Re: [auth48] AUTH48: RFC-to-be 9474 <draft-irtf-cfrg-rsa-blind-signatures-14> for your review

[Sandy Ginoza <[e-mail]>]

Hi Chris,

> On Sep 19, 2023, at 7:03 AM, Christopher Wood <[e-mail]> wrote:
> 
> Before digging into this, is there a reason we can’t do this AUTH48 via GitHub? I find it quite cumbersome (and error prone) to carry this out over email. GitHub gives us the added benefit of letting others follow along in the process.

Unfortunately, it is too late to transition this AUTH48 to GitHub.  In the future, please request a GitHub experiment soon after your document has been approved for publication.  

Note that using GitHub for AUTH48 is still in the experimental phase, as we work with the community to identify the best process for all parties and update our tools to facilitate that process.  

Thanks,
Sandy 

> 
> Best,
> Chris
> 
>> On Sep 18, 2023, at 9:19 PM, [e-mail] wrote:
>> 
>> Authors,
>> 
>> While reviewing this document during AUTH48, please resolve (as necessary) the following questions, which are also in the XML file.
>> 
>> 1) <!-- [rfced] Please insert any keywords (beyond those that appear in the
>> title) for use on <https://www.rfc-editor.org/search>. -->
>> 
>> 
>> 2) <!-- [rfced] Please ensure that the guidelines listed in Section 2.1
>> of RFC 5743 have been adhered to in this document. -->
>> 
>> 
>> 3) <!-- [rfced] Section 1:
>> 
>> a) We updated this sentence to clarify that the family of variants is
>> specified by this document and not computed.  Please let us know any
>> objections.
>> 
>> Original:
>> This document specifies a protocol for computing RSA blind signatures
>> using RSA-PSS encoding, and a family of variants for this protocol,
>> denoted RSABSSA (RSA Blind Signature with Appendix).
>> 
>> Currently:
>> This document specifies (1) a protocol for computing RSA blind
>> signatures using RSA-PSS encoding and (2) a family of variants
>> (Section 5) for this protocol, denoted RSABSSA (RSA Blind Signature
>> with Appendix).
>> 
>> b) We see in other documents and in online searches that "RSABSSA" is
>> often listed as "RSA-BSSA" and defined as "RSA Blind Signature Scheme
>> with Appendix".  We also see that "RSA-BSSA" and (lowercased) "RSA
>> Blind Signature Scheme with Appendix" were used in version -01 of
>> this document but then changed, and we realize that any changes would
>> affect such listings as "RSABSSA-SHA384-PSS-Randomized" and
>> "RSABSSA-SHA384-PSS-Deterministic".
>> 
>> Please let us know if you would like to make any updates as related
>> to this term.  (We are fine either way but thought that this item was
>> worth pointing out.) -->
>> 
>> 
>> 4) <!-- [rfced] Section 4:  Should any of the artwork in this section
>> be sourcecode?  Please see
>> <https://www.rfc-editor.org/materials/sourcecode-types.txt>, and let
>> us know if any changes are needed.  If the sourcecode-types page
>> does not contain an applicable type, please let us know.
>> Also, if you use sourcecode, it is acceptable to leave the "type"
>> attribute unset. -->
>> 
>> 
>> 5) <!-- [rfced] Sections 4.1 through 4.4:  We changed the artwork to
>> sourcecode with type="pseudocode" in these sections.
>> 
>> See <https://www.rfc-editor.org/materials/sourcecode-types.txt> for a
>> list of sourcecode types.
>> 
>> Please review, and let us know any objections. -->
>> 
>> 
>> 6) <!-- [rfced] Section 4.2:  "If EMSA-PSS-ENCODE raises an error, raise
>> the error" reads oddly here.  Do two entities raise the same error,
>> or does one entity forward the error thrown by EMSA-PSS-ENCODE?
>> If you would like to rephrase, please provide alternative text.
