.. fips-specifics.rst .. _fips-specifics-label: =============================== YubiKey 5 FIPS Series Specifics =============================== .. _fips5-deploy-label: Deploying the YubiKey 5 FIPS Series ==================================== The YubiKey 5 FIPS Series keys are certified under FIPS 140-2 Level 1 and FIPS 140-2 Level 2. Keys in this series have two certificates, each corresponding to a different level of certification, but both certificates apply to the same keys. The YubiKey chipset is certified at FIPS 140-2 Physical Security Level 3. This provides both tamper-evidence and tamper-resistance. In turn, this means the YubiKey 5 FIPS Series keys can be used in an Overall Security Level 1 or 2 environment without issue. Depending on which certification the YubiKey 5 FIPS Series is being deployed under, there are different requirements for securing the various functions. To review the differences between the considerations and requirements for a FIPS 140-2 Level 1 authenticator and those for a FIPS 104-2 Level 2 authenticator, see :ref:`fips5-levels-label`. `NIST SP 800-63-B `_ provides guidance on the level required for your deployment. In cases where only Level 1 is required, the end-user experience with a YubiKey 5 FIPS Series is similar to that of a user with a key from the YubiKey 5 Series. The user experience with YubiKey 5 FIPS Series deployed under FIPS 140-2 Level 2 is more complicated. NIST classified the YubiKey 5 Series FIPS as "composite authenticators". As such, no device in this series can be taken out of the FIPS-approved mode after initialization without zeroing the function. This means that once the YubiKey is correctly configured, it remains in the correct configuration. This renders the ``--check-fips`` command unnecessary. If the crypto officer ensures that the YubiKey 5 Series FIPS devices are correctly configured at initialization, they remain in FIPS-approved mode. .. _fips-config-label: Configuring the YubiKey 5 FIPS Series under FIPS 140-2 Level 1 --------------------------------------------------------------- Without any configuration, the YubiKey 5 FIPS Series meets the requirements for the FIPS 140-2 Level 1 certification as an authenticator with FIPS-approved algorithms. Security Level 1 allows an authenticator to be used on a general purpose computing system using an unevaluated operating system. This can include computers or OSs that are configured in a FIPS-certified mode of operation, but which might not have extensive access controls or auditing features. Any function on the YubiKey may be used. The only non-approved algorithms are: * RSA 1024-bit keys * EdDSA keys * X25519 keys Configuring the YubiKey 5 FIPS Series under FIPS 140-2 Level 2 --------------------------------------------------------------- Security Level 2 includes all of the requirements for FIPS Level 1, but further enforces enhanced physical security mechanisms and a separation of functions with regard to role-based authentication. Security Level 2 allows an authenticator to be used on a general purpose computing system with an operating system that has been evaluated at `EAL2 `_ with role-based access control mechanisms and comprehensive auditing. The role-based authentication minimum requirement is that a cryptographic module authenticates the authorization of an operator to assume a specific role and perform a corresponding set of services. A Security Officer role is required for services such as importing or generating new credentials or programming new OTP secrets on a YubiKey. The User role covers the actual usage of programmed credentials for authentication. The Crypto Officer role is that of "a cryptographic officer [who] is authorized to perform cryptographic initialization and management functions on a CKMS [Cryptographic Key Management System] and its cryptographic modules." (Quote taken from `SP 800-130 (DOI) `_.) To act in an Overall Security Level 2 environment, a YubiKey must be configured in a FIPS-approved mode of operation or receive an exemption from the security auditor. .. Note:: To load key data over NFC requires a secure channel. For more information on Secure Channel (SCP03) in connection with YubiKeys, see the *YubiKey 5 Series Technical Manual*, `Secure Channel Technical Description `_. For more information on SCP03 requirements from NIST, see `NIST Special Publication 800-63C `_ and `NIST Special Publication 800-63B `_. For a YubiKey 5 FIPS Series to be operating as a security key in FIPS-approved mode, in a FIPS 140-2 Level 2 authenticator in a FIPS environment, all of the applications must be in a FIPS-approved operation mode. By default, not all of the applications on the YubiKey 5 FIPS Series are in FIPS operation mode. Before deploying the YubiKey 5 