National Semiconductor 48-bit and 56-bit ECC polynomials

[Al Kossow]

you might also look at patent 4979173

cirrus / adaptec from around that time

x^52 + x^50 + x^43 + x^41 + x^34 + x^30 + x^26 + x^24 + x^8 +1

licensed from Glover

On 11/18/16 3:02 PM, David Gesswein wrote:
> On Thu, Nov 17, 2016 at 03:33:36PM -0700, Eric Smith wrote:
>> I'm not looking forward to trying to reverse-engineer 48-bit and 56-bit ECC
>> polynomials. However, they usually tried to choose polynomials with
>> relatively few terms, to minimize the number of XOR gates needed in the
>> hardware.
>>
> ...
>> There might be some other short-cuts to reducing the search space, but I
>> haven't yet given it a lot of thought.
>>
>>
> I haven't run across it yet. If they used it for the header it is easy to
> reverse since they naturally have a pattern that is easy to calculate the
> polynomial from. You may find sector data with the correct pattern to also 
> use the method.
> 
> http://www.cosc.canterbury.ac.nz/greg.ewing/essays/CRC-Reverse-Engineering.html
>