>> 
>> Original:
>> 2. If EMSA-PSS-ENCODE raises an error, raise the error and stop
>> 
>> Perhaps:
>> 2. If EMSA-PSS-ENCODE raises an error, stop
>> 
>> Or possibly:
>> 2. If EMSA-PSS-ENCODE throws an error, raise the error and stop -->
>> 
>> 
>> 7) <!-- [rfced] Section 5:  We do not see "RSASSA-PSS" mentioned in
>> Section 9.1.1 of RFC 8017.  Is EMSA-PSS-ENCODE considered an
>> RSASSA-PSS parameter?  If yes, will this be clear to readers?
>> Please let us know if any changes are needed.
>> 
>> Original:
>> Each
>> variant specifies RSASSA-PSS parameters as defined in Section 9.1.1
>> of [RFC8017] and the type of message preparation function applied (as
>> described in Section 4.1). -->
>> 
>> 
>> 8) <!--[rfced]  Would it be correct to expand the first mention of “MGF1” as “mask generation function 1 (MGF1)" (per use in RFC 9151, which references RFC 8017), or do you prefer to leave the text as is (to match use in RFC 8017)?
>> 
>> Current:
>> Each variant uses the MGF1 mask generation function 
>> defined in Appendix B.2.1. of [RFC8017].
>> 
>> Perhaps:
>> Each variant uses the mask generation function 1 (MGF1) 
>> defined in Appendix B.2.1. of [RFC8017].
>> -->
>> 
>> 
>> 9) <!-- [rfced] Section 5:  We had trouble parsing these sentences.
>> If the suggested text is not correct, please provide clarifying text.
>> 
>> Original:
>> 1.  RSABSSA-SHA384-PSS-Randomized: This named variant uses SHA-384 as
>>    the hash function, MGF1 with SHA-384 as the PSS mask generation
>>    function, a 48-byte salt length, and uses the randomized
>>    preparation function (PrepareRandomize).
>> 
>> 2.  RSABSSA-SHA384-PSSZERO-Randomized: This named variant uses
>>    SHA-384 as the hash function, MGF1 with SHA-384 as the PSS mask
>>    generation function, an empty PSS salt, and uses the randomized
>>    preparation function (PrepareRandomize).
>> 
>> 3.  RSABSSA-SHA384-PSS-Deterministic: This named variant uses SHA-384
>>    as the hash function, MGF1 with SHA-384 as the PSS mask
>>    generation function, 48-byte salt length, and uses the identity
>>    preparation function (PrepareIdentity).
>> 
>> 4.  RSABSSA-SHA384-PSSZERO-Deterministic: This named variant uses
>>    SHA-384 as the hash function, MGF1 with SHA-384 as the PSS mask
>>    generation function, an empty PSS salt, and uses the identity
>>    preparation function (PrepareIdentity).  This is the only variant
>>    that produces deterministic signatures over the client's input
>>    message msg.
>> 
>> Suggested:
>> RSABSSA-SHA384-PSS-Randomized:  This named variant uses SHA-384 as
>>   the hash function, MGF1 with SHA-384 as the PSS mask generation
>>   function, and a 48-byte salt length; it also uses the randomized
>>   preparation function (PrepareRandomize).
>> 
>> RSABSSA-SHA384-PSSZERO-Randomized:  This named variant uses SHA-384
>>   as the hash function, MGF1 with SHA-384 as the PSS mask generation
>>   function, and an empty PSS salt; it also uses the randomized
>>   preparation function (PrepareRandomize).
>> 
>> RSABSSA-SHA384-PSS-Deterministic:  This named variant uses SHA-384 as
>>   the hash function, MGF1 with SHA-384 as the PSS mask generation
>>   function, and a 48-byte salt length; it also uses the identity
>>   preparation function (PrepareIdentity).