FIPS Series in a secured environment to end-users, the person with the crypto officer role must define and supervise an initialization and delivery process that ensures that each application on the YubiKey 5 FIPS Series is in a FIPS-approved operation mode. Every function of the YubiKey must require permissions defined by a role. In practice, this is accomplished by setting the access codes, management keys, passwords, PINs, etc. for every function on the YubiKey. To ensure that each application is in a FIPS-approved mode of operation, use the **YubiKey Manager (ykman)** Command Line Interface (CLI). .. include:: includes/ykman.rst :PIV: The PIV application has its credentials set to default values, and is therefore already in a FIPS-approved mode. :OTP: OATH and WebAuthn: To be in a FIPS-approved mode, the OTP, OATH and WebAuthn applications must have their respective credentials set. .. Note:: Using U2F is not allowed when the YubiKey 5 FIPS Series is deployed as a 140-2 Level 2 authenticator. .. Note:: It is highly recommended that all the credentials across all the applications be changed from the default values before the YubiKey 5 FIPS Series device is deployed to the end user, even if FIPS 140-2 Level 2 does not explicitly require it. .. _credential-values-label: Credentials and Permitted Values ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The table below lists the credentials required, allowed values, and credential owner for the supported applications. .. table:: +--------------------+-----------------+---------------------+----------------+ | Application | Credential | Permitted Values || Credential | | | | || Owner | +====================+=================+=====================+================+ || One Time Password || Access Code: | | | || (OTP) || OTP Slot 1 || 6 byte access codes| Crypto Officer | || || OTP Slot 2 || 6 byte access codes| | +--------------------+-----------------+---------------------+----------------+ | OATH || Authentication || 14-64 byte HMAC | Crypto Officer | | || Key || SHA1/SHA256 key | | +--------------------+-----------------+---------------------+----------------+ | PIV Smart Card |Management Key | 3-key TDES key | Crypto Officer | | +-----------------+---------------------+----------------+ | |PUK | 6-8 byte PIN | Crypto Officer | | +-----------------+---------------------+----------------+ | |PIN | 6-8 byte PIN || Authenticated | | | | || User | +--------------------+-----------------+---------------------+----------------+ | OpenPGP || User Password | 6‐127 byte PIN || Authenticated | | || (PW1) | || User | | +-----------------+---------------------+----------------+ | || Admin Password | 8‐127 byte PIN | Crypto Officer | | || (PW3) | | | +--------------------+-----------------+---------------------+----------------+ | WebAuthn |PIN | 6 to 32 byte PIN || Authenticated | | | | || User | +--------------------+-----------------+---------------------+----------------+ The instructions for the individual applications are provided in the following topics: * :ref:`fips5-otp-label` * :ref:`fips5-oath-label` * :ref:`fips5-piv-label` * :ref:`yk5-apps-openpgp-label`: :ref:`yk5-apps-label` * :ref:`fips5-fido-label` (WebAuthn) ---- .. _fips5-otp-label: OTP: FIPS 140-2 with YubiKey 5 FIPS Series =========================================== The OTP application provides two programmable slots, each of which can hold one of the types of credentials listed below. A Yubico OTP credential is programmed to slot 1 during manufacturing. 1. Trigger the YubiKey to produce the credential in the first slot by briefly touching the metal contact of the YubiKey. 2. If a credential has been programmed to the second slot, trigger the YubiKey to produce it by touching the contact for 3 seconds. Output is sent as a series of keystrokes from a virtual keyboard. Yubico OTP ----------- `Yubico OTP `_ is a strong authentication mechanism that is supported by all YubiKey 5 FIPS Series. Yubico OTP can be used as the second factor in a two-factor authentication (2FA) scheme or on its own, providing single-factor authentication. The OTP generated by the YubiKey has two parts: the first 12 characters are the public identity that a validation server uses to link to a user, the remaining 32 characters are the unique passcode that is changed every time an OTP is generated. The character representation of the Yubico OTP is designed to handle a variety of keyboard layouts. It is crucial that the same code is generated if a YubiKey is inserted into a German computer with a QWERTZ layout, a French one with an AZERTY layout, or a US one with a QWERTY layout. The Modified Hexadecimal (Modhex) coding, was invented by Yubico to use only specific characters to ensure that the YubiKey works with the