The Serpent Cipher’s Key Schedule Transform is Injective.

This article is a continuation of the previous, and concludes the series.

Let’s try this somewhat different variant of the program, which represents recurring bits of the expansion symbolically (and in a slightly more readable form) [...]

The Serpent Cipher’s Key Schedule Equation System, in Graphical Form.

This article is a continuation of the dig into the key schedule of the Serpent cipher.

For clarity, we will omit the routines already given in the previous article.

Let’s visualize the Serpent [...]

Serpent Cipher’s Key Schedule in Algebraic Form: with Reduction.

This article is a continuation of the recent mega-puzzler concerning the experiment.

This variant will reduce the equations. We will omit printing the input matrix, for brevity. And so:

;; Register bitness.
(defconstant +bitness+ 32)
 
(defun flatten (l)
[...]

Terms -8…8 of the Serpent Cipher’s Key Schedule in Algebraic Form.

This article is a byproduct of the recent mega-puzzler concerning the Serpent cipher’s key expansion procedure.

Behold:

;; Register bitness.
(defconstant +bitness+ 32)
 
(defun make-reg (reg-name bitness)
"Make algebraic representation of a register (bits in descending majority)"
(loop for i from [...]

The Alert Reader.

The following is a conversation I recently had with an alert and inquisitive reader. It has been redacted for brevity; handles/names/irrelevant things have been removed. Some text has been turned into links to relevant material.
Anyone still reading this page for reasons related to its original purpose is encouraged to read this; it may help to [...]

Kalman Reti, the Last Symbolics Developer, Speaks of Lisp Machines.

Boston Lisp Meeting; June 28, 2012.
Update: Here’s a mirror of the film. The Google copy appears to have been censored.

Project JMC

The great inventor John McCarthy (1927 – 2011) now has an official posthumous website: Project JMC.
Don’t miss his fascinating (though little-known) political essays!

The curious incident of the Lisp in the night-time

Gregory (Scotland Yard detective): “Is there any other point to which you would wish to draw my attention?”
Holmes: “To the curious incident of the dog in the night-time.”
Gregory: “The dog did nothing in the night-time.”
Holmes: “That was the curious incident.”
- “Silver Blaze” (Sir Arthur Conan Doyle)
Yesterday, I heard a lecture by David M. Baggett, a [...]

Posted in: Distractions, Hot Air, Lisp, NonLoper by Stanislav 11 Comments

Stierlitz Example: Memory-Mapped I/O to a Character LCD

Here is a somewhat dumb example of the kind of thing one can do with Stierlitz.  Let’s say that you have some memory-mapped I/O ports in your system architecture, which you would like to test without having a working CPU design of any kind loaded into your FPGA.
The Xilinx ML501 board includes a Tianma-TM162, which [...]

Posted in: Cold Air, FPGA, Hardware, Lisp, LoperOS by Stanislav 4 Comments

Stierlitz, the Fearless, Driver-Less Bus Analyzer.

The tool described in this post may be helpful to other ab initio machine-architecture developers.  If any exist.  The rest of Loper will remain in my private code repository, because it is not a collaborative project.
Meet Stierlitz [1], perhaps the world’s strangest bus analyzer.  For basic use, it requires no software at all on the [...]

Posted in: Cold Air, FPGA, Hardware, Lisp, LoperOS, Progress by Stanislav 2 Comments
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