>> 
>> RSABSSA-SHA384-PSSZERO-Deterministic:  This named variant uses
>>   SHA-384 as the hash function, MGF1 with SHA-384 as the PSS mask
>>   generation function, and an empty PSS salt; it also uses the
>>   identity preparation function (PrepareIdentity).  This is the
>>   only variant that produces deterministic signatures over the
>>   client's input message msg. -->
>> 
>> 
>> 10) <!-- [rfced] Section 6.1:  "errors generated throughout this
>> specification" reads oddly.  If the suggested text is not
>> acceptable, please provide alternative text.
>> 
>> Original:
>> The explicit errors generated throughout this specification, along
>> with the conditions that lead to each error, are listed in the
>> definitions for Blind, BlindSign, and Finalize.
>> 
>> Suggested:
>> The generation of explicit errors as discussed throughout this
>> specification, along with the conditions that lead to each error,
>> are listed in the definitions for Blind, BlindSign, and Finalize. -->
>> 
>> 
>> 11) <!-- [rfced] Section 6.2:  Should "RSASSA-PSS OID" be "id-RSASSA-PSS
>> OID" per RFC 5756?
>> 
>> Original:
>> If the server public key is carried in an X.509 certificate, it MUST
>> use the RSASSA-PSS OID [RFC5756]. -->
>> 
>> 
>> 12) <!-- [rfced] Section 7:
>> 
>> a) We don't see any mention of "PrepareRandomize" or "preparation"
>> (as in "randomized preparation function (PrepareRandomize)" from
>> Section 5) in [Lys22].  Will this text and citation be clear to
>> readers?
>> 
>> Original:
>> Lysyanskaya also proved that the RSABSSA variants which use the
>> PrepareRandomize function achieve blindness in [Lys22].
>> 
>> b) We don't see any mention of "PrepareIdentity" in Section 7.3.
>> Will this text and citation be clear to readers?
>> 
>> Original:
>> However, additional
>> assumptions on the message inputs are required for blindness to hold
>> for RSABSSA variants that use the PrepareIdentity function; see
>> Section 7.3 for more discussion on those results. -->
>> 
>> 
>> 13) <!-- [rfced] Section 7.4:  Because this is the first mention of
>> "message randomizer prefix", we updated this sentence for ease of the
>> reader.  Please let us know any objections.
>> 
>> Original:
>> All random values in the protocol, including the salt, message
>> randomizer prefix, and random blind value in Blind, MUST be generated
>> from a cryptographically secure random number generator [RFC4086].
>> 
>> Currently:
>> All random values in the protocol, including the salt, message
>> randomizer prefix (msg_prefix; see Appendix A), and random blind
>> value in Blind, MUST be generated from a cryptographically secure
>> random number generator [RFC4086]. -->
>> 
>> 
>> 14) <!-- [rfced] Section 7.6:
>> 
>> a) We do not see any mention of "v3" or "version 3" as related to
>> X.509 in RFC 4055.  Will this citation be clear to readers?
>> 
>> Original:
>> First, it is recommended in recent
>> standards, including TLS 1.3 [RFC8446], X.509v3 [RFC4055], and even
>> PKCS#1 itself.
>> 
>> b) Because this text is quoted, we updated it to match the text in
>> RFC 8017.  Please let us know any concerns; for example, if you wish
>> to keep "recommended for eventual adoption", the quotes will need to
>> be removed.
>> 
>> Original:
>> According to [RFC8017], "Although no attacks are
>> known against RSASSA-PKCS#1 v1.5, in the interest of increased
>> robustness, RSA-PSS [RFC8017] is recommended for eventual adoption in
>> new applications."
>> 
>> Currently:
>> According to [RFC8017], "Although no attacks are known
>> against RSASSA-PKCS1-v1_5, in the interest of increased robustness,
>> RSASSA-PSS is REQUIRED in new applications."
>> 
>> c) We could not find "RSASSA-PKCS#1 v1.5" in any published RFC.
>> We changed "RSASSA-PKCS#1 v1.5" to "RSASSA-PKCS1-v1_5" per
>> RFC 8017 and other published RFCs accordingly.  Please let us know
>> any concerns.
