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privacysandbox / protected-auction-key-value-service

Protected Auction Key/Value Service
Apache License 2.0
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Privacy budget for monitoring/telemetry #61

Open fhoering opened 2 weeks ago

fhoering commented 2 weeks ago

The monitoring metrics part is described here

These metrics are noised using Differential Privacy.

It mentions that the metrics are noised with DP but not how the privacy budget is allocated. It seems like the noising scheme is applying global DP with an epsilon of 5 (see here)

Can you give more information on how the budget is allocated across metrics, how it is reset and how the noise is added (gaussian vs laplace) ?

Did you make some tests on how the current implementation affects the metrics usability (number of contributions & number of metrics vs budget & max received queries) ?

How has the decision between noising and not noising metrics been taken ? What about Memory and CPU metrics for example ?

What about custom metrics initiated from the UDFs ?

emmafu2022 commented 2 weeks ago

Hi @fhoering, we are working on the monitoring documentation which will provide information relevant to your questions. Will provide the link here once it is published. Thanks!

fhoering commented 2 weeks ago

In addition to more documentation I think some real benchmark or writeup on usability would be interesting. As the budget depends on sensitivity and is split across all metrics it is difficult to see if the noise level becomes significant or not. It really depends on the number of metrics, the received queries and the budget reset period.