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Re: IBM's patented algorithm



Ran Atkinson says:
>   There is community consensus behind DES CBC, which has been long
> analysed in the public and has no patent issues.

But it has exportability issues. You choose the problem you're comfortable
with: no-export, or patent concerns.

If you take 56-bit key, weaken it down to 40 bits, then expand it again
to 56 bits and feed it to DES - you got CDMF...

> I don't believe
> that any proprietary algorithm would be a good choice as a mandatory
> to implement algorithm.

CDMF is essentially DES with known strength. To say it "proprietary" sounds
more like a name-calling. It's less "proprietary" than RSA, for example. At
least here you can get some free commercial usage (:-).

> I personally find the IBM license terms that you describe to be onerous.

We [technical people in IBM] are fighting to make it royalty-free. The
lawyers [so far] don't agree. What I described was the best we could
get from them [till now]. The battle continues.

But personally - I don't think it's too onerous to say: "You can use my
patent free, if you allow me to use yours (unless you have no patent,in
which case just use mine)".
--
Regards,
Uri         uri@watson.ibm.com      N2RIU
===========
<Disclamer>



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