jiebi/CodeConvo huggingface dataset:
Code change:
AggregateShareReq should have an aggregation parameter field instead of aggregation job ID.
Thanks NAME for spotting this!

Related discussion:
text: "batch_interval" is the batch interval of the request. <ins> "agg_param", an aggregation parameter for the VDAF being executed. </ins> "report_count" is the number of reports included in the aggregation. "checksum" is the checksum computed over the set of client reports. <del> "job_id" is the ID of the aggregation job. </del> This request MUST be authenticated as described in https-sender-auth. To handle the leader's request, the helper first ensures that the request meets the requirements for batch parameters following the
Code change:
Align with the latest VDAF draft. This requires two minor protocol changes: 02 added a value called the "publicshare" to the VDAF syntax. This is to support Poplar1 (and likely other schemes that need a similar extractability property). To accommodate this, the publicshare field has been added to the Report and ReportShare structures and appended to the AAD for input share encryption. (This may end up being useful for privacy.) 02 added the report count to the aggregate result computation. This is already passed to the Collector in the CollectResp, so we just need to update the aggregate result computation in the draft to match.
Rebased and pushed a minor update: The public share in Report and ReportStore now both have the same length prefix.
Rebased.
This will be VDAF-02 or 03, depending on when we need to cut DAP-02.
VDAF-03 is out, I will send a PR by end of week. URL

Related discussion:
text: where "[leader]" is the first entry in the task's aggregator endpoints.  The payload is structured as follows: <del> This message is called the Client's report.  It consists of a "header" and the encrypted input share of each of the Aggregators. The header consists of the task ID and report "metadata".  The metadata consists of the following fields: </del> <ins> This message is called the Client's report.  It consists of the report metaata, the "public share" output by the VDAF's input- distribution algorithm, and the encrypted input share of each of the Aggregators.  The header consists of the task ID and report "metadata".  The metadata consists of the following fields: </ins> A timestamp representing the time at which the report was generated.  Specifically, the "time" field is set to the number of
Code change:
Align with the latest VDAF draft. This requires two minor protocol changes: 02 added a value called the "publicshare" to the VDAF syntax. This is to support Poplar1 (and likely other schemes that need a similar extractability property). To accommodate this, the publicshare field has been added to the Report and ReportShare structures and appended to the AAD for input share encryption. (This may end up being useful for privacy.) 02 added the report count to the aggregate result computation. This is already passed to the Collector in the CollectResp, so we just need to update the aggregate result computation in the draft to match.
Rebased and pushed a minor update: The public share in Report and ReportStore now both have the same length prefix.
Rebased.
This will be VDAF-02 or 03, depending on when we need to cut DAP-02.
VDAF-03 is out, I will send a PR by end of week. URL

Related discussion:
text: 4.4.1.3. Each report share has a corresponding task ID, report metadata <del> (timestamp, nonce, and extensions), and encrypted input share.  Let "task_id", "metadata", and "encrypted_input_share" denote these values, respectively.  Given these values, an aggregator decrypts the input share as follows.  First, the aggregator looks up the HPKE config and corresponding secret key indicated by </del> <ins> (timestamp, nonce, and extensions), the public share sent to each Aggregator, and the recipient's encrypted input share.  Let "task_id", "metadata", "public_share", and "encrypted_input_share" denote these values, respectively.  Given these values, an aggregator decrypts the input share as follows.  First, the aggregator looks up the HPKE config and corresponding secret key indicated by </ins> "encrypted_input_share.config_id".  If not found, then it marks the report share as invalid with the error "hpke-unknown-config-id". Otherwise, it decrypts the payload with the following procedure:
Code change:
Align with the latest VDAF draft. This requires two minor protocol changes: 02 added a value called the "publicshare" to the VDAF syntax. This is to support Poplar1 (and likely other schemes that need a similar extractability property). To accommodate this, the publicshare field has been added to the Report and ReportShare structures and appended to the AAD for input share encryption. (This may end up being useful for privacy.) 02 added the report count to the aggregate result computation. This is already passed to the Collector in the CollectResp, so we just need to update the aggregate result computation in the draft to match.
Rebased and pushed a minor update: The public share in Report and ReportStore now both have the same length prefix.
Rebased.
This will be VDAF-02 or 03, depending on when we need to cut DAP-02.
VDAF-03 is out, I will send a PR by end of week. URL

