been used for evil, but can also be used for good. Usually the considerations are the other way round..

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Welcome

once again...

in UK we:

a. 'have the right to remain silent' so we don't have to incriminate ourselves... or:

b. 'have to disclose encryption keys if required by law enforcement' or face jail.

it cannot be that both are true. it can olny be either one or the other.

what i need to know is: which one is it then?

DUH !!!

PS: agreed. truecrypt rocks !!

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FAIL

Right to silence

In the UK we lost the right to remain silent during Maggie's era due to the fact that we kept having to let IRA terrorists go because they would go silent as soon as they were arrested - including never saying their name. The first time they would speak would be to friends they met in the Maze prison. You now have a right to remain silent, so long as you understand that the silence can be used as evidence against you. In the case of an encryption key the law is more specific, but if you don't tell them the key, they are allowed to use that fact to deduce that you have naughty stuff in the files.

Now, despite the fact that I was a serving member of the Armed Forces during the troubles and every time I got in my car for about 10 years I had to get on the floor and search underneath it to check for bombs, I vehemently disagree with this policy, but it is the UK law.

Furthermore, in another area of self-incrimination, namely speed cameras, the European Court of Human Rights has ruled that you can be required to self incriminate with speed cameras, despite self-incrimination being ruled out in the ECHR, somewhat like the 5th amendment in the US. I suspect that the encryption law could be taken to the European Court of Human Rights, but I suspect just like speed cameras it would be ruled a permissible law. The ECHR is generally much more flexible than the US constitution.

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not what we told, is it ?

thanks AC, that is good information.

If you are told by a policeman while getting arrested: "you have the right to remain silent", then surely this is really not true. ergo a lie. so, would that constitute false arrest ?

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They say a little more...

..from some website somewhere where copper talk:

"You do not have to say anything but it may harm your defence if you do not mention when questioned something you later rely on in court. Anything you say may be given in evidence"

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JV

Brute force

Is there a brute force indexer somewhere? Something that shows how many possibilities per second per Ghz can be decrypted?

I know I'm safe, my password is insane, but what's the minimum to keep a password safe from a supercomputer for a year or 2... Don't suppose theres a scale for them somewhere?

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Anonymous Coward

Not meaningfully, no

As while things scale linearly for key space bruteforcing for most people, all bets would be off if the NSA get involved. They aren't just the world's largest employer of mathematicians and user of traditional computer equipment, they have some other tricks up their sleeve.

That's all I would feel confident saying.

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Grenade

Understand the extremes

There are 2 ways to crack encryption if the algorithm itself has no flaw that permits a key reduction attack (beyond the scope of this post by the way). The first is a brute force attack, the second is a lookup attack.

Starting with the lookup attack. This involves storing a set of possible phrases encrypted with every possible key in a big database that is indexed using a hash. The possible phrases include things like zip file headers, as well as common words and phrases in many languages. All you do then is take every sequential set of bits in the message and look it up in the database. If you get a hit that gives you a possible candidate key, then you decrypt with all candidate keys and you get the message back. It allows you to crack encryption in realtime, and was widely rumoured to be the way that the NSA was reading DES (40 bit and 56 bit). If you have a 256 bit key, and you can store a Gb of data on a drive weighing a gram, then a lookup attack requires a drive so heavy that it will collapse into a black hole.

Now, with a brute-force attack. You can figure out with basic thermodynamics, the minimum energy needed to flip a bit in a state computer. Therefore you can figure out the energy requirements to count through all the keys in a given key length. If you put a Dyson sphere around the sun and trap all its energy for the rest of the Sun's life, you cannot get a state machine to count up to 2^256.

Therefore, to all intents and purposes a 256 bit symmetric key is safe.

As the article points out though, you usually lose out because of an implementation flaw - for example, your encryption key could get left in a swap file, or something similar. Making an algorithm that is perfectly safe is actually kind of tricky. If I was going to try I would have a dedicated machine that ran a cut-down OS where file writes were intercepted and only permitted if certified encrypted; and swap files would be disabled. Then whenever you shut the machine down it would write through memory multiple times with all zeros, all ones and random data. The only thing on the disk would be the OS and encrypted files.

Just my 2p.

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Re : Brute force

Even if you possibly could run through all the combinations before the sun cooled you'd have to KNOW that you had cracked the encrypted info. Either a human search ! or some smart search algorithm.

So to be really safe double encrypt with 2 different keys

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