I concluded on the pruned .
Peter
Jim Schaad schreef op 2019-09-03 20:48:
> I have pruned and tossed in a few [JLS] comments.
>
> Jim
>
> FROM: Peter van der Stok <stokc...@bbhmail.nl>
> SENT: Tuesday, September 3, 2019 5:18 AM
> TO: Benjamin Kaduk <ka...@mit.edu>
> CC: Jim Schaad <i...@augustcellars.com>;
> draft-ietf-ace-coap-est....@ietf.org; consulta...@vanderstok.org; ace@ietf.org
> SUBJECT: Re: [Ace] AD review of draft-ietf-ace-coap-est-12 part 2
>
> Hi Ben,
>
> the last part of the responses to your thorough review.
> Apart from nits you found some "nice" mistakes.
>
> the openssl example make me worry a bit.
>
> See below.
>
> Peter
> _______________________________________________________________________
>
> SignedData is signed by the party that generated the private key,
> which may be the EST server or the EST CA. The SignedData is further
> protected by placing it inside of a CMS EnvelopedData as explained in
> Section 4.4.2 of [RFC7030]. In summary, the symmetrically encrypted
>
> .... if the SignedData is not the outermost container, then we don't care
> what the relevant Content-Format for it is; we only care about the
> Content-Format for the EnvelopedData.
>
> <pvds>
>
> s/ SignedData is signed/SignedData, placed in the outermost container, is
> signed/
>
> s/ The SignedData is further protected by placing it inside of a CMS
> EnvelopedData/
>
> SignedData placed within the Enveloped Data does not need additional signing/
>
> </pvds>
>
> Also, did we explicitly consider and reject AuthEnvelopedData?
>
> <pvds>
>
> Not sure about this
>
> [JLS] As a CMS person, I would consider the use of EnvelopedData and
> AuthEnvelopedData to be equivalent. Which of these is used is totally
> dependent on what algorithm is used for encryption. If one requires the use
> of AES-GCM or AES-CCM then one has no choice but to use AuthEnvelopedData.
> If one wants to use AES-CCM ten one has no choice but to use EnvelopedData.
> Everybody is slowly moving from EnvelopedData to AuthEnvelopedData just
> because everybody is changing algorithms. I do not remember any discussions
> about this, but AuthEnvelopeData is generally going to be the more correct
> value here. I will also note that there is a space between Enveloped and
> Data which is not CMS.
>
> <pvds2>
> I don't do anything here
> </pvds2>
>
> </pvds>
>
> encryptedKey attribute in a KeyTransRecipientInfo structure.
> Finally, if the asymmetric encryption key is suitable for key
> agreement, the generated private key is encrypted with a symmetric
> key which is encrypted by the client defined (in the CSR) asymmetric
>
> In the key-agreement case, the symmetric key-encryption key is the
> result of the key-agreement operation, no? In which case it is not
> itself encrypted, but rather the server's ephemeral public value is
> sent.
>
> <pvds>
>
> In RFC7030 the text says: the EnvelopedData content is encrypted using a
> randomly
>
> generated symmetric encryption key (that means ephemeral I assume). The
> cryptographic strength of
>
> the symmetric encryption key SHOULD be equivalent to the clientspecified
>
> asymmetric key.
>
> However, I see no explicit relation with the ephemeral public value.
>
> I don't know what to do here; probably insert the 7030 text.
>
> [JLS] Ben, you do not have the correct view of the key-agreement case. It
> does a key agreement -> KDF -> KeyWrap -> Content. There is always a key
> wrap step between the key agreement and the content encryption key.
> <pvds2>
> Also here I see no room for improvement then.
> <pvds2>
>
> </pvds>
>
> public key and is carried in an recipientEncryptedKeys attribute in a
> KeyAgreeRecipientInfo.
>
> [RFC7030] recommends the use of additional encryption of the returned
> private key. For the context of this specification, clients and
> servers that choose to support server-side key generation MUST
> support unprotected (PKCS#8) private keys (Content-Format 284).
