Entries Tagged "encryption"

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Password Safe

Password Safe is a free Windows password-storage utility. These days, anyone who is on the Web regularly needs too many passwords, and it’s impossible to remember them all. I have long advocated writing them all down on a piece of paper and putting it in your wallet.

I designed Password Safe as another solution. It’s a small program that encrypts all of your passwords using one passphrase. The program is easy to use, and isn’t bogged down by lots of unnecessary features. Security through simplicity.

Password Safe 2.11 is now available.

Currently, Password Safe is an open source project at SourceForge, and is run by Rony Shapiro. Thank you to him and to all the other programmers who worked on the project.

Note that my Password Safe is not the same as this, this, this, or this PasswordSafe. (I should have picked a more obscure name for the program.)

It is the same as this, for the PocketPC.

Posted on June 15, 2005 at 1:35 PMView Comments

Eric Schmidt on Secrecy and Security

From Information Week:

InformationWeek: What about security? Have you been paying as much attention to security as, say Microsoft—you can debate whether or not they’ve been successful, but they’ve poured a lot of resources into it.

Schmidt: More people to a bad architecture does not necessarily make a more secure system. Why don’t you define security so I can answer your question better?

InformationWeek: I suppose it’s an issue of making the technology transparent enough that people can deploy it with confidence.

Schmidt: Transparency is not necessarily the only way you achieve security. For example, part of the encryption algorithms are not typically made available to the open source community, because you don’t want people discovering flaws in the encryption.

Actually, he’s wrong. Everything about an encryption algorithm should always be made available to everyone, because otherwise you’ll invariably have exploitable flaws in your encryption.

My essay on the topic is here.

Posted on May 31, 2005 at 1:09 PMView Comments

Holding Computer Files Hostage

This one has been predicted for years. Someone breaks into your network, encrypts your data files, and then demands a ransom to hand over the key.

I don’t know how the attackers did it, but below is probably the best way. A worm could be programmed to do it.

1. Break into a computer.

2. Generate a random 256-bit file-encryption key.

3. Encrypt the file-encryption key with a common RSA public key.

4. Encrypt data files with the file-encryption key.

5. Wipe data files and file-encryption key.

6. Wipe all free space on the drive.

7. Output a file containing the RSA-encrypted, file encryption key.

8. Demand ransom.

9. Receive ransom.

10. Receive encrypted file-encryption key.

11. Decrypt it and send it back.

In any situation like this, step 9 is the hardest. It’s where you’re most likely to get caught. I don’t know much about anonymous money transfer, but I don’t think Swiss bank accounts have the anonymity they used to.

You also might have to prove that you can decrypt the data, so an easy modification is to encrypt a piece of the data with another file-encryption key so you can prove to the victim that you have the RSA private key.

Internet attacks have changed over the last couple of years. They’re no longer about hackers. They’re about criminals. And we should expect to see more of this sort of thing in the future.

Posted on May 30, 2005 at 8:18 AMView Comments

AES Timing Attack

Nice timing attack against AES.

For those of you who don’t know, timing attacks are an example of side-channel cryptanalysis: cryptanalysis using additional information about the inner workings of the cryptographic algorithm. I wrote about them here.

What’s the big idea here?

There are two ways to look at a cryptographic primitive: block cipher, digital signature function, whatever. The first is as a chunk of math. The second is a physical (or software) implementation of that math.

Traditionally, cryptanalysis has been directed solely against the math. Differential and linear cryptanalysis are good examples of this: high-powered mathematical tools that can be used to break different block ciphers.

On the other hand, timing attacks, power analysis, and fault analysis all makes assumptions about implementation, and uses additional information garnered from attacking those implementations. Failure analysis assumes a one-bit feedback from the implementation — was the message successfully decrypted — in order to break the underlying cryptographic primitive. Timing attacks assumes that an attacker knows how long a particular encryption operation takes.

Posted on May 17, 2005 at 10:05 AMView Comments

RFID Passport Security

According to a Wired article, the State Department is reconsidering a security measure to protect privacy that it previously rejected.

The solution would require an RFID reader to provide a key or password before it could read data embedded on an RFID passport’s chip. It would also encrypt data as it’s transmitted from the chip to a reader so that no one could read the data if they intercepted it in transit.

The devil is in the details, but this is a great idea. It means that only readers that know a secret data string can query the RFID chip inside the passport. Of course, this is a systemwide global secret and will be in the hands of every country, but it’s still a great idea.

It’s nice to read that the State Department is taking privacy concerns seriously.

Frank Moss, deputy assistant secretary for passport services, told Wired News on Monday that the government was “taking a very serious look” at the privacy solution in light of the 2,400-plus comments the department received about the e-passport rule and concerns expressed last week in Seattle by
participants at the Computers, Freedom and Privacy conference. Moss said recent work on the passports conducted with the National Institute of Standards and Technology had also led him to rethink the issue.

“Basically what changed my mind was a recognition that the read rates may have actually been able to be more than 10 centimeters, and also recognition that we had to do everything possible to protect the security of people,” Moss said.

The next step is for them to actually implement this countermeasure, and not just consider it. And the step after that is for us to get our hands on some test passports to see if they’ve implemented it well.

Posted on April 28, 2005 at 8:30 AMView Comments

The Doghouse: ExeShield

Yes, there are companies that believe that keeping cryptographic algorithms secret makes them more secure.

ExeShield uses the latest advances in software protection and encryption technology, to give your applications even more protection. Of course, for your security and ours, we won’t divulge the encryption scheme to anyone.

If anyone reading this needs a refresher on exactly why secret cryptography algorithms are invariably snake oil, I wrote about it three years ago.

Posted on April 13, 2005 at 9:19 AMView Comments

The Doghouse: Xavety

It’s been a long time since I doghoused any encryption products. CHADSEA (Chaotic Digital Signature, Encryption, and Authentication) isn’t as funny as some of the others, but it’s no less deserving.

Read their “Testing the Encryption Algorithm” section: “In order to test the reliability and statistical independency of the encryption, several different tests were performed, like signal-noise tests, the ENT test suite (Walker, 1998), and the NIST Statistical Test Suite (Ruhkin et al., 2001). These tests are quite comprehensive, so the description of these tests are subject of separate publications, which are also available on this website. Please, see the respective links.”

Yep. All they did to show that their algorithm was secure was a bunch of statistical tests. Snake oil for sure.

Posted on March 15, 2005 at 11:00 AMView Comments

Sidebar photo of Bruce Schneier by Joe MacInnis.