VCR Controller Code

A while ago, Curt Welch, Andy Kinsman, and I determined most of the algorithm used by the VCRPlus controller, and published an academic paper on this. Click for the text of the paper, Figure 1, Figure 2, or in pdf. (Note that there's a typo in figure 1, where the input to box 6 should be c5c4c3c2c1c0. There's also a typo in example 2, where top 28 should be top 66.) Some history is on Curt Welch's web page.

The citation for the paper is:

K. Shirriff, C. Welch, A. Kinsman, Decoding a VCR Controller Code, Cryptologia, 16(3), July 1992, pp 227-234.

We haven't done any more research on the 7 and 8 digit codes, nor are we aware of anyone else who has. The algorithm we published can be considerably simplified, and I have some incomprehensible rough notes on how to do this and where the key comes from.

New:

Ken Shirriff: [email protected]