Related discussion:
text: "vdaf_verify_key" is the VDAF verification key shared by the aggregators; "agg_id" is the aggregator ID ("0x00" for the Leader and <del> "0x01" for the helper); and "agg_param" is the opaque aggregation parameter distributed to the aggregtors by the collector. </del> <ins> "0x01" for the helper); "agg_param" is the opaque aggregation parameter distributed to the aggregtors by the collector; "public_share" is the public share generated by the client and distributed to each aggregator; and "input_share" is the aggregator's input share. </ins> If either step fails, the aggregator marks the report as invalid with error "vdaf-prep-error".  Otherwise, the value "out" is interpreted
Code change:
Align with the latest VDAF draft. This requires two minor protocol changes: 02 added a value called the "publicshare" to the VDAF syntax. This is to support Poplar1 (and likely other schemes that need a similar extractability property). To accommodate this, the publicshare field has been added to the Report and ReportShare structures and appended to the AAD for input share encryption. (This may end up being useful for privacy.) 02 added the report count to the aggregate result computation. This is already passed to the Collector in the CollectResp, so we just need to update the aggregate result computation in the draft to match.
Rebased and pushed a minor update: The public share in Report and ReportStore now both have the same length prefix.
Rebased.
This will be VDAF-02 or 03, depending on when we need to cut DAP-02.
VDAF-03 is out, I will send a PR by end of week. URL

Related discussion:
text: aggregate shares into an aggregate result using the VDAF's "agg_shares_to_result" algorithm.  In particular, let "agg_shares" denote the ordered sequence of aggregator shares, ordered by <del> aggregator index, and let "agg_param" be the opaque aggregation parameter.  The final aggregate result is computed as follows: </del> <ins> aggregator index, let "report_count" denote the report count sent by the Leader, and let "agg_param" be the opaque aggregation parameter. The final aggregate result is computed as follows: </ins> 4.5.4.
Code change:
And while we're at it, update an obsolete reference to Oblivious HTTP, which has long since been adopted by its WG. VDAF-05 isn't expected until Monday 3/13, but we can get this change ready to go.
DAP-04 will need some routine changes: [x] Update version tags for HPKE to () [x] Bump VDAF-03 to 05 () [x] Update change log () [x] Run spell check ()

Related discussion:
text: participating clients or permit some attacks on robustness.  This auxiliary information could be removed by having clients submit reports to an anonymizing proxy server which would then use Oblivious <del> HTTP I-D.thomson-http-oblivious to forward inputs to the DAP leader, without requiring any server participating in DAP to be aware of whatever client authentication or attestation scheme is in use. </del> <ins> HTTP I-D.draft-ietf-ohai-ohttp-07 to forward inputs to the DAP leader, without requiring any server participating in DAP to be aware of whatever client authentication or attestation scheme is in use. </ins> 7.4.
Code change:
Partially addresses . (We also need to decide if/how to allow a particular PA protocol to use multiple helpers for privacy.) Right now, multiple helpers are used for redundancy in case one of the helpers dropped out. This removes this mechanism from the core protocol.
Squashed and rebased.
That's a good idea,
Hmm... Do we need to decide. Per our discussion on Wednesday, if the clients learn this out of band then we won't need this field at all because clients will get it separately and helpers don't need to know what the other helpers are, right?
My takeaway is that the parameters must contain all input needed to run the protocol, including the helpers. And all of this is configured out of band. You could punt everything except for the cryptographic goop out of the parameters structure, forcing clients to know the leader and helper and get their public keys out of band as well, which would be fine. It's just different. I think both work just fine, but I lean towards having params specify everything. It just seems simpler to me. That said... making public key discovery part of the client upload protocol here is more complex, I think. So, .
Squashed.
LGTM. Multiple helpers "for privacy" seems like it's inherently a per-protocol thing (Prio supports it, Hits does not). If and when we decide to address that, should we move this to the protocol-specific slot in PAParam?

Related discussion:
text: *Collect:* The collector makes one or more requests to the leader in order to obtain the final output of the protocol.  Before the output can be computed, the aggregators (i.e, the leader and <del> helpers) need to have verified and aggregated a sufficient number </del> <ins> helper) need to have verified and aggregated a sufficient number </ins> of inputs.  Depending on the PA protocol, it may be possible for the aggregators to do so immediately when reports are uploaded. (See prio.)  However, in general it is necessary for them to wait until (a) enough reports have been uploaded and (b) the collector has made a request.  (See hits.) <del> [TODO: Say that the protocol involves multiple helpers.  The downside of using secret sharing is that the protocol requires at least two servers to be online during the entire data aggregation process.  To ameliorate this problem, we run the protocol in parallel with multiple helpers.] </del> 3. This section specifies a protocol for executing generic PA tasks.
Code change:
Partially addresses . (We also need to decide if/how to allow a particular PA protocol to use multiple helpers for privacy.) Right now, multiple helpers are used for redundancy in case one of the helpers dropped out. This removes this mechanism from the core protocol.
Squashed and rebased.
That's a good idea,
Hmm... Do we need to decide. Per our discussion on Wednesday, if the clients learn this out of band then we won't need this field at all because clients will get it separately and helpers don't need to know what the other helpers are, right?
My takeaway is that the parameters must contain all input needed to run the protocol, including the helpers. And all of this is configured out of band. You could punt everything except for the cryptographic goop out of the parameters structure, forcing clients to know the leader and helper and get their public keys out of band as well, which would be fine. It's just different. I think both work just fine, but I lean towards having params specify everything. It just seems simpler to me. That said... making public key discovery part of the client upload protocol here is more complex, I think. So, .
Squashed.
LGTM. Multiple helpers "for privacy" seems like it's inherently a per-protocol thing (Prio supports it, Hits does not). If and when we decide to address that, should we move this to the protocol-specific slot in PAParam?