maximum number of keyboard layouts. USB keyboards send their keystrokes through “scan codes” rather than actual characters. The device, where the YubiKey is connected, translates the scan codes into keystrokes. OTP Deployment --------------- The YubiKey 5 FIPS Series OTP application supports two independent OTP configurations, known as OTP slots. The OTP slots can be configured to output an OTP created with the Yubico OTP or OATH-HOTP algorithm, a HMAC-SHA1 hashed response to a provided challenge, or a static password. A short touch (1~3 seconds) on the gold contact triggers the output of OTP slot 1. A long touch (+3 seconds) triggers the output of OTP slot 2. A 6-byte access code can be set on slot 1 and slot 2 independently. Once set, the OTP slot’s access code is required when modifying, overwriting, or deleting the configuration on the respective OTP slot. By default, the YubiKey is shipped without any access code. FIPS 140-2 Level 2: Placing the OTP Application in FIPS-approved Mode ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Each OTP slot must be locked down with an access code for the YubiKey 5 FIPS Series OTP application to be in a FIPS-approved mode of operation. By default, no access codes is set for either slot. * An access code must be applied to each OTP slot, either: * When writing a new configuration or * By updating an existing configuration in an OTP slot. * An access code cannot be applied to an empty OTP slot. * To secure an unused OTP slot, use a blank OTP configuration with an access code. * YubiKey 5 FIPS Series devices must either be deployed with * The OTP slots already set with an access code, or * An OTP application or service that configures the access code on both slots on enrollment. * The OTP slot access codes must be archived so that only the crypto officer alone can access them. Access codes are required when resetting the OTP application. Using the YubiKey Manager to Set Access Codes ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; The crypto officer can set an access code to the OTP slots using the YubiKey Manager Command Line Interface (CLI). .. include:: includes/ykman.rst To **apply an access code to a configuration** using the YubiKey Manager CLI, include the flag ``--new-access-code=`` in the OTP configuration string. Use the command: ``ykman otp settings --new-access-code= [OTP Slot]`` where - ```` is the access code to be set. For the characteristics of the access code, see :ref:`credential-values-label`. ``[OTP Slot]`` is either ``1`` or ``2`` corresponding to the OTP configuration being applied to OTP slot 1 or OTP slot 2. For full details on setting an OTP configuration using the YubiKey Manager CLI, see the `section of that name in the YubiKey Manager CLI & GUI Guide `_. To **fill a blank OTP slot** with a default configuration, use the command: ``ykman otp chalresp --generate [OTP Slot]`` where ``[OTP Slot]`` is either ``1`` or ``2`` corresponding to the OTP configuration being applied to OTP slot 1 or OTP slot 2. ---- .. _fips5-oath-label: OATH: FIPS 140-2 with YubiKey 5 FIPS Series ============================================ The YubiKey 5 FIPS OATH application can store up to 32 OATH credentials, either OATH-TOTP (time-based) or OATH-HOTP (counter-based), as defined in the `OATH specification `_. These credentials are separate from those stored in the OTP application. They can only be accessed through the CCID channel. When an OATH-HOTP credential is programmed, the OTP is generated using the standard `RFC 4226 `_ HOTP algorithm and the YubiKey automatically types the OTP. Optionally, the OTP can be prefixed by a public identity, conforming to the `openauthentication.org Token Identifier Specification `_. To manage the OATH credentials and read the OTPs generated by the YubiKey, requires the `Yubico Authenticator `_. The Yubico Authenticator is supported on Windows, Linux, macOS, Android and iOS. FIPS 140-2 Level 2: Placing the OATH Application in FIPS-approved Mode ----------------------------------------------------------------------- For an application to be in a FIPS-approved mode requires an Authentication Key that protects access to the YubiKey 5 FIPS Series OATH application. To get the permitted values for the following operation, see :ref:`credential-values-label`. The crypto officer can set the Authentication Key using the YubiKey Manager Command Line Interface (CLI). .. include:: includes/ykman.rst To set an Authentication Key using the YubiKey Manager CLI, use the command: ``ykman oath access change -n `` where ```` is the Authentication Key to be set. ---- .. _fips5-fido-label: FIDO: FIPS 140-2 with YubiKey 5 FIPS Series ============================================ FIDO U2F --------- `FIDO U2F `_ is an open standard