Re: [TLS] HSM-friendly Key Computation
Martin Thomson <martin.thomson@gmail.com> Fri, 17 April 2015 19:45 UTC
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Date: Fri, 17 Apr 2015 12:44:59 -0700
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From: Martin Thomson <martin.thomson@gmail.com>
To: Eric Rescorla <ekr@rtfm.com>
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Cc: IETF TLS <tls@ietf.org>
Subject: Re: [TLS] HSM-friendly Key Computation
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Note also that this is a known issue. Mike StJohns raised it previously. https://github.com/tlswg/tls13-spec/issues/5 On 17 April 2015 at 12:40, Eric Rescorla <ekr@rtfm.com> wrote: > We should defer this issue until we know whether we are generating an IV > at all. > > -Ekr > > > On Fri, Apr 17, 2015 at 11:59 AM, Russ Housley <housley@vigilsec.com> wrote: >> >> Section 6.3 of draft-ietf-tls-tls13-05 describes the key calculation from >> the current master secret (MS). First a key block is computed: >> >> key_block = PRF(MS, >> "key expansion", >> SecurityParameters.server_random + >> SecurityParameters.client_random); >> >> Then, the key block is divided into keys and IVs: >> >> client_write_key[SecurityParameters.enc_key_length] >> server_write_key[SecurityParameters.enc_key_length] >> client_write_IV[SecurityParameters.fixed_iv_length] >> server_write_IV[SecurityParameters.fixed_iv_length] >> >> If one wants to implement the cryptographic functions in a Hardware >> Security Module (HSM), this structure is far from ideal. In general I would >> expect the client_write_key and server_write_key to stay inside the >> protected boundary of the HSM, but the client_write_IV and server_write_IV >> do not need this protection. Both of these coming from the same key_block >> makes this separation very difficult to implement. >> >> Can we get these values from different invocations of the PRF? I'd like >> to see one invocation for values that are expected to remain secret and a >> separate invocation for values that do not need to remain secret. >> >> Russ >> >> _______________________________________________ >> TLS mailing list >> TLS@ietf.org >> https://www.ietf.org/mailman/listinfo/tls > > > > _______________________________________________ > TLS mailing list > TLS@ietf.org > https://www.ietf.org/mailman/listinfo/tls >
- [TLS] HSM-friendly Key Computation Russ Housley
- Re: [TLS] HSM-friendly Key Computation Eric Rescorla
- Re: [TLS] HSM-friendly Key Computation Martin Thomson
- Re: [TLS] HSM-friendly Key Computation Ilari Liusvaara
- Re: [TLS] HSM-friendly Key Computation Yoav Nir
- Re: [TLS] HSM-friendly Key Computation Brian Smith
- Re: [TLS] HSM-friendly Key Computation Eric Rescorla
- Re: [TLS] HSM-friendly Key Computation Peter Gutmann
- Re: [TLS] HSM-friendly Key Computation Benjamin Beurdouche
- Re: [TLS] HSM-friendly Key Computation Michael StJohns
- Re: [TLS] HSM-friendly Key Computation Ilari Liusvaara
- Re: [TLS] HSM-friendly Key Computation StJohns, Michael
- Re: [TLS] HSM-friendly Key Computation Ilari Liusvaara
- Re: [TLS] HSM-friendly Key Computation Robert Relyea
- Re: [TLS] HSM-friendly Key Computation Ilari Liusvaara
- Re: [TLS] HSM-friendly Key Computation Eric Rescorla
- Re: [TLS] HSM-friendly Key Computation Michael StJohns
- Re: [TLS] HSM-friendly Key Computation Eric Rescorla
- Re: [TLS] HSM-friendly Key Computation Ilari Liusvaara
- Re: [TLS] HSM-friendly Key Computation Eric Rescorla
- Re: [TLS] HSM-friendly Key Computation Ilari Liusvaara
- Re: [TLS] HSM-friendly Key Computation Michael StJohns
- Re: [TLS] HSM-friendly Key Computation Michael StJohns
- Re: [TLS] HSM-friendly Key Computation Ilari Liusvaara
- Re: [TLS] HSM-friendly Key Computation Michael StJohns
- Re: [TLS] HSM-friendly Key Computation Eric Rescorla
- Re: [TLS] HSM-friendly Key Computation Eric Rescorla
- Re: [TLS] HSM-friendly Key Computation Ilari Liusvaara
- Re: [TLS] HSM-friendly Key Computation Joseph Salowey
- Re: [TLS] HSM-friendly Key Computation Watson Ladd
- Re: [TLS] HSM-friendly Key Computation Ilari Liusvaara
- Re: [TLS] HSM-friendly Key Computation Hugo Krawczyk