87 lines
3.4 KiB
Markdown
87 lines
3.4 KiB
Markdown
---
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title: "Terminology"
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description: "Information about terminology used in mCaptcha, some of which unique to the project"
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lead: ""
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date: 2022-07-27T08:48:45+00:00
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lastmod: 2020-07-27T08:48:45+00:00
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draft: false
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menu:
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docs:
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parent: "Webmasters"
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---
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## Authorization token
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When a visitor solves the CAPTCHA and sends their solution to an
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mCaptcha instance, the solution will be verified for correctness. If the
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solution is correct, mCaptcha will return a single use authorization token.
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This authorization token should be attached to the visitor's requited to the
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protected service and the protected service should validity of the
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authorization token with the mCaptcha instance and only allow authorization to
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protected resource if the authorization token is valid.
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## Cooldown Period
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mCaptcha implements leaky bucket algorithm to measure
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current traffic levels. Cooldown period specifies the leak or the time
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after which a visitor addition is decremented.
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For instance, if initial traffic level is 0 and a user visits one
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second later, the traffic level will be incremented to 1. Now, if the
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cooldown period is set to 30 seconds, the traffic level will be
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decremented after 30 seconds. So after 30 seconds, the traffic level will
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go from 1 to 0.
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## Difficulty Factor
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Difficulty factor determines the time it takes to solve a CAPTCHA. The
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higher the difficulty factor, the longer it will take to generate a
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proof of work for it to solve the CAPTCHA.
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mCaptcha's proof of work based mechanism makes it highly accessible to
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people with special needs but it is important to choose the difficulty factor
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with care as very high difficulty factors will make the CAPTCHA
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inaccessible to users on slow devices.
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## Sitekey
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Site key is a unique identifier associated with CAPTCHA configurations
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created on mCaptcha. It is required to integrate a CAPTCHA with your
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website.
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## Visitor Threshold
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mCaptcha's variable difficulty factor mechanism requires a website's traffic
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statistics be split into levels, so that it can deploy the right
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difficulty factor for each level.
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Visitor threshold is used to traffic into levels and mCaptcha accepts a
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difficulty configuration for each of these levels. When current traffic
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exceeds a difficulty factor, mCaptcha will increase the difficulty
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factor to the next configured level.
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For instance, consider the configuration given below:
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- Cool down period: 30 seconds
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| Level | Difficulty Factor | Visitor Threshold |
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| ----- | ----------------- | ----------------- |
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| 1 | 5,000 | 2,000 |
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| 2 | 50,000 | 5,000 |
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| 3 | 500,000 | 10,000 |
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| 4 | 5,000,000 | 15,000 |
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If the website sees 2,000 requests in a 30 second window, level 1
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difficulty factor(5,000) will be deployed. If the traffic increases to
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5,000 requests in a 30 second window, then difficulty factor will be
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upgraded to level 2(50,000). Likewise 10,000 and 15,000 requests over 30
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seconds will result in difficulty factor being upgraded to 500,000 and
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5,000,000 respectively.
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Visitor threshold is how mCaptcha determines which difficulty factor
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level to deploy. mCaptcha uses leaky bucket algorithm to keep the
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visitor threshold constantly updated within the configured cool down
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period. So, at any given moment the, the current visitor level will be
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the amount of traffic that was served in the cool down period specified.
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