56 lines
1.8 KiB
Markdown
56 lines
1.8 KiB
Markdown
---
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layout: default
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title: One-Time Password
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parent: Configuration
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nav_order: 4
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---
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# One-Time Password
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Authelia uses time based one-time passwords as the OTP method. You have
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the option to tune the settings of the TOTP generation and you can see a
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full example of TOTP configuration below, as well as sections describing them.
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```yaml
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totp:
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issuer: authelia.com
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period: 30
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skew: 1
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```
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## Issuer
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Applications generating one-time passwords usually display an issuer to
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differentiate applications registered by the user.
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Authelia allows customisation of the issuer to differentiate the entry created
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by Authelia from others.
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## Period and Skew
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The period and skew configuration parameters affect each other. The default values are
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a period of 30 and a skew of 1. It is highly recommended you do not change these unless
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you wish to set skew to 0.
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The way you configure these affects security by changing the length of time a one-time
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password is valid for. The formula to calculate the effective validity period is
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`period + (period * skew * 2)`. For example period 30 and skew 1 would result in 90
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seconds of validity, and period 30 and skew 2 would result in 150 seconds of validity.
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### Period
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Configures the period of time in seconds a one-time password is current for. It is important
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to note that changing this value will require your users to register their application again.
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It is recommended to keep this value set to 30, the minimum is 1.
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### Skew
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Configures the number of one-time passwords either side of the current one that are
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considered valid, each time you increase this it makes two more one-time passwords valid.
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For example the default of 1 has a total of 3 keys valid. A value of 2 has 5 one-time passwords
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valid.
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It is recommended to keep this value set to 0 or 1, the minimum is 0. |