Encryption:
Technorati Tags: cryptography, public-key, encryption, RSA, asymmetric encryption The most successful public key cryptosystem in use today is RSA - named for its inventors Rivest, Shamir, and Adleman. I first learned about RSA in grad school from one of my...
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Posted on December 1, 2008 9:29 AM • 12 Comments •
I've been trying for a couple of weeks to put together a couple of interesting posts on the cryptographic modes of operation for confidentiality and integrity, and I just can't do it. I'm finding it boring to write about,...
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Posted on November 20, 2008 2:36 PM • 13 Comments •
In my last cryptography post, I wrote about using message authentication codes (MACs) as a way of guaranteeing message integrity. To review briefly, most ciphers are designed to provide message confidentiality - which means that no one but the...
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Posted on October 24, 2008 2:21 PM • 1 Comments •
Now, we're finally reaching the point where the block-cipher stuff gets really fun: block cryptanalysis. As I've explained before, the key properties of a really good encryption system are: It's easy to compute the ciphertext given the plaintext and...
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Posted on October 2, 2008 3:07 PM • 9 Comments •
So, as it turned out, I made a major screwup in my post earlier today on modes of operation. Rather than just edit the post, I'm adding a new post with the corrected description of the counter mode, and...
Posted on September 15, 2008 7:23 PM • 9 Comments •
Sorry for the slow pace of the blog lately. I've been sick with a horrible sinus infection for the last month, and I've also been particularly busy with work, which have left me with neither the time nor the...
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Posted on September 15, 2008 10:13 AM • 10 Comments •
As promised, now we're going to look at the first major block cipher: the DES. DES stands for "data encryption standard"; DES was the first encryption system standardized by the US government for official use. It's an excellent example...
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Posted on September 8, 2008 10:11 AM • 18 Comments •
Where encryption starts getting really interesting, in my opinion, is block ciphers. Block ciphers are a general category of ciphers that are sort of a combination of substitution and transposition ciphers, and sort of something entirely different. They're really...
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Posted on September 4, 2008 3:36 PM • 14 Comments •
The second major family of encryption techniques is called transposition ciphers. I find transposition ciphers to be rather dull; in their pure form, they're very simple, and not very difficult to crack, even without computers. But some of the...
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Posted on August 24, 2008 7:10 PM • 11 Comments •
To understand why serious encryption algorithms are so complex, and why it's so important to be careful with the critical secrets that make an encryption system work, it's useful to understand something about how people break encryption systems. The...
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Posted on August 15, 2008 9:01 AM • 14 Comments •
So, last time, we looked at simple substitution ciphers. In a substitution cipher, you take each letter, and pick a replacement for it. To encrypt a message, you just substitute the replacement for each instance of each letter. As...
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Posted on August 11, 2008 2:57 PM • 9 Comments •
The starting point talking about encryption is to understand what the point of it is; what it's supposed to do, what problems it's supposed to avoid. Encryption is fundamentally about communication: you've got two parties who want to communicate,...
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Posted on August 8, 2008 10:57 AM • 22 Comments •
As you've probably heard, the US customs service has, recently, asserted the right to confiscate any and all computers and/or digital storage carried by anyone crossing the US border. They further assert the right to demand all passwords, encryption...
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Posted on August 7, 2008 11:18 AM • 52 Comments •
