Is less about what is deprecated and more about what HW support is
available on already deployed solutions.

On 18 May 2017 at 10:27, Peltonen, Janne (Nokia - FI/Espoo)
<[email protected]> wrote:
> Hi,
>
> The IPsec and IKE document roadmap (RFC 6071) is a good summary about
> the required crypto-algorithms, among other things.
>
> Bill Fischofer wrote:
>> On Wed, May 17, 2017 at 7:07 PM, Dmitry Eremin-Solenikov <
>> [email protected]> wrote:
>>
>> > I think, linux-generic should support the following algorihms:
>> >
>> > Cipher:
>> >
>> > - AES-CBC (MUST)
>> > - AES-CTR (MAY)
>> > - 3DES-CBC (MAY)
>> >
>>
>> 3DES appears to be nearing end of life, especially with the recent sweet32
>> [1] attacks so this may be more of a "nice to have", though I see no harm
>> in including it for compatibility. I doubt if many new ODP applications
>> would use 3DES in preference to AES at this point.
>>
>
> 3DES-CBC is still mandatory in IPsec so it is good to keep it.
>
> And besides that, new ODP applications may have to interoperate with
> other systems in existing network deployments that may still use some
> of the older algorithms. I think the benefit of removing an existing
> algorithm implementation is small compared to the trouble it could
> cause in these cases.
>
>> >
>> > Auth:
>> >
>> > - HMAC-SHA1 (MUST)
>> > - HMAC-SHA256/384/512 (optional)
>> > - HMAC-MD5 (unspecified, was MAY)
>> >
>>
>> MD5 is already deprecated [2], and SHA-1 doesn't seem to have long to live
>> either [2]. Enough people still use SHA-1 that it seems we should support
>> it but I think it is safe to drop MD5 support at this point.
>
> HMAC-MD5-96 is optional (MAY) and HMAC-SHA-1-96 is mandatory (MUST) in IPsec.
> The weaknesses of MD5 used as a hash do not necessarily affect HMAC-MD5.
> See RFC 4835, RFC 6151.
>
> The point about interoperability also applies.
>
>         Janne
>
>> [1] https://www.openssl.org/blog/blog/2016/08/24/sweet32/
>> [2] https://www.nsrl.nist.gov/collision.html
>> [3] http://csrc.nist.gov/groups/ST/hash/policy.html

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