x firmware line. YubiKey slot 2 is properly configured for HMAC-SHA1 challenge-response with YubiKey Personalization Tool. Perform a challenge-response style operation using either YubicoOTP or HMAC-SHA1 against a configured YubiKey slot. So I use my database file, master password, and Yubikey challenge-response to unlock the database, all good. I think. In order to use OnlyKey and Yubikey interchangeably both must have the same HMAC key set. Scan yubikey but fails. I suspect that the yubico personalization tool always sends a 64 byte buffer to the yubikey. The driver module defines the interface for communication with an. I transferred the KeePass. After the OTP is verified, your application uses the public identity to validate that the YubiKey belongs to the user. If they gained access to your YubiKey then they could use it there and then to decrypt your. Yubikey to secure your accounts. 5 beta 01 and key driver 0. Joined: Wed Mar 15, 2017 9:15 am. Dr_Bel_Arvardan • 22 days ago. debinitialization: add a secret to the Yubikey (HMAC-SHA1 Challenge-Response) factor one is the challenge you need to enter manually during boot (it gets sha256sumed before sending it to the Yubikey) the second factor is the response calculated by the Yubikey ; challenge and response are concatenated and added as a. For a new KeePass database, on the Create Composite Master Key screen, enter your desired master password, then check Show expert options, check Key file / provider, select YubiKey challenge-response, and click OK. The U2F application can hold an unlimited number of U2F. A Security Key's real-time challenge-response protocol protects against phishing attacks. A YubiKey with configuration slot 2 available; YubiKey Manager; KeePass version 2 (version should be 2. This credential can also be set to require a touch on the metal contact before the response is sent to the requesting software. (Edit: also tested with newest version April 2022) Note While the original KeePass and KeePassXC use the same database format, they implement the challenge-response mode differently. Weak to phishing like all forms of otp though. This plugin leverages the open source yubikey libraries to implement the HMAC-SHA1 challenge-response functionality in Keepass. Which is probably the biggest danger, really. Existing yubikey challenge-response and keyfiles will be untouched. USING KeeChallenge works using the HMAC-SHA1 challenge response functionality built into the Yubikey. A YubiKey has two slots (Short Touch and Long Touch). In Keepass2Android I was getting the Invalid Composite Key error, until I followed these instructions found in an issue on Github. Perform a challenge-response style operation using either YubicoOTP or HMAC-SHA1 against a configured YubiKey slot. Also, as another reviewer mentioned, make sure the Encryption Algorithm is set to AES-256 and the Key. In the challenge-response mode, the application on your system can send a challenge to the YubiKey at regular intervals of time and the YubiKey if present in the USB port will respond to that challenge. The text was updated successfully, but these errors were encountered:. 40 on Windows 10. The majority difference is instead of a USB-A connector it has a USB-C and Lightning connector. Context. The YubiKey 5C NFC combines both USB-C and NFC connections on a single security key, making it the perfect authentication solution to work across any range of modern devices and leading platforms such as iOS, Android, Windows, macOS, and Linux. AppImage version works fine. I have the database secured with a password + yubikey challenge-response (no touch required). If button press is configured, please note you will have to press the YubiKey twice when logging in. The main issue stems from the fact that the verifiableFactors solely include the authenticator ID but not the credential ID. install software for the YubiKey, configure the YubiKey for the Challenge-Response mode, store the password for YubiKey Login and the Challenge-Response secret in dom0, enable YubiKey authentication for every service you want to use it for. ), and via NFC for NFC-enabled YubiKeys. It will be concatenated with the challenge and used as your LUKS encrypted volume passphrase for a total length of 104 (64+40) bytes. 