that provides strong, phishing-resistant two-factor authentication for web services using public key cryptography. U2F does not require any special drivers or configuration to use, just a compatible web browser. The U2F application on the YubiKey can be associated with an unlimited number of U2F sites. FIDO2 ------ Like FIDO U2F, the `FIDO2 `_ standard offers the same high level of security, as it is based on public key cryptography. In addition to providing phishing resistant two-factor authentication, the FIDO2 application on the YubiKey enables storing resident credentials. Resident credentials can accommodate the username and other data, this enables truly passwordless authentication. Keys in the YubiKey 5 FIPS Series can hold up to 25 resident keys. Locking FIDO2 Credentials ~~~~~~~~~~~~~~~~~~~~~~~~~~ Resident credentials can be protected by a PIN for two-factor authentication. * The FIDO2 PIN must be between 6 and 63 alphanumeric characters in length. * Once a FIDO2 PIN is set, it can be changed but it cannot be removed without resetting the FIDO2 application. * After 3 incorrect PIN entries, power cycle the FIDO2 application. This resets the FIDO2 application and restores functionality. * If the PIN is entered incorrectly 8 times in a row, the FIDO2 application locks and FIDO2 authentication is no longer possible. .. Note:: Resetting the FIDO2 application also resets the U2F key. Any site that you registered the YubiKey with using U2F need to be re-registered. U2F is not compatible with FIPS 140-2 Level 2. .. Note:: The YubiKey 5 FIPS Series supports FIOD2 credential management, this includes enabling the option to selectively delete resident keys. See the `Enhancements to FIDO 2 Support `_ for details. The rules governing FIPS-certified environments forbid the use of the following features of the YubiKey 5 FIPS Series: * The P-224 curve * Credential registration over NFC. Default Values ;;;;;;;;;;;;;;; PIN: None set. Placing the WebAuthn Application in FIPS-approved Mode -------------------------------------------------------- For the YubiKey WebAuthn application to be in a FIPS approved mode of operation, set a WebAuthn PIN. By default, no WebAuthn PIN is set. To **set or change the WebAuthn PIN**, use the YubiKey Manager Command Line Interface (CLI). To set an WebAuthn PIN, on the YubiKey Manager CLI, use the command: ``ykman fido access change-pin -n`` where ```` is the WebAuthn PIN to be set. See :ref:`credential-values-label` for PIN requirements. U2F ~~~ The YubiKey 5 U2F FIPS application cannot be used in FIPS 140-2 Level 2 mode. Instead of the U2F functionality, use the FIDO WebAuthn application. FIPS-certified services should not call the U2F functionality; nonetheless, disable the U2F function on the YubiKey to ensure it is not used. To disable U2F over USB and NFC, use the commands: .. code-block:: bash ykman config usb -dU2F ykman config nfc -dU2F To **ensure users cannot enable U2F**, secure access to it with a management lock code. To set this code, use the command: ``ykman config set-lock-code -n`` where ```` is a 16 byte (32 character) hex value. .. Note:: The lock code prevents anyone without it from changing the functions that are accessible over NFC or USB. The lock code cannot be recovered if lost. Losing the lock code makes the YubiKey permanently inaccessible. ---- .. _fips5-piv-label: PIV: FIPS 140-2 with YubiKey 5 FIPS Series =========================================== The YubiKey 5 FIPS Series provides a PIV-compatible smart card application. PIV or FIPS 201, is a US government standard that enables RSA or ECC sign and encrypt operations using a private key stored on a smart card through common interfaces like PKCS#11. On Windows, the smart card functionality can be extended with the `YubiKey Smart Card Minidriver `_. The YubiKey Smart Card Minidriver is not available for Android, Linux, macOS or iOS. Keys in the YubiKey 5 FIPS Series support extended APDUs, extended `Answer To Reset (ATR)`, and `Answer To Select` (ATS). Using the PIV APDUs on iOS requires the Yubico iOS SDK. For YubiKey 5 FIPS Series, some exceptions apply: * Do not use non-NIST-approved curves * Do not use the following keys: * RSA 1,024-bit * 3,072-bit keys. This applies to Attestation as well. * PIN policy = ``none`` cannot be used. Select either ``once`` or ``always``. Default Values ---------------- * PIN: 123456 * PUK: 12345678 * Management Key (3DES): ``010203040506070801020304050607080102030405060708`` Supported Algorithms ---------------------- The YubiKey 5 FIPS Series supports the following algorithms on the PIV smart card application. * RSA 1024 * RSA 2048 * ECC P-256 * ECC P-384 Policies ---------- PIN Policy ~~~~~~~~~~~ To specify how often the PIN needs to be entered for access to the credential in a given slot, set a PIN policy for that slot. This policy must be set upon key generation or import; it cannot be changed later. Touch Policy ~~~~~~~~~~~~~ In addition to requiring the PIN, the YubiKey can require a physical touch on the metal contact. Similar to the PIN policy, the touch policy must be set upon key generation or import. Slot Information ----------------- The keys and certificates for the smart card application are stored in slots. The PIN policies are the defaults, before they are overridden with a custom PIN policy. **These slots are separate from the programmable slots in the OTP application.