Cryptosmith

Cyber and security architecture, not bitcoins

Security

Homework

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Pragmatic Security: the history of the Visa card

I’ve been looking at the evolution of electronic funds transfer (EFT) and payment systems recently. My…
Boak’s Puzzle: Disposing of Classified Trash

Recently I was skimming through the NSA’s “classified history of COMSEC” (Volume 1 and Volume 2). This…
Real-world document encryption

I’ve been reviewing histories of cryptography recently and here’s an interesting thing about pre-computer encryption: it’s…
Design Patterns for Identity Systems

These are design patterns in the Christopher Alexander sense rather than the object oriented design sense:…
Fixing the Insider Threat: Separation of Duty

The insider threat isn’t easy to fix. We can fix it with Separation of Duty, but…
Stream Cipher Reuse: A Graphic Example

Take a look at the following image. You should see two different ‘messages’ here. This particular…
One-Time Pads

The one-time pad is the only encryption technique that has been mathematically proven to be uncrackable.…
Encrypting with XOR: A Graphic Example

The exclusive or operation – a logical function applied to binary bits, like AND, OR, and…
Stream ciphers

Whenever your browser establishes a “secure” connection to a web site, it encrypts the data. The…