4. Apps supporting it include e. You will have done this if you used the Windows Logon Tool or Mac Logon Tool. 0 from the DMG, it only lists "Autotype". If you choose to authenticate locally then you configure slot 2 of your Yubikey in challenge response mode ( following the other tutorial ) The password prompt depends on how you configure sshd / pam _____-Tom. To do this. The LastPass Mobile Device Application supports YubiKey two-factor authentication via both direct connection (USB, Lightning, etc. Unfortunately the development for the personalization tools has stopped, is there an alternative tool to enable the challenge response?The Yubico PAM module first verifies the username with corresponding YubiKey token id as configured in the . {"payload":{"allShortcutsEnabled":false,"fileTree":{"examples":{"items":[{"name":"configure_neo_ndef","path":"examples/configure_neo_ndef","contentType":"file. In my experience you can not use YubiChallenge with Keepass2Android - it clashes with its internal Yubikey Neo support, each stealing the NFC focus from the other. KeeChallenge works using the HMAC-SHA1 challenge response functionality built into the Yubikey. 2 and 2x YubiKey 5 NFC with firmware v5. Use the KeeChallenge plugin with Keepass2 on the Desktop, and the internal Challenge-Response method in. 2 and later. 1 Introduction This guide covers how to secure a local Linux login using the HMAC-SHA1 Challenge-Response feature on YubiKeys. open the saved config of your original key. Yubikey Personalization Tool). The HMACSHA1 response is always 20 bytes but the longer challenge may be used by other apps. The key pair is generated in the device’s tamper-resistant execution environment, from where k priv cannot leave. insert your new key. Instead they open the file browser dialogue. I use KeepassXC as my TOTP and I secure KeepassXC with Yubikey's challenge response. OATH Challenge-Response Algorithm: Developed by the Initiative for Open Authentication, OCRA is a cryptographically strong challenge-response authentication protocol. Yes, it is possible. These features are listed below. Open it up with KeePass2Android, select master key type (password + challenge-response), type in password, but. Click Challenge-Response 3. The last 32 characters of the string is the unique passcode, which is generated and encrypted by the YubiKey. Steps to Reproduce (for bugs) 1: Create a database using Yubikey challenge-response (save the secret used the configure the. 9. OATH. Posts: 9. Use the YubiKey Manager to configure FIDO2, OTP and PIV functionality on your YubiKey on Windows, macOS, and. Credential IDs are linked with another attribute within the response. This includes all YubiKey 4 and 5 series devices, as well as YubiKey NEO and YubiKey NFC. Using. The. Choose “Challenge Response”. Deletes the configuration stored in a slot. "Type" a. The YubiKey is given your password as a Challenge, where it performs some processing using the Challenge and the secret it has, providing the Response back to ATBU. e. Remove YubiKey Challenge-Response; Expected Behavior. You can add up to five YubiKeys to your account. In the SmartCard Pairing macOS prompt, click Pair. KeePass natively supports only the Static Password function. Apps supporting it include e. The U2F application can hold an unlimited number of U2F credentials and is FIDO certified. U2F. Also if I test the yubikey in the configuration app I can see that if I click. . Encrypting a KeePass Database Enable Challenge/Response on the Yubikey. Additionally, KeeChallenge encrypts the S with the pre-calculated challenge-response pair, and stored the encrypted secret and challenge in an auxiliary XML file. An HMAC-SHA1 Challenge-Response credential enables software to send a challenge to the YubiKey and verify that an expected, predetermined response is returned. “Implementing the challenge-response encryption was surprisingly easy by building on the open source tools from Yubico as well as the existing full disk. This means the same device that you use to protect your Microsoft account can be used to protect your password manager, social media accounts, and your logins to hundreds of services. Enpass could be one, but I'm unsure if they support yubikey. 