Re: [Lwip] Review of draft-ietf-lwig-minimal-esp-00

[Daniel Migault <[e-mail]>]

Hi Tero,

Thanks for the comments. Please find below how I updated the text on my
local copy and let me know if that addresses your concerns.

Yours,
Daniel

On Fri, Oct 30, 2020 at 3:26 PM Tero Kivinen <[e-mail]> wrote:

> Daniel Migault writes:
> >    value SN needs to be considered instead.  Note that the limit of
> >    messages being sent is primary determined by the security associated
> >    to the key rather than the SN.  The security of the key used to
> >    encrypt decreases with the each message being sent and a node MUST
> >    ensure the limit is not reached - even though the SN would permit it.
> >    In a constrained environment, it is likely that the implementation of
> a
> >    rekey mechanism is preferred over the use of ESN.
>
> No. The security of the key does not decrease, but the ability for the
> attacker to attack the key might incrase, and the value of attacking
> that one key also increases when more data is encrypted with it. Also
> with short block length algorithms there were stricter limits of data
> that can be encrypted with one key.
>
<mglt>
Thanks. Here is the text I propose.
The security of all data protected under a given key decreases slightly
with each message and a node MUST ensure the limit is not reached - even
though the SN would permit it.
</mglt>

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-- 
Daniel Migault
Ericsson