cryptography – Tales from the bits

Quantum Cryptography Breached With Lasers

George Bagropoulos — Sat, 18 Sep 2010 08:06:09 +0000

Up until recently quantum cryptography thought to be secure to transmit cryptographic keys. Any attempt to eavesdrop the transmission could be easily detected (based on Heisenberg uncertainty principle). This was proved wrong by the team of researchers from the Norwegian University of Science and Technology (NTNU), the University of Erlangen-Nürnberg and the Max Planck Institute for the Science of Light in Erlangen. The team developed a quantum eavesdropping technique that remotely controls the photon detector. The researchers wrote that someone “can attack the systems with off-the-shelf components, obtaining a perfect copy of the raw key without leaving any trace of her presence.”

Vadim Makarov, one of the researchers, said that “The security loophole we have exposed is intrinsic to a whole class of single-photon detectors, regardless of their manufacturer and model.”

BitLocker or TrueCrypt?

George Bagropoulos — Sun, 10 Jan 2010 14:40:25 +0000

(Last updated May 31 ,2014)

Latest update: Truecrypt Shut Down. The sourceforge page informs Truecrypt users to migrate any data encrypted by TrueCrypt to encrypted disks or virtual disk images supported on your platform.

BitLocker and TrueCrypt are data encryption software packages. The question is which one to use and why? BitLocker comes with Windows 7 Ultimate edition. It is also available in Windows 8.1 Pro, Windows 8.1 Enterprise editions and Windows Server 2012 R2. TrueCrypt is free open source software. As of this last update, TrueCrypt does not support Windows 8. You can find the supported operating systems here.

Michael Pietroforte at 4SYSOPS has two very interesting articles. In the first article he comparesTrueCrypt 5 vs. Bitlocker. There are no significant speed differences between the two programs. The second article is a discussion about Windows 7 BitLocker. Good news is that with Windows 7 using BitLocker is much easier comparing with Windows Vista.

With BitLocker if your computer does not have a Trusted Platform Module chip the start up key in a USB stick. On the other hand TrueCrypt wants to only to memorize a pass phrase.

Which one to use?

BitLocker:

Can be used in a whole Windows environment
Allows storage of startup key in USB stick
Allows IT Administrators to enforce Group policy

TrueCrypt:

Can be used with many operating systems including Microsoft and Linux
It is free and open source.
It does not require to store a start up key to any device. You must remember the pass phrase. Of course you can store your pass phrase in any storage media at your own risk.

From the above discussion, I believe that for large corporations the preferred solution would be BitLocker. For smaller businesses or for your personal computer or laptop TrueCrypt offers a really great solution.

For the security perspective there is the ‘Evil Maid’ attack that can be used to TrueCrypt to acquire the pass phrase. BitLocker uses trusted boot that can be attacked too. So, what is the ‘Evil Maid’ attack? In a nutshell the attack is as follows:

You leave your laptop into your hotel room and you go for breakfast.
An evil maid (enemy) enters your room and changes the boot-loader.
Next time you will operate your computer and enter your key it will be transmitted to the eavesdropper.

The attack, along with the software is explained by Joanna Rutkowska. There is also a very interesting discussion about “Evil Maid’ in Bruce Schneier’s blog.

As a conclusion, both BitLocker and TrueCrypt are excellent programs that can encrypt data. Now that you know the pros and cons of the programs and also the attack methods I hope it is easier to select the appropriate one for your needs.

My personal preference is TrueCrypt for the simple reason that is open source. Being open source makes it very difficult to add a backdoor. The code is visible, anyone can spot it. This might not be the same with commercial products.

(Update April 2014) US consultancy iSEC has completed on April 2014 a detailed two – person code audit of the software seeking security holes. The audit has turned up a dozen bugs in the code that is TrueCrypt, but not signs of backdoors or other critical security holes. You can access the full report in pdf fprmat here.

GSM A5/1 Encryption cracked.

George Bagropoulos — Wed, 06 Jan 2010 14:03:25 +0000

Ellinor Millshas an interesting interview with German security expert Karsten Nohl, who showed at the Chaos Communication Congress how easy is to eavesdrop GSM calls. Nohl says that GSM’s A5/1 encryption function uses a 64-bit key that is too short to withstand the computing power available today. When the algorithm was designed 20 years ago when CPU [central processing unit] cycles and storage were much more expensive, it must have seemed a lot more secure. However, the A5/1 function should have been replaced years ago when researchers first discussed practical attacks.

Is there hope? Yes, but not for the time beeing. The GSM opearators have to switch to A5/3. A much stronger algorithm which for the time beeing is secure.

My comment: Do not say things over your mobile phone that you do not want someone to hear.

Quantum Cryptography Cracked

George Bagropoulos — Thu, 31 Dec 2009 18:23:00 +0000

Quantum cryptography was thought to be much more secure than all classical cryptography schemes.
This extremely interesting presentation shows a successful attack of an existing quantum key distribution system exploiting a photon detector vulnerability which is probably present in all existing devices. Without Alice and Bob losing their faith in their secure communication, the group recorded 100% of the supposedly secret key.

I have a great interest in quantum cryptography. The above presentation proves another technological assumption wrong.

Breakthrough in quantum cryptography

George Bagropoulos — Tue, 05 May 2009 06:57:00 +0000

(Source: PhysOrg.com) A team from Austria’s Institute for Quantum Optics and Quantum Information (IQOQI) managed to send entangled photons 144 kilometres (90 miles) between the Spanish islands of Las Palmas and the Balearics using satellites
Quantum cryptography is possible over a modern glass fibre net, but because of the high rate of transmission loss, this is limited to around 100 km. To realise future quantum communication networks on a global scale, satellite based systems must be developed and photons transmitted over optical free space distant from the ground.

More information:
http://www.nature.com/nphys/journal/vaop/ncurrent/abs/nphys1255.html