>> 
>> Original:
>> While RSA-PSS is more complex than RSASSA-PKCS#1
>> v1.5 encoding, ubiquity of RSA-PSS support influenced the design
>> decision in this draft, despite PKCS#1 v1.5 having equivalent
>> security properties for digital signatures [JKM18].
>> 
>> Currently:
>> While RSA-PSS is more
>> complex than RSASSA-PKCS1-v1_5 encoding, ubiquity of RSA-PSS support
>> influenced the design decision in this document, despite PKCS #1 v1.5
>> having equivalent security properties for digital signatures [JKM18].
>> 
>> d) We do not see any mention of "FDH" or the word "full" in [RSA-FDH].
>> Will this citation be clear to readers?
>> 
>> Original:
>> Full Domain Hash (FDH) [RSA-FDH] encoding is also possible, and this
>> variant has equivalent security to PSS [KK18]. -->
>> 
>> 
>> 15) <!-- [rfced] Informative References:  As we have found that some
>> ".edu" pages are not always stable*, may we update the listings
>> below as follows?
>> 
>> * (although we could not find an alternative to the page provided for
>> [Chaum83])
>> 
>> Original:
>> [RSA-FDH]  Bellare, M. and P. Rogaway, "Random Oracles are Practical:
>>           A Paradigm for Designing Efficient Protocols", October
>>           1995, <https://cseweb.ucsd.edu/~mihir/papers/ro.pdf>.
>> 
>> Suggsted:
>> [RSA-FDH]  Bellare, M. and P. Rogaway, "Random Oracles are Practical:
>>           A Paradigm for Designing Efficient Protocols", CCS '93:
>>           Proceedings of the 1st ACM conference on Computer and
>>           communications security, pp. 62-73, DOI 10.1145/
>>           168588.168596, December 1993, <https://dl.acm.org/doi/
>>           abs/10.1145/168588.168596>.
>> ...
>> Original:
>> [RemoteTimingAttacks]
>>           Boneh, D. and D. Brumley, "Remote Timing Attacks are
>>           Practical", 12th Usenix Security Symposium, May 2003,
>>           <https://crypto.stanford.edu/~dabo/papers/ssl-timing.pdf>.
>> 
>> Suggested:
>> [RemoteTimingAttacks]
>>           Brumley, D. and D. Boneh, "Remote Timing Attacks are
>>           Practical", Proceedings of the 12th USENIX Security
>>           Symposium, August 2003,
>>           <https://www.usenix.org/legacy/events/sec03/tech/brumley/
>>           brumley.pdf>. -->
>> 
>> 
>> 16) <!-- [rfced] Informative References:  Per
>> <https://doi.org/10.6028/nist.fips.186-4>, which steers to
>> <https://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.186-4.pdf>, FIPS
>> 186-4 has been superseded by FIPS 186-5.  May we update as suggested?
>> 
>> Original:
>> The RECOMMENDED method for generating the server signing key pair is
>> as specified in FIPS 186-4 [DSS].
>> ...
>> [DSS]      "Digital Signature Standard (DSS)", National Institute of
>>           Standards and Technology report,
>>           DOI 10.6028/nist.fips.186-4, July 2013,
>>           <https://doi.org/10.6028/nist.fips.186-4>.
>> 
>> Suggested:
>> The RECOMMENDED method for generating the server signing key pair is
>> as specified in FIPS 186-5 [DSS].
>> ...
>> [DSS]      "Digital Signature Standard (DSS)", National Institute of
>>           Standards and Technology report,
>>           DOI 10.6028/nist.fips.186-5, February 2023,
>>           <https://doi.org/10.6028/NIST.FIPS.186-5>. -->
>> 
>> 
>> 17) <!-- [rfced] Informative References:  The following references are
>> not cited anywhere in this document.  Please let us know where they
>> should be cited; otherwise, the listings will be removed.