1b) Program your YubiKey for HMAC-SHA1 Challenge Response using the YubiKey Personalization Tool. Initial YubiKey Personalization Tool Screen Note that triggering slot 2 requires you to hold the YubiKey's touch sensor for 2+ seconds; slot 1 is triggered by touching it for just 1-2 seconds. Posts: 9. OK. YubiKey Manager: Challenge-response secret key; Set your HMAC-SHA1 challenge-response parameters: Secret key — press Generate to randomize this field. If a shorter challenge is used, the buffer is zero padded. In this example we’ll use the YubiKey Personalization Tool on Mac, but the steps will be very similar on other platforms. It will be concatenated with the challenge and used as your LUKS encrypted volume passphrase for a total length of 104 (64+40) bytes. This option is only valid for the 2. so, pam_deny. This creates a file in ~/. YubiKey Personalization Tool shows whether your YubiKey supports challenge-response in the lower right. Also, I recommend you use yubkiey's challenge-response feature along with KeepassXC. . auth required pam_yubico. A YubiKey has two slots (Short Touch and Long Touch). This permits OnlyKey and Yubikey to be used interchangeably for challenge-response with supported applications. Additionally, KeeChallenge encrypts the S with the pre-calculated challenge-response pair, and stored the encrypted secret and challenge in the XML file. There are a number of YubiKey functions. install software for the YubiKey, configure the YubiKey for the Challenge-Response mode, store the password for YubiKey Login and the Challenge-Response secret in dom0, enable YubiKey authentication for every service you want to use it for. OATH. Currently I am using KeypassXC with yubikey challenge-response in a ten user environment. To allow the YubiKey to be compatible across multiple hardware platforms and operating systems, the YubiKey appears as a USB keyboard to the operating system. The yubikey_config class should be a feature-wise complete implementation of everything that can be configured on YubiKeys version 1. Re-enter password and select open. From KeePass’ point of view, KeeChallenge is no different. . When I changed the Database Format to KDBX 4. Mutual Auth, Step 1: output is Client Authentication Challenge. Open Yubikey Manager, and select. YubiKey 2. Add a Review Downloads: 0 This Week Last Update: 2016-10-30. Ensure that the challenge is set to fixed 64 byte (the yubikey does some odd formatting games when a variable length is used, so that's unsupported at the moment). OATH. The "challenge-response" function of the OTP applet ("YubiKey slots") uses HMAC to compute the response from the challenge. Next, select Long Touch (Slot 2) -> Configure. Select Challenge-response credential type and click Next. You will then be asked to provide a Secret Key. The U2F application can hold an unlimited number of U2F credentials and is FIDO certified. In order to protect your KeePass database using a YubiKey, follow these steps: Start a text editor (like Notepad). A Yubikey, get one from: Yubico; A free slot on the Yubikey to be configured for. It does so by using the challenge-response mode. Add a "Recovery" box to the challenge-response area that allows a hex string to be entered and used for the challenge response computation. 4. Send a challenge to a YubiKey, and read the response. YubiKey challenge-response USB and NFC driver. If you've already got that and the configure button still reports "challenge-response failed" I'd like to know more about the flags set on your YubiKey. Apparently Yubico-OTP mode doesn’t work with yubico-pam at the moment. If you ever lose your YubiKey, you will need that secret to access your database and to program the. In practice, two-factor authentication (2FA). Be able to unlock the database with mobile application. U2F. The YubiKey Personalization Tool can help you determine whether something is loaded. conf to make following changes: Change user and group to “root” to provide the root privileges to radiusd daemon so that it can call and use pam modules for authentication. Edit the radiusd configuration file /etc/raddb/radiusd. Trochę kombinowałem z ustawieniami w Yubico Manager. Challenge-response does not return a different response with a single challenge. Configures the challenge-response to use the HMAC-SHA1 algorithm. the Challenge-Response feature turns out to be a totally different feature than what accounts online uses. After that you can select the yubikey. Having a backup YubiKey is one thing (and mandatory IMHO), but having another way in is prudent. YubiKey SDKs. Set to Password + Challenge-Response. Yubikey challenge-response already selected as option. Challenge-Response Mode General Information A YubiKey is basically a USB stick with a button. The problem with Keepass is anyone who can execute Keepass can probably open up the executable with notepad, flip a bit in the code, and have the challenge-response do the. . The first 12 characters of a Yubico OTP string represent the public ID of the YubiKey that generated the OTP--this ID remains constant across all OTPs generated