Re: [TLS] HSM-friendly Key Computation

Peter Gutmann <> Sun, 19 April 2015 04:23 UTC

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From: Peter Gutmann <>
To: Russ Housley <>, IETF TLS <>
Thread-Topic: [TLS] HSM-friendly Key Computation
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Date: Sun, 19 Apr 2015 04:22:59 +0000
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Subject: Re: [TLS] HSM-friendly Key Computation
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Russ Housley <> writes:

>If one wants to implement the cryptographic functions in a Hardware Security
>Module (HSM), this structure is far from ideal.

Weelll... it's far from ideal if you want to use traditional/historic PKCS #11
mechanisms, but since a new PRF will need updated HSM support anyway it
shouldn't be any problem to accommodate it, and now that PKCS #11 is being
managed by OASIS rather than RSADSI/EMC and things have got moving again in
advancing the spec, it shouldn't be that big a deal.  If you look at how
CKM_TLS_PRF works, it's a significant change from how C_DeriveKey() normally
functions that was made in order to accommodate how TLS wants to do things.
For the TLS 2.0 (a.k.a. 1.3) PRF the PKCS #11 folks can make the same
accommodation.  It's an issue for the HSM vendors to adapt, not the TLS spec
to adapt.