+8.1.2 Usability Considerations by Authenticator Type
---+8.1.2.1 Passwords
---+8.1.2.2 Look-Up Secrets
---+8.1.2.3 Out-of-Band
---+8.1.2.4 Single-Factor OTP
---+8.1.2.5 Multi-Factor OTP
---+8.1.2.6 Single-Factor Cryptographic Authenticator
---+8.1.2.7 Multi-Factor Cryptographic Authenticator
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8.1.2 Usability Considerations by Authenticator Type
The following sections describe other usability considerations that are specific to particular authenticator types.
1. Overzicht
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Standaard |
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8.1.2.1 Passwords
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Typical Usage Users often manually input the password (sometimes referred to as a passphrase or PIN). Alternatively, they may use a password manager to select a secure password and maintain distinct passwords for each authenticated service. The use of distinct passwords is important to avoid “password stuffing” attacks in which an attacker uses a compromised password from one site to access the user’s account on other sites. Agencies should carefully evaluate password managers before making recommendations or mandates to confirm that they meet expectations for secure implementation. Usability considerations for typical usage without a password manager include:
Memorability of the password
The likelihood of a recall failure increases if there are more items for users to remember. With fewer passwords, users can more easily recall the specific password needed for a particular RP.
The memory burden is greater for a less frequently used password.
Usability considerations for typical usage with a password manager include:
Ease of entry
Support autofill functionality to allow for the safe retrieval of secrets from password managers.
Support copy and paste functionality in fields for entering passwords, including passphrases.
Intermittent Events Usability considerations for intermittent events include:
When users create and change passwords
Clearly communicate information on how to create and change passwords.
Clearly communicate password requirements, as specified in Sec. 3.1.1. Allow at least 64 characters in length to support the use of passphrases. Encourage users to make passwords as lengthy as they want and use any characters that they like (including spaces) to aid memorization. Ensure that user interfaces support sufficient password lengths.
Do not impose other composition rules (e.g., mixtures of different character types) on passwords.
Do not require that passwords be changed arbitrarily (e.g., periodically) unless there is a user request or evidence of authenticator compromise (see Sec. 3.1.1).
Provide clear, meaningful, and actionable feedback when chosen passwords are rejected (e.g., when it appears on a “blocklist” of unacceptable passwords or has been used previously).
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8.1.2.2 Look-Up Secrets
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Typical Usage Subscribers use a printed or electronic authenticator to look up the appropriate secrets needed to respond to a verifier’s prompt. For example, a user may be asked to provide a specific subset of the numeric or character strings printed on a card in table format. Usability considerations for typical usage include the following:
User experience during entry of look-up secrets
Consider the complexity and size of the prompts. There are greater usability implications with larger subsets of secrets that a user is prompted to look up. Both the cognitive workload and physical difficulty for entry should be considered.
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8.1.2.3 Out-of-Band
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Typical Usage Out-of-band authentication requires that users have access to a primary and secondary communication channel. Usability considerations for typical usage include the following:
Notify users of the receipt of a secret on a lockable device. If the out-of-band device is locked, authentication to the device should be required to access the secret.
Depending on the implementation, consider form-factor constraints, which are particularly problematic when users must enter text on mobile devices. Providing larger touch areas will improve usability for entering secrets on mobile devices.
Consider offering features that do not require text entry on mobile devices (e.g., a copy and paste feature), which are particularly helpful when the primary and secondary channels are on the same device. For example, it is difficult for users to transfer the authentication secret manually using a smartphone because they must switch back and forth — potentially multiple times — between the out-of-band application and the primary channel.
Messages and notifications to out-of-band devices should contain contextual information for the user, such as the name of the service being accessed.
Out-of-band messages should be delivered in a consistent manner and style to help the subscriber identify potentially suspicious authentication requests.
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8.1.2.4 Single-Factor OTP
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Typical Usage Users access the OTP generated by the single-factor OTP authenticator. The authenticator output is typically displayed on the authenticator, and the user enters it during the session being authenticated. Usability considerations for typical usage include the following:
Authenticator output allows at least one minute between changes but ideally allows users two full minutes, as specified in Sec. 3.1.4.1. Users need adequate time to enter the authenticator output, including looking back and forth between the single-factor OTP authenticator and the entry screen.
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8.1.2.5 Multi-Factor OTP
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Typical Usage Users access the OTP generated by the multi-factor OTP authenticator through a second authentication factor. The OTP is typically displayed on the device, and the user manually enters it during the session being authenticated. The second authentication factor may be achieved through some kind of integral entry pad to enter a password or an integral biometric (e.g., fingerprint) reader. Usability considerations for the additional factor also apply (see Sec. 8.1.2.1 for passwords and Sec. 8.1.4 for biometrics used in multi-factor authenticators). Usability considerations for typical usage include:
User experience during manual entry of the authenticator output
For time-based OTPs, provide a grace period in addition to the time during which the OTP is displayed. Users need adequate time to enter the authenticator output, including looking back and forth between the multi-factor OTP authenticator and the entry screen.
Consider form-factor constraints if users must unlock the multi-factor OTP authenticator via an integral entry pad or enter the authenticator output on mobile devices. Typing on small devices is significantly more error-prone and time-consuming than typing on a traditional keyboard. Providing larger touch areas improves usability for unlocking the multi-factor OTP authenticator or entering the authenticator output on mobile devices.
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8.1.2.6 Single-Factor Cryptographic Authenticator
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Typical Usage Users authenticate by proving possession and control of the cryptographic key. Usability considerations for typical usage include the following:
Give cryptographic keys appropriately descriptive names that are meaningful to users so that they can recognize and recall which cryptographic key to use for which authentication task. This prevents users from having to deal with multiple similarly and ambiguously named cryptographic keys. Requiring the user to select from multiple cryptographic keys on smaller mobile devices may be particularly problematic if the names of the cryptographic keys are shortened due to reduced screen sizes.
Requiring a physical input (e.g., pressing a button) to operate a single-factor cryptographic authenticator could pose usability difficulties. For example, some USB ports are located on the back of computers, making it difficult for users to reach the port.
For connected authenticators, the limited availability of a direct computer interface (e.g., USB port) could pose usability difficulties. For example, laptop computers often have a limited number of USB ports, which may force users to unplug other USB peripherals to use the authenticator.
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8.1.2.7 Multi-Factor Cryptographic Authenticator
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Typical Usage To authenticate, users prove possession and control of the cryptographic key and control of the activation factor. Usability considerations for the additional factor also apply (see Sec. 8.1.2.1 for passwords and Sec. 8.1.4 for biometrics used as activation factors). Usability considerations for typical usage include the following:
Give cryptographic keys appropriately descriptive names that are meaningful to users so that they can recognize and recall which cryptographic key to use for which authentication task. This prevents users from having to deal with multiple similarly and ambiguously named cryptographic keys. Selecting from multiple cryptographic keys on smaller mobile devices may be particularly problematic if the names of the cryptographic keys are shortened due to reduced screen sizes.
Do not require users to keep external multi-factor cryptographic authenticators connected following authentication. Users may forget to disconnect the authenticator when they are done with it (e.g., forgetting a smartcard in the smartcard reader and walking away from the computer).
Users need to be informed about whether the authenticator is required to stay connected or not.
For connected authenticators, the limited availability of a direct computer interface (e.g., USB port) could pose usability difficulties. For example, laptop computers often have a limited number of USB ports, which may force users to unplug other USB peripherals to use the authenticator.
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1.1 Referenties
1.2 Geïdentificeerde eisen
1.3 Gerelateerde regelingen
2. Geïdentificeerde eisen
3. Gerelateerde regelingen
Regelingen
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Regelgeving |
- NIST -
EN: Publications of the National Institute of Standards and Technology (NIST), U.S. Department of Commerce, https://www.nist.gov/, from their electronic versions (OSCAL; SP 800-63-4 from its HTML version, https://pages.nist.gov/800-63-4/). Works of NIST employees are not subject to copyright protection in the United States (17 U.S.C. § 105); the OSCAL content is dedicated to the public domain worldwide (CC0 1.0); outside the United States NIST grants the right to reprint its technical series publications in all formats (NIST copyright statement). Republished courtesy of the National Institute of Standards and Technology; each document names its citation. Divided into sections and converted into the GRCA format, the wording unchanged. Only the versions published by NIST are authoritative.
DE: Veröffentlichungen des National Institute of Standards and Technology (NIST), U.S. Department of Commerce, https://www.nist.gov/, aus ihren elektronischen Fassungen (OSCAL; SP 800-63-4 aus ihrer HTML-Fassung, https://pages.nist.gov/800-63-4/). Werke von NIST-Beschäftigten sind in den USA urheberrechtlich nicht geschützt (17 U.S.C. § 105); die OSCAL-Inhalte sind weltweit gemeinfrei gestellt (CC0 1.0); außerhalb der USA räumt das NIST das Recht ein, seine Technical-Series-Publikationen in allen Formaten neu zu veröffentlichen (Copyright-Hinweis des NIST). „Republished courtesy of the National Institute of Standards and Technology“; jedes Dokument nennt seine Zitierangabe. In Abschnitte aufgeteilt und in das GRCA-Format umgewandelt, der Wortlaut unverändert. Maßgeblich sind allein die vom NIST veröffentlichten Fassungen.
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