Related discussion:
text: "task": The PA task. <del> "helper_urls": The helpers' endpoint URLs. </del> <ins> "helper_url": The helpers endpoint URL. </ins> "collector_config": The HPKE configuration of the collector (described in hpke-config).  [OPEN ISSUE: Maybe the collector's
Code change:
Partially addresses . (We also need to decide if/how to allow a particular PA protocol to use multiple helpers for privacy.) Right now, multiple helpers are used for redundancy in case one of the helpers dropped out. This removes this mechanism from the core protocol.
Squashed and rebased.
That's a good idea,
Hmm... Do we need to decide. Per our discussion on Wednesday, if the clients learn this out of band then we won't need this field at all because clients will get it separately and helpers don't need to know what the other helpers are, right?
My takeaway is that the parameters must contain all input needed to run the protocol, including the helpers. And all of this is configured out of band. You could punt everything except for the cryptographic goop out of the parameters structure, forcing clients to know the leader and helper and get their public keys out of band as well, which would be fine. It's just different. I think both work just fine, but I lean towards having params specify everything. It just seems simpler to me. That said... making public key discovery part of the client upload protocol here is more complex, I think. So, .
Squashed.
LGTM. Multiple helpers "for privacy" seems like it's inherently a per-protocol thing (Prio supports it, Hits does not). If and when we decide to address that, should we move this to the protocol-specific slot in PAParam?

Related discussion:
text: 3.3.2. <del> For each URL "[helper]" in "PAUploadStartResp.helper_urls", the client sends a GET request to "[helper]/key_config".  The helper responds with status 200 and an "HpkeConfig" message.  Next, the client collects the set of helpers it will upload shares to.  It ignores a helper if: </del> <ins> Let "[helper]" denote the helper URL encoded by "PAUploadStartResp.param.helper_url".  When a client sends a GET request to "[helper]/key_config", the helper responds with status 200 and an "HpkeConfig" message.  The client aborts if any of the following happen: </ins> the client and helper failed to establish a secure, helper- authenticated channel;
Code change:
Partially addresses . (We also need to decide if/how to allow a particular PA protocol to use multiple helpers for privacy.) Right now, multiple helpers are used for redundancy in case one of the helpers dropped out. This removes this mechanism from the core protocol.
Squashed and rebased.
That's a good idea,
Hmm... Do we need to decide. Per our discussion on Wednesday, if the clients learn this out of band then we won't need this field at all because clients will get it separately and helpers don't need to know what the other helpers are, right?
My takeaway is that the parameters must contain all input needed to run the protocol, including the helpers. And all of this is configured out of band. You could punt everything except for the cryptographic goop out of the parameters structure, forcing clients to know the leader and helper and get their public keys out of band as well, which would be fine. It's just different. I think both work just fine, but I lean towards having params specify everything. It just seems simpler to me. That said... making public key discovery part of the client upload protocol here is more complex, I think. So, .
Squashed.
LGTM. Multiple helpers "for privacy" seems like it's inherently a per-protocol thing (Prio supports it, Hits does not). If and when we decide to address that, should we move this to the protocol-specific slot in PAParam?

