Re: [Cfrg] the "tradition" of powers of 2

Watson Ladd <watsonbladd@gmail.com> Tue, 04 November 2014 16:44 UTC

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Date: Tue, 04 Nov 2014 08:44:12 -0800
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From: Watson Ladd <watsonbladd@gmail.com>
To: Phillip Hallam-Baker <phill@hallambaker.com>
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Subject: Re: [Cfrg] the "tradition" of powers of 2
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On Tue, Nov 4, 2014 at 8:24 AM, Phillip Hallam-Baker
<phill@hallambaker.com> wrote:
> And which of these choices did the community adopt widely?
> c
> AES 128
> AES 256
> RSA 512
> RSA 1024
> RSA 2408
> RSA 4096
> MD5 (128 bits)
> SHA1 (160 bits)
> SHA-2 (256 / 512 bits)
>
> The only choice not a power of 2 that was widely used is SHA-1 at
> 160Bits. But that was largely chosen by default after MD5 was found
> wanting.

Wrong: Triple-DES was and is used widely in banking. Binary curves are
used widely in hardware.

>
> Use of RSA1280 is limited to DNSSEC which has very peculiar limitations.
>
>
> Yes, lots of folk have tried lots of different key sizes over the
> years. But thats not the point. The point is which key sizes have
> become ubiquitous choices.