** Slot 9a: PIV Authentication ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ This certificate and its associated private key is used to authenticate the card and the cardholder. This slot is used for system login, etc.. To perform any private key operations, the end user PIN is required. Once the correct PIN has been provided, multiple private key operations may be performed without additional cardholder consent. Slot 9c: Digital Signature ~~~~~~~~~~~~~~~~~~~~~~~~~~~ This certificate and its associated private key is used for digital signatures on documents, email, files, and executable signings. The end user PIN is required perform any private key operations. The PIN must be submitted immediately before each sign operation to ensure cardholder participation for every digital signature generated. Slot 9d: Key Management ~~~~~~~~~~~~~~~~~~~~~~~~ This certificate and its associated private key is used for encryption to assure confidentiality. This slot is used for encrypting emails or files. The end user PIN is required to perform any private key operations. Once the correct PIN has been provided, multiple private key operations may be performed without additional cardholder consent. Slot 9e: Card Authentication ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ This certificate and its associated private key is used to support additional physical access applications, such as providing physical access to buildings through PIV-enabled door locks. The end user PIN is NOT required to perform private key operations for this slot. Slots 82-95: Retired Key Management ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ These slots are meant for previously used key management keys for decrypting earlier encrypted documents or emails. Slot f9: Attestation ~~~~~~~~~~~~~~~~~~~~~~ This slot is used only for attestation of other keys generated on device with instruction F9. This slot is not cleared on reset, but can be overwritten. Attestation ------------ Attestation enables you to verify that a key on the smart card application was generated on the YubiKey rather than being imported. If the key was generated on the YubiKey, an X.509 certificate was created for the key. Included in the certificate are the following extensions that provide information about the YubiKey. Firmware ~~~~~~~~~ ``1.3.6.1.4.1.41482.3.3``: Firmware version, encoded as three bytes. For example, 050100 indicates firmware version 5.1.0. Serial Number ~~~~~~~~~~~~~~ * ``1.3.6.1.4.1.41482.3.7``: Serial number of the YubiKey, encoded as an integer. * ``1.3.6.1.4.1.41482.3.8``: Two bytes, the first encoding the PIN policy and the second encoding the touch policy.   PIN Policy ;;;;;;;;;;; * 01 - never require PIN * 02 - require PIN once per session * 03 - always require PIN. Touch Policy ;;;;;;;;;;;;; * 01 - never require touch * 02 - always require touch * 03 - cache touch for 15 seconds. Form Factor ;;;;;;;;;;;; ``1.3.6.1.4.1.41482.3.9``: YubiKey’s form factor, encoded as a one-byte octet-string.   * USB-A Keychain: 0x01 * USB-A Nano: 0x02 * USB-C Keychain: 0x03 * USB-C Nano: 0x04 * USB-C and Lightning®: 0x05 * Undefined: 0x00 New in YubiKey 5 FIPS Series ----------------------------- ATR and ATS ~~~~~~~~~~~~ The ATR has been changed from “Yubikey 4” to “YubiKey” and adds support for ATS. PIV Attestation Root CA ~~~~~~~~~~~~~~~~~~~~~~~~~ There are no changes in PIV attestation between the YubiKey 5 Series and the YubiKey 5 FIPS Series. You can find the root certification authority on the `PIV attestation `_ page. PIV/Smart Card Deployment -------------------------- The YubiKey 5 FIPS Series PIV application implements a PIV-compatible standard as defined in the `NIST SP 800-73-4 `_ publication. Access to functions on the YubiKey 5 FIPS Series PIV application is restricted by the management key, the PIN, and the PUK. The management key is used for: * Importing or generating asymmetric key pairs * Importing x.509 certificates and associated information * Setting the retry counters for PIN (also requires PIN) and PUK The PIN is used to: * Perform cryptographic operations using private keys * Change the