Related discussion:
text: the key config specifies a KEM, KDF, or AEAD algorithm the client doesn't recognize. <del> If the set of supported helpers is empty, then the client aborts and alerts the leader with "no supported helpers".  Otherwise, for each supported helper the client issues a POST request to "[leader]/upload_finish" with a payload constructed as described below. </del> [OPEN ISSUE: Should the request URL encode the PA task?  This would be necessary if we make "upload_start" an idempotent GET per issue#48.]
Code change:
Partially addresses . (We also need to decide if/how to allow a particular PA protocol to use multiple helpers for privacy.) Right now, multiple helpers are used for redundancy in case one of the helpers dropped out. This removes this mechanism from the core protocol.
Squashed and rebased.
That's a good idea,
Hmm... Do we need to decide. Per our discussion on Wednesday, if the clients learn this out of band then we won't need this field at all because clients will get it separately and helpers don't need to know what the other helpers are, right?
My takeaway is that the parameters must contain all input needed to run the protocol, including the helpers. And all of this is configured out of band. You could punt everything except for the cryptographic goop out of the parameters structure, forcing clients to know the leader and helper and get their public keys out of band as well, which would be fine. It's just different. I think both work just fine, but I lean towards having params specify everything. It just seems simpler to me. That said... making public key discovery part of the client upload protocol here is more complex, I think. So, .
Squashed.
LGTM. Multiple helpers "for privacy" seems like it's inherently a per-protocol thing (Prio supports it, Hits does not). If and when we decide to address that, should we move this to the protocol-specific slot in PAParam?

Related discussion:
text: that about a client?  I'm not sure, so I'd be inclined to remove this unless we have a concrete use case.] <del> The client begins by setting up an HPKE I-D.irtf-cfrg-hpke context for the helper by running </del> <ins> Next, the client issues a POST request to "[leader]/upload_finish". It begins by setting up an HPKE I-D.irtf-cfrg-hpke context for the helper by running </ins> where "pk" is the KEM public key encoded by "HpkeConfig.public_key". The outputs are the helper's encapsulated context "enc" and the
Code change:
Partially addresses . (We also need to decide if/how to allow a particular PA protocol to use multiple helpers for privacy.) Right now, multiple helpers are used for redundancy in case one of the helpers dropped out. This removes this mechanism from the core protocol.
Squashed and rebased.
That's a good idea,
Hmm... Do we need to decide. Per our discussion on Wednesday, if the clients learn this out of band then we won't need this field at all because clients will get it separately and helpers don't need to know what the other helpers are, right?
My takeaway is that the parameters must contain all input needed to run the protocol, including the helpers. And all of this is configured out of band. You could punt everything except for the cryptographic goop out of the parameters structure, forcing clients to know the leader and helper and get their public keys out of band as well, which would be fine. It's just different. I think both work just fine, but I lean towards having params specify everything. It just seems simpler to me. That said... making public key discovery part of the client upload protocol here is more complex, I think. So, .
Squashed.
LGTM. Multiple helpers "for privacy" seems like it's inherently a per-protocol thing (Prio supports it, Hits does not). If and when we decide to address that, should we move this to the protocol-specific slot in PAParam?

Related discussion:
text: SetupBaseS() will be, as well as the aad for context.Seal().  The aad might be the entire "transcript" between the client and helper.] <del> [OPEN ISSUE: Is it safe to generate the proof once, then secret-share between each (leader, helper) pair?  Probably not in general, but maybe for Prio?] </del> [OPEN ISSUE: allow server to send joint randomness in UploadStartResp, and then enforce uniqueness via double-spend state or something else (see issue#48).]
Code change:
Partially addresses . (We also need to decide if/how to allow a particular PA protocol to use multiple helpers for privacy.) Right now, multiple helpers are used for redundancy in case one of the helpers dropped out. This removes this mechanism from the core protocol.
Squashed and rebased.
That's a good idea,
Hmm... Do we need to decide. Per our discussion on Wednesday, if the clients learn this out of band then we won't need this field at all because clients will get it separately and helpers don't need to know what the other helpers are, right?
My takeaway is that the parameters must contain all input needed to run the protocol, including the helpers. And all of this is configured out of band. You could punt everything except for the cryptographic goop out of the parameters structure, forcing clients to know the leader and helper and get their public keys out of band as well, which would be fine. It's just different. I think both work just fine, but I lean towards having params specify everything. It just seems simpler to me. That said... making public key discovery part of the client upload protocol here is more complex, I think. So, .
Squashed.
LGTM. Multiple helpers "for privacy" seems like it's inherently a per-protocol thing (Prio supports it, Hits does not). If and when we decide to address that, should we move this to the protocol-specific slot in PAParam?

Related discussion:
text: We sometimes refer to this message as the _report_. The message contains the "task" fields of the previous request.  In addition, it includes the time (in seconds since the beginning of UNIX time) at <del> which the report was generated, the helper's HPKE config id, endpoint URL, and the helper and leader shares.  The helper share has the following structure: </del> <ins> which the report was generated, the helper's HPKE config id, and the helper and leader shares.  The helper share has the following structure: </ins> Field "enc" encodes the helper's encapsulated HPKE context.  The remainder of the structure contains the share itself, the structure