>> 
>> Side note regarding [UProve]:  If this listing is to be kept, please
>> advise regarding the currently listed date.  We could not find a
>> February 2012 version.  Is this date correct?
>> 
>> Original:
>> [BLS-Proposal]
>>           Ladd, W., "[Privacy-pass] External verifiability: a
>>           concrete proposal", July 2020,
>>           <https://mailarchive.ietf.org/arch/msg/privacy-pass/
>>           BDOOhSLwB3uUJcfBiss6nUF5sUA/>.
>> ...
>> [KLRX20]   Kastner, J., Loss, J., Rosenberg, M., and J. Xu, "On
>>           Pairing-Free Blind Signature Schemes in the Algebraic
>>           Group Model", September 2020,
>>           <https://eprint.iacr.org/2020/1071>.
>> ...
>> [PolytimeROS]
>>           Benhamouda, F., Lepoint, T., Loss, J., Orru, M., and M.
>>           Raykova, "On the (in)security of ROS", July 2020,
>>           <https://eprint.iacr.org/2020/945>.
>> ...
>> [TZ22]     Tessaro, S. and C. Zhu, "Short Pairing-Free Blind
>>           Signatures with Exponential Security", January 2022,
>>           <https://eprint.iacr.org/2022/047>.
>> ...
>> [UProve]   Microsoft, "U-Prove", February 2012,
>>           <https://www.microsoft.com/en-us/research/project/
>>           u-prove/>. -->
>> 
>> 
>> 18) <!-- [rfced] Appendices A.1 through A.4:  We changed the artwork to
>> sourcecode with type="test-vectors".
>> 
>> See <https://www.rfc-editor.org/materials/sourcecode-types.txt> for a
>> list of sourcecode types.
>> 
>> Please review, and let us know any objections. -->
>> 
>> 
>> 19) <!-- [rfced] Please review the "Inclusive Language" portion of the
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>> <https://www.rfc-editor.org/styleguide/part2/#inclusive_language>,
>> and let us know if any changes are needed.
>> 
>> Note that our script did not flag any words in particular, but this
>> should still be reviewed as a best practice. -->
>> 
>> 
>> 20) <!-- [rfced] Please let us know if any changes are needed for the
>> following:
>> 
>> a) The following terms were used inconsistently in this document.
>> We chose to use the latter forms.  Please let us know any objections.
>> 
>> Random Oracle Model / random oracle model (per RFC 8017)
>> 
>> zero knowledge proofs / zero-knowledge proofs
>> 
>> b) The following term appears to be used inconsistently in this
>> document.  Please let us know which form is preferred.
>> 
>> signature-message pair (1 instance) /
>>  (message, signature) pair (3 instances in Section 7.5)
>> 
>> c) Should "random prefix" in Section 4.5 be "message randomizer
>> prefix" or perhaps "msg_prefix"? -->
>> 
>> 
>> Thank you.
>> 
>> RFC Editor/lb/ap
>> 
>> 
>> On Sep 18, 2023, at 6:18 PM, [e-mail] wrote:
>> 
>> *****IMPORTANT*****
>> 
>> Updated 2023/09/18
>> 
>> RFC Author(s):
>> --------------
>> 
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>> Files 
>> -----
>> 
>> The files are available here:
>>  https://www.rfc-editor.org/authors/rfc9474.xml
>>  https://www.rfc-editor.org/authors/rfc9474.html
>>  https://www.rfc-editor.org/authors/rfc9474.pdf
>>  https://www.rfc-editor.org/authors/rfc9474.txt
>> 
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>> Please let us know if you have any questions.  
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>> Thank you for your cooperation,
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>> RFC Editor
>> 
>> --------------------------------------
>> RFC9474 (draft-irtf-cfrg-rsa-blind-signatures-14)
>> 
>> Title            : RSA Blind Signatures
>> Author(s)        : F. Denis, F. Jacobs, C. A. Wood
>> WG Chair(s)      : 
>> Area Director(s) : 
>> 
>> 
>