Oblivious Message Retrieval

Hello Zcash community!
We recently posted a ZOMG application to develop Oblivious Message Retrieval (OMR), a technique to support private transaction retrieval for light clients.

Here is the link to the proposal: ZF Grants - Oblivious Message Retrieval
Here is the full version of the proposal: Research Proposal for Oblivious Message Retrieval - HackMD
Please see section 11 in our paper for a detailed discussion regarding Zcash integration considerations.

We would love to hear your feedback or comments and would be happy to answer any questions of yours!
Thank you all!

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Welcome to the Zcash community Thomas!

I am glad to see a research driven grant that is in line with my post:

Thank you for submitting this proposal to research and deliver an alternative way to improve the operations & privacy of light client communication.

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Welcome to the Zcash community Thomas!

This is an awesome proposal that can improve privacy and the UX of Zcash wallets.

Is OMR similar to Fuzzy Message Detection (FMD)? In other words, does the compact encrypted digest sent by lightwalletd servers contain only the associated notes of each recipients or will there be false positives too like in FMD?

Anyway, good luck with the project!

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Thank you for your support for your post @aiyadt!

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Thank you for your support @tokidoki!

OMR is different from FMD. OMR always provides full privacy, and the privacy is independent of the false positive rate.
In general, the digest would contain false positives, but with only a very small probability (e.g., in the paper/demo, we set false positive rate to be 2^{-21}, and can be set to smaller like 2^{-40} without affecting privacy).
There are several other differences and we provide a more comprehensive comparison with FMD in table 1+ section 2.1 in our paper.

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Got it. So, OMR is not decoy-based privacy which is great!

Can’t wait to see this in action. :grin:

Not sure when ZOMG will decide on the proposal but it’s a hard yes from me.

P.S: I’m not on ZOMG board.

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Thank you for your support! The importance of your support is definitely independent of the ZOMG-board-ness :wink:.

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I approve this grant as a community member.

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Thank you for your support @dontbeevil!

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Congratulations ZCash Community. Something is going right if these are the grant applications we are receiving.

Good luck @thomaslzy!

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Thank you for your support @GGuy! Glad that you like our project and proposal. Happy holidays :smiley:

Hi @thomaslzy, I’m glad to inform you that the ZOMG is supportive of your grant application! Your work will contribute towards the goal of buttressing end-to-end privacy coverage across Zcash’s different clients/user journeys. @tromer of course is a welcome source of confidence and oversight.

Two things:

  1. Could you integrate OMR with Zecwallet Lite @adityapk00 and Zwallet @hanh, in addition to Nighthawk? These are important wallets to the Zcash community (Zecwallet having the longest history and a large userbase)
  2. It seems that your PhD admission details are not yet finalized. We’d like to express that the grant is covered/capped up to $98k. If the amount increases for any reason, you will have to resubmit to the next ZOMG panel (which starts some time in January)
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Hello @ml_sudo,
That’s great news! Thank you for your and ZOMG’s support.

To answer your questions:

  1. We are surely happy to also work with Zecwallet Lite @adityapk00 and Zwallet @hanh team to integrate the OMR library with these two wallets. Please also note that as indicated in the application, the full integration of the OMR library with any wallet is not part of this project, but rather we will support integrations done by the wallets’ primary developers (including trying to adapt our library to their needs).
  2. I surely understand that. Thank you for the reminder.

Thanks again for your and the community’s support!

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Congratulation on the grant Thomas! In the Zcash community, you get what you put in!
Myself and @NighthawkWallet developers are excited to work with you to deliver the end-to-end support for private transaction retrieval for light clients. :raised_hands:

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Thank you @aiyadt! Exited to work with you and @NighthawkWallet team on private transaction retrieval as well :-).

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Hello all!

Regarding our project, here are some quick updates:

  1. We have found additional optimizations that make our server runtime 1.5-2x faster (based on hardware) and will update the new GCP runtime in our open-source directory.
  2. We have updated the write-up of our original paper and submitted it to a recent conference.
  3. We are also working on the group OMR project.
  4. We have had regular meetings with the Nighthawk team for APIs.
  5. Code development is ongoing.

Thank you!

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Hello all!

Regarding our project, here are some quick updates:

  1. Milestone 2 is finished. Code is publicly available at GitHub - ZeyuThomasLiu/ObliviousMessageRetrieval at lib
  2. We are making progress on Milestone 3 and 4 at the same time. We will send updates accordingly.
  3. We have also recently made OMR ~2.5x faster on the detector side (part of milestone 9). The code will be made publicly available soon.

Thank you!

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Hello, @ZcashGrants!

Regarding our project, we would like to propose a grant budget plan change for approval.
The total budget and the milestone accomplishing time will remain the same.

The reasons that we would like to propose such change are:
(1) We would like to include a new team member Yunhao Wang, currently an MS student at Columbia University, and previously a software engineer at Amazon for ~3.5 years.
She will mainly contribute to the group OMR part of the project, including but not limited to implementation, testing, and algorithm design. She will be compensated by part of the original grant. The specific number is determined by her time spent on the project.
We believe her software engineering skills and enthusiasm for cryptography research would greatly help the research project and make the library better implemented.
(2) The original proposal was to support one academic year of Zeyu’s Ph.D. study but did not specify the specific time frame. We would also like to specify which year the grant is supposed to support, per university policy.

We posted a more detailed budget plan in the discussion section of our proposal.

Please let us know if you have any questions or suggestions.

Thank you very much!

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Hello @thomaslzy. Sorry for the delay getting back to you. We are okay with the above changes you made related to the budget for your grant proposal. Thanks!

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Hello @aquietinvestor, that’s great! Thank you very much for your reply!

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