by that individual key. Reason: Topic automatically closed 6 months after creation. If valid, the Yubico PAM module extracts the OTP string and sends it to the Yubico authentication server or else it. Or will I need a second slot to have Yubico OTP /and/ Challenge Response (ykchalresp) ?? A slot has either a Yubico OTP or a challenge-response credential configured. HMAC-SHA1 Challenge-Response; Static Password; OATH-HOTP; USB Interface: OTP. 1. Now on Android, I use Keepass2Android. Defaults to client. Ensure that the challenge is set to fixed 64 byte (the yubikey does some odd formatting games when a variable length is used, so that's unsupported at the moment). KeePass is a light-weight and easy-to-use open source password manager compatible with Windows, Linux, Mac OS X, and mobile devices with USB ports. The YubiHSM secures the hardware supply chain by ensuring product part integrity. Challenge-response. (Edit: also tested with newest version April 2022) Note While the original KeePass and KeePassXC use the same database format, they implement the challenge-response mode differently. KeeChallenge has not been updated since 2016 and we are not sure about what kind of support is offered. Please add funcionality for KeePassXC databases and Challenge Response. In KeePass' dialog for specifying/changing the master key (displayed when. The YubiKey response is a HMAC-SHA1 40 byte length string created from your provided challenge and 20 byte length secret key stored inside the token. Tried all. Challenge response uses raw USB transactions to work. Agreed you can use yubikey challenge response passively to unlock database with or without a password. This mode is used to store a component of master key on a YubiKey. Two YubiKeys with firmware version 2. The format is username:first_public_id. Choose PAM configuration In order for KeePassXC to properly detect your Yubikey, you must setup one of your two OTP slots to use a Challenge Response. Single-factor (YubiKey only) authentication is not recommended for production use, as a lost or stolen YubiKey. Yubico Login for Windows adds the Challenge-Response capability of the YubiKey as a second factor for authenticating to local Windows accounts. In order to authenticate successfully, the YubiKey has to answer an incoming challenge with the correct response, which it can only produce using the secret. 5 beta 01 and key driver 0. Steps to Reproduce (for bugs) 1: Create a database using Yubikey challenge-response (save the secret used the configure the. Extended Support via SDK. intent. Note. Please be aware that the current limitation is only for the physical connection. To further simplify for Password Safe users, Yubico offers a pre. Mode of operation. HOTP - extremely rare to see this outside of enterprise. That said the Yubikey's work fine on my desktop using the KeepasXC application. so modules in common files). KeeChallenge works using the HMAC-SHA1 challenge response functionality built into the Yubikey. PORTABLE PROTECTION – Extremely durable, waterproof, tamper resistant,Because both physical keys use the same challenge-response secret, they should both work without issue. Interestingly, this costs close to twice as much as the 5 NFC version. Imperative authentication through YubiKey Challenge-Response when making security-related changes to database settings. Tap the metal button or contact on the YubiKey. YubiKey FIPS (4 Series) CMVP historical validation list; Infineon RSA Key Generation Issue - Customer Portal; Using YubiKey PIV with Windows' native SSH client; Ubuntu Linux 20+ Login Guide - Challenge Response; YubiKey 5 Series Technical Manual; YubiKey FIPS (4 Series) Deployment Considerations; YubiKey 5 Series Quick Start GuideOATH-HOTP. Note that 1FA, when using this feature, will weaken security as it no longer prompts for the chalenge password and will decrypt the volume with only the Yubikey being present at boot time. If you have already setup your Yubikeys for challenge. This creates a file. Time based OTPs- extremely popular form of 2fa. This procedure is supported by KeePassXC, Keepass4Android and Strongbox. I don't know why I have no problems with it, I just activated 2fa in KeepassXC and was able to unlock my DB on my phone with "Password + Challenge. Problem z uwierzytelnieniem Yubikey 5 poprzez moduł NFC - Android 12. I tried configuring the YubiKey for OTP challenge-response, same problem. Login to Bitwarden mobile app, enter your master password and you will get a prompt for WebAuthn 2FA verification. Insert the YubiKey and press its button. You can access these setting in KeepassXC after checking the Advanced Settings box in the bottom left. All three modes need to be checked: And now apps are available. 8 YubiKey Nano 14 3 Installing the YubiKey 15 3. Challenge ResponseかFIDO U2Fかです。Challenge Responseの方を試してないので推測ですが、Challenge Responseはユーザの操作不要、FIDO U2FはYubiKeyに触れるプロセスが必要っぽいです。 それぞれでインストールするモジュールが異なります。私は今回FIDO U2Fを選択します. Initial YubiKey Personalization Tool ScreenNote that triggering slot 2 requires you to hold the YubiKey's touch sensor for 2+ seconds; slot 1 is triggered by touching it for just 1-2 seconds. Test your backup ways in, all of them, before committing important data to your vault, and always remember to keep a separate backup (which itself can be encrypted with just a complex password). websites and apps) you want to protect with your YubiKey. This key is stored in the YubiKey and is used for generating responses. ykDroid will. J-Jamet moved this from In progress to To do in 3. Challenge-response isn't much stronger than using a key-file on a USB stick, or using a static password with a YubiKey (possibly added to a password you remember). I don't see any technical reason why U2F or challenge-response mode would not be suitable for the Enpass. Last edited by LockBot on Wed Dec 28, 2022 12:16 pm, edited 1 time in total. Click Save. Type password. Note: If this prompt doesn't appear, see the Troubleshooting and Additional Topics section below. 3 (USB-A). Good for adding entropy to a master password like with password managers such as keepassxc. HOTP - extremely rare to see this outside of enterprise. and can be used for challenge-response authentication. serial-btn-visible: The YubiKey will emit its serial number if the button is pressed during power-up. 3: Install ykman (part of yubikey-manager) $ sudo apt-get install yubikey-manager. Download. Une fois validé, il faudra entrer une clef secrète. See examples/nist_challenge_response for an example. Challenge-Response Timeout controls the period of time (in seconds) after which the OTP module Challenge-Response should timeout. Configure a static password. Plug in the primary YubiKey. If valid, the Yubico PAM module extracts the OTP string and sends it to the Yubico authentication server or else it. An additional binary (ykchalresp) to perform challenge-response was added. I tried each tutorial for Arch and other distros, nothing worked. When the secret key is implanted, the challenge response is duplicated to each yubikey I implant it onto. xx) KeeChallenge, the KeePass plugin that adds support for Challenge-Response; Setup. KeeWeb connects to YubiKeys using their proprietary HMAC-SHA1 Challenge-Response API, which is less than ideal. Use "client" for online validation with a YubiKey validation service such as the YubiCloud, or use "challenge-response" for offline validation using YubiKeys with HMAC-SHA-1. The first command (ykman) can be skipped if you already have a challenge-response credential stored in slot 2 on your YubiKey. This makes challenge questions individually less secure than strong passwords, which can be completely free-form. Actual BehaviorNo option to input challenge-response secret. Thanks for the input, with that I've searched for other solutions to passtrough the whole USB device and its working: The trick is to activate RemoteFX and to add the GUIDs from the Yubikey to the client registry. The described method also works without a user password, although this is not preferred. 2 Revision: e9b9582 Distribution: Snap. exe "C:My DocumentsMyDatabaseWithTwo. Then “HMAC-SHA1”. When you unlock the database: KeeChallenge loads the challenge C from the XML file and sends it to the YubiKey. For optimal user experience, we recommend to not have “button press” configured for challenge-response. If you're using the yubikey with NFC you will also need to download an app called "ykDroid" from the playstore- this is a passive application that acts as a driver. I've got a KeePassXC database stored in Dropbox. select challenge response. 0. I've tried windows, firefox, edge. The YubiKey firmware does not have this translation capability, and the SDK does not include the functionality to configure the key with both the HID and UTF representations of a static password during configuration. The challenge is stored to be issued on the next login and the response is used as an AES256 key to encrypt the secret. Check Key file / provider: and select Yubikey challenge-response from drop-down. Hi, I use Challenge-Response on one of the two slots of my Yubikey (5 I think) for unlocking KeePassXC and it works out of the box with KeePass2Android, with a pretty high number of iterations. (Verify with 'ykman otp info') Repeat both or only the last step if you have a backup key (strongly recommended). In addition to FIDO2, the YubiKey 5 series supports: FIDO U2F, PIV (smart card), OpenPGP, Yubico OTP, OATH-TOTP, OATH-HOTP, and challenge-response. In this example we’ll use the YubiKey Personalization Tool on Mac, but the steps will be very similar on other platforms. I searched the whole Internet, but there is nothing at all for Manjaro. This is a similar but different issue like 9339. Manage certificates and PINs for the PIV application; Swap the credentials between two configured. Re-enter password and select open. Configuring the OTP application. I added my Yubikeys challenge-response via KeepassXC. Two major differences between the Yubico OTP and HMAC-SHA1 challenge-response credentials are: The key size for Yubico OTP is 16 bytes, and the key size for HMAC. In this howto I will show, how you can use the yubikey to protect your encrypted harddisk and thus addind two factor authentication to your pre. When you unlock the database: KeeChallenge loads the challenge C from the XML file and sends it to the. Mode of operation. Quite for a while the yubikey supports a challenge response mode, where the computer can send a challenge to the yubikey and the yubikey will answer with a response, that is calculated using HMAC-SHA1. /klas. PORTABLE PROTECTION – Extremely durable, waterproof, tamper resistant,A YubiKey have two slots (Short Touch and Long Touch), which may both be configured for different functionality. Remove YubiKey Challenge-Response; Expected Behavior. Same problem here with a macbook pro (core i7) and yubikey nano used in challenge response mode both for login and screen unlock. 2 Audience Programmers and systems integrators. Strong security frees organizations up to become more innovative. Features. Commands. If you install another version of the YubiKey Manager, the setup and usage might differ. It will allow us to generate a Challenge response code to put in Keepass 2. So you definitely want have that secret stored somewhere safe if. 03 release (and prior) this method will change the LUKS authentication key on each boot that passes. KeePassXC offers SSH agent support, a similar feature is also available for KeePass using the KeeAgent plugin. The OS can do things to make an attacker to not manipulate the verification. In HMAC-SHA1, a string acts as a challenge and hashes the string with a stored secret, whereas Yubico OTP. Start with having your YubiKey (s) handy. My device is /dev/sdb2, be sure to update the device to whichever is the. Debug info: KeePassXC - Version 2. KeePass itself supports YubiKey in static mode (YK simulates a keyboard and types your master password), as well as HOTP and challenge-response modes (with the OtpKeyProv and KeeChallenge plugin, respectively). If you are on Windows 10 Pro or Enterprise, you can modify the system to allow companion devices for Windows Hello. Must be managed by Duo administrators as hardware tokens. Categories. Deletes the configuration stored in a slot. 1. Is it possible to use the same challenge response that I use for the pam authentication also for the luks one . Open Terminal. so and pam_permit. Private key material may not leave the confines of the yubikey. 5. Yubico OTPs can be used for user authentication in single-factor and two-factor authentication scenarios. Hello, is there a switch for "Yubikey challenge-response" as Key-File (like -useraccount switch) to open a file with command line? This doesn't work: KeePass. Posted: Fri Sep 08, 2017 8:45 pm. Bitwarden Pricing Chart. KeeChallenge 1. This does not work with. Setup. It is better designed security-wise, does not need any additional files, and is supported by all the apps that support YubiKey challenge-response: KeePassXC, KeeWeb, KeePassium, Strongbox, Keepass2Android, KeePassDX, and probably more. SmartCardInterface - Provides low level access to the Yubikey with which you can send custom APDUs to the key. ykpass . As the legitimate server is issuing the challenge, if a rogue site or middle-man manipulates the flow, the server will detect an abnormality in the response and deny the transaction. 2. Used KeePassXC to Change Master Key and configure YubiKey Challenge-Response. I configured the YubiKey to emit a static password like "test123" and verified that it