> Symmetric or asymmetric encryption of the private key (CMS
> EnvelopedData, Content-Format 280) SHOULD be supported for
> deployments where end-to-end encryption needs to be provided between
> the client and a server. Such cases could include architectures
> where an entity between the client and the CA terminates the DTLS
> connection (Registrar in Figure 4).
>
> This carefully says nothing about recommendations for use, only for
> software support. Are we letting 7030's recommendation for use of
> encryption stand? It's probably worth being explicit, either way.
>
> <pvds> I did not find any recommendation for use in RFC7030 apart the
> responsibility of the server for generating random numbers. The
> recommendations at the top of section 5.8 of the draft seem adequate in my
> opinion. The alternative is classifying the applications; unless you see a
> better way to do this.
>
> </pvds>
>
> Why OPTIONAL? (Also, nit: OPTIONALLY isn't a 2119 keyword; only OPTIONAL.)
>
> client. For example, it could be configured to accept POP linking
> information that does not match the current TLS session because the
> authenticated EST client Registrar has verified this information when
> acting as an EST server.
>
> This is close enough to a literal quote that we might think about
> actually quoting and using quotation marks.
> nit: s/POP/PoP/ if we don't do the literal quote.
>
> <pvds>
>
> Hope my co-authors will react to this
>
> [JLS] I would disagree with the nit.
>
> [JLS] I would agree with the nit on OPTIONALLY being wrong, but I think that
> it ought to be at least a SHOULD if not a MUST for the use of COAPS as it is
> terminating the connection. The only exception would be in there is internal
> authentication for the EST request.
> <pvds2>
> Suggest to use SHOULD and not distinguish between terminating or not.
> <pvds2>
>
> </pvds>
>
> Section 9.1
>
> I think we probably need this document as a reference for all the
> allocations; as the document effectuating the registration, we are still
> of interest even if most details of content encoding lie elsewhere.
>
> [JLS] No response from Peter?
> <pvds2>
> Sorry, misunderstood. Will add <thisdocument>
> </pvds2>
>
> Appendix A.3
>
> I'm having trouble validating the private key in the PKCS#8 component:
> asn1parse says:
>
> <pvds>
>
> As input I used recently a hex dump of Wt1234.key.der:
>
> 308187020100301306072a8648ce3d020106082a8648ce3d030107046d30
> 6b020101042061336a86ac6e7af4a96f632830ad4e6aa0837679206094d7
> 679a01ca8c6f0c37a14403420004c8b421f11c25e47e3ac57123bf2d9fdc
> 494f028bc351cc80c03f150bf50cff958d75419d81a6a245dffae790be95
> cf75f602f9152618f816a2b23b5638e59fd9
>
> I used openssl pkey -in Wt1234.key.der -text -noout -inform der\
>
> -passin pass:watnietweet
>
> [JLS] I would lose the password on the key if possible.
>
> <pvds2>
> Right, It means changing the whole chain of certificates. and redoing the
> examples.
> But I understand the reason, being confronted with the disassembly failure.
> </pvds2>
>
> The password is may be prohibitive?
