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Archive for 'crypto'

Zcipher Algorithm

Zcipher is a symmetric encryption algorithm made by me few years ago. It is a 64-bit block cipher with a 128-bit key. Zcipher is unpatented and public domain. Please note that it is a toy cipher, not a serious replacement for AES, Twofish, RC6, etc.
Here are

Algorithm specification (pdf, 54kb)
zcipher.c - reference implementation in C […]

A byte-oriented AES-256 implementation

As you may know, I do cryptographic perversions occasionally. Recently I’ve been asked for a compact implementation of AES-256. Code size must be as small as possible, speed is not important and (here is the catch) no assembler. The requesters have tried various public available implementations before, none were fit. So I did mine. It […]

T-functions Testbed

During last year I’ve seen few submission papers that are based on my note about singe cycle functions. The latest such paper puzzled me. The authors have reconstructed theory quite well but at some point have jumped surprisingly to a premature and wrong conclusion. To make things simpler, I’ve sketched a small online tool to […]

Cipher DAGs

When I wrote “I also have picked up couple interesting thoughts during Raffael Marty’s talk on Insider Threat Visualization“, I meant something like this work by Daniel J. Bernstein on tools to diagram cryptographic algorithms (pdf, 523kb) So, I do not need to do it myself. Nice. Looking forward for public release of cipherdag package.
Thanks […]

Undocumented Windows cryptography

The last time we described semi- and undocumented functions in Windows, these were compression functions. Today’s subject is cryptographic functions. There are such functions in Windows core that allows you to use few cryptographic primitives easier, without whole CAPI overhead and hassle. Here is an example of how to generate secure random numbers and calculate […]