74 lines
3.4 KiB
Markdown
74 lines
3.4 KiB
Markdown
---
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title: "Introducing mCaptcha net"
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description: "A network of mCaptcha instances sharing PoW stats to make mCaptcha more efficient and accessible"
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date: 2023-10-19
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lastmod: 2023-10-19
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draft: false
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weight: 50
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images: ["icon.png"]
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contributors: ["Aravinth Manivannan"]
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---
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mCaptcha uses a Proof-of-Work (PoW) based algorithm to offer
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Denial-of-Service protection, because of [its excellent accessibility
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characteristics](https://www.w3.org/TR/turingtest/#proof-of-work). PoW
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within mCaptcha is configuration --- webmasters can configure
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[difficulty factors](/docs/terminology/difficulty-factor) for their
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installations, which determines waiting time for visitors. But PoW can
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become inaccessible if webmasters choose a very high difficulty factor.
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So they have to maintain a balance which imposes sufficient load on DDoS
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attackers while also being accessible to common folk.
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{{< alert icon="⭐" text=" mCaptcha installation: integration of the mCaptcha widget to a service." >}}
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To help webmasters correctly configure difficult factors, we are
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building a feedback loop which would gather performance statistics from
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voluntary mCaptcha installations and make them available to other
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mCaptcha installations. The performance statistics can be used by all
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mCaptcha instances to automatically optimize an installation. We are
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calling this the mCaptcha net.
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## Participation is optional
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Participation in the mCaptcha net is disabled by default and is
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optional as it has privacy implications: it will reveal the
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existence of an mCaptcha instance.
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The admins of mCaptcha instances can choose to upload truly anonymous
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PoW performance statistics to a number of [mCaptcha/survey](https://git.batsense.net/mCaptcha/survey) instances.
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The data uploaded is public and so is accessible to all mCaptcha
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instances.
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We also offer opt-in controls at installation level:
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{{% img src="installation-level-opt-in.png" alt="A screenshot of the 'add sitekey' form on the mCaptcha dashboard with a checkbox for anonymously publishing performance statistics. It is not checked by default." caption="Add sitekey form on the mCaptcha dashboard with a checkbox for anonymously publishing performance statistics. It is not checked by default." %}}
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## Ensuring anonymity
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mCaptcha doesn't fingerprint its users. Performance parameters include:
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1. Time taken to generate PoW
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2. The difficulty factor for which the PoW was computed
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3. Type of client library used.
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```json
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"time":14,
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"difficulty_factor":50000,
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"worker_type":"wasm"
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```
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This doesn't include the usual fingerprinting parameters like
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User-Agent, cookies, and IP address. Additionally, we use pseudo IDs
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at both mCaptcha/mCaptcha and mCaptcha/survey to avoid exposing installations.
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{{% img src="working-rpc.png" alt="A screenshot of a tmux window with logs of mCaptcha/mCaptcha and mCapctha/survey showing both of them talking to eachother" caption="mCaptcha/mCaptcha uploading performance statistics to a mCaptcha/survey instance" %}}
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## Status
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We now have performance statistics uploads to mCaptcha/survey instances
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working. Pull request [mCaptcha/mCaptcha#92](https://github.com/mCaptcha/mCaptcha/pull/92)
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added abilities to mCaptcha to upload statistics to mCaptcha/survey instances and
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[mCaptcha/survey#40](https://git.batsense.net/mCaptcha/survey/pulls/17) enable survey to process the uploaded data. We will soon build a
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self-tuning algorithm within mCaptcha to use this data and optimize
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installations automatically.
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