>
> Resulting in:
> Private-Key: (256 bit)
> priv:
> 61:33:6a:86:ac:6e:7a:f4:a9:6f:63:28:30:ad:4e:
> 6a:a0:83:76:79:20:60:94:d7:67:9a:01:ca:8c:6f:
> 0c:37
> pub:
> 04:c8:b4:21:f1:1c:25:e4:7e:3a:c5:71:23:bf:2d:
> 9f:dc:49:4f:02:8b:c3:51:cc:80:c0:3f:15:0b:f5:
> 0c:ff:95:8d:75:41:9d:81:a6:a2:45:df:fa:e7:90:
> be:95:cf:75:f6:02:f9:15:26:18:f8:16:a2:b2:3b:
> 56:38:e5:9f:d9
> ASN1 OID: prime256v1
> NIST CURVE: P-256
>
> $ unhex|openssl asn1parse -inform der
> 308187020100301306072a8648ce3d020106082a8648ce3d030107046d30
> 6b02010104200b9a67785b65e07360b6d28cfc1d3f3925c0755799deeca7
> 45372b01697bd8a6a144034200041bb8c1117896f98e4506c03d70efbe82
> 0d8e38ea97e9d65d52c8460c5852c51dd89a61370a2843760fc859799d78
> cd33f3c1846e304f1717f8123f1a284cc99f
> 0:d=0 hl=3 l= 135 cons: SEQUENCE
> 3:d=1 hl=2 l= 1 prim: INTEGER :00
> 6:d=1 hl=2 l= 19 cons: SEQUENCE
> 8:d=2 hl=2 l= 7 prim: OBJECT :id-ecPublicKey
> 17:d=2 hl=2 l= 8 prim: OBJECT :prime256v1
> 27:d=1 hl=2 l= 109 prim: OCTET STRING [HEX
> DUMP]:306B02010104200B9A67785B65E07360B6D28CFC1D3F3925C0755799DEECA745372B01697BD8A6A144034200041BB8C1117896F98E4506C03D70EFBE820D8E38EA97E9D65D52C8460C5852C51DD89A61370A2843760FC859799D78CD33F3C1846E304F1717F8123F1A284CC99F
>
> which doesn't look like an RFC5208 PrivateKeyInfo:
>
> PrivateKeyInfo ::= SEQUENCE {
> version Version,
> privateKeyAlgorithm PrivateKeyAlgorithmIdentifier,
> privateKey PrivateKey,
> attributes [0] IMPLICIT Attributes OPTIONAL }
>
> Version ::= INTEGER
>
> PrivateKeyAlgorithmIdentifier ::= AlgorithmIdentifier
>
> PrivateKey ::= OCTET STRING
>
> Attributes ::= SET OF Attribute
>
> due to the lack of OID for privateKeyAlgorithm, etc.
> (`openssl pkcs8` also chokes on it, but I don't have a working example and
> can't rule out user error there.)
>
> Even that giant OCTET STRING 27 bytes in doesn't seem to match a
> PrivateKeyInfo:
>
> $ unhex|openssl asn1parse -inform der -strparse 27
> 308187020100301306072a8648ce3d020106082a8648ce3d030107046d30
> 6b02010104200b9a67785b65e07360b6d28cfc1d3f3925c0755799deeca7
> 45372b01697bd8a6a144034200041bb8c1117896f98e4506c03d70efbe82
> 0d8e38ea97e9d65d52c8460c5852c51dd89a61370a2843760fc859799d78
> cd33f3c1846e304f1717f8123f1a284cc99f
> 0:d=0 hl=2 l= 107 cons: SEQUENCE
> 2:d=1 hl=2 l= 1 prim: INTEGER :01
> 5:d=1 hl=2 l= 32 prim: OCTET STRING [HEX
> DUMP]:0B9A67785B65E07360B6D28CFC1D3F3925C0755799DEECA745372B01697BD8A6
> 39:d=1 hl=2 l= 68 cons: cont [ 1 ]
> 41:d=2 hl=2 l= 66 prim: BIT STRING
>
> though the OCTET STRING does have the private key and the BIT STRING has
> the public key's contents as depicted in C.3 (details of that too boring
> to show).
>
> So I have to wonder if I'm messing something up, somewhere.
>
> Appendix B.1
>
> Should we be using the same Token value in two different exchanges in
> this document?
>
> <pvds>
>
> No opinion
>
> [JLS] As long as the Token values are not in the same exchange, this makes no
> difference. Tokens are reused after an amount of time in CoAP.
>
> <pvds2>
> No extra text, I gather
> </pvds2>
>
> </pvds>
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