PIN The PUK is used to: * Unblock and set a new PIN for a blocked PIN * Change the PUK The YubiKey 5 FIPS Series PIV application has the default values: • Management Key ``(010203040506070801020304050607080102030405060708)`` • PIN ``(123456)`` • PUK ``(12345678)`` FIPS 140-2 Level 2: Placing the PIV Application in FIPS-approved Mode ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ To place the YubiKey 5 FIPS Series PIV application in the FIPS-approved mode of operation, change the default management key, PIN, and PUK. YubiKey 5 FIPS Series devices should be deployed using a credential management tool like Microsoft ADCS with YubiKey minidriver or a third party tool. The credential management tool replaces the default values by automatically setting a random value for the management key and PUK and allows the end user to define the PIN. If the YubiKey 5 FIPS Series PIV application is not being managed with a credential management tool, the management key, PIN, and PUK must be changed by the crypto officer. To do so, use the YubiKey Manager (ykman). .. include:: includes/ykman.rst To **change the management key**, use the command: .. code-block:: bash ykman piv access change-management-key -m010203040506070801020304050607080102030405060708 / -a -n where - ```` is the new management key ```` is the key type [Triple-DES, AES-128, AES-192 or AES-256]. To **change the PIN**, use the command: .. code-block:: bash ykman piv access change-pin -P123456 -n where ```` is the new PIN. To **change the PUK**, use the command: .. code-block:: bash ykman piv access change-puk -p12345678 -n where ```` is the new PUK. ---- .. _fips5-levels-label: FIPS Level 1 vs FIPS Level 2 ============================= The YubiKey 5 FIPS Series is certified in two modes of operations: * Configuration which meets the requirements for FIPS Level 1 * More restricted configuration that meets the requirements for FIPS Level 2. The FIPS Level 2 configuration renders keys in the YubiKey 5 FIPS Series capable of being a component in a framework meeting the highest levels of authentication assurance. However, not every deployment requires this level of security. In cases where a FIPS-certified device is required, but a lower level of assurance is acceptable, the FIPS Level 1 configuration can be used. This provides a user experience like the standard YubiKey 5 Series user experience. FIPS Initialization Comparison: Level 1 vs Level 2 --------------------------------------------------- The FIPS Level 2 requirements include all the those for Level 1. Therefore the FIPS Level 2 column in the table below lists only the differences. .. table:: +------------+------------------------------+-------------------------------------+ || YubiKey | | | || Function |FIPS Level 1 |FIPS Level 2 | +============+==============================+=====================================+ || Touch- || If writing a configuration || Set Access code for both OTP slots.| || Triggered || to a slot over NFC, use a || If updating a configuration of | || OTP || secure channel. || either OTP slot or the NDEF | || || || behavior, use a secure channel. | +------------+------------------------------+-------------------------------------+ | OATH || If writing a credential || Set the Management key. | | || over NFC, use a secure || When setting the Management key | | || channel. || over USB or NFC, use a secure | | || || channel. | | || || When writing a credential over USB | | || || or NFC, use a secure channel. | +------------+------------------------------+-------------------------------------+ | PIV || If importing a key or || Change Management key, PIN and PUK | | || setting the management key, || from default values. | | || use a secure channel. || For any operation with the PIV | | || || function over NFC, use a secure | | || || channel. | +------------+------------------------------+-------------------------------------+ | U2F | No additional requirements || Must be not be used. | | | || Recommendation: Disable and use | | | || the FIDO2 function instead. | +------------+------------------------------+-------------------------------------+ | FIDO2 | No additional requirements || Set a PIN. | | | || Set Credential Protection to | | | || level 2 for all discoverable | | | || credentials. | | | || Credential Registration is not | | | || allowed over NFC. | +------------+------------------------------+-------------------------------------+ || Secure || Change the default | No additional requirements | || Channel || transport keys from default | | +------------+------------------------------+-------------------------------------+ For more information on secure channel requirements from NIST, see NIST SP 800-63-C and NIST SP 800-63B. ---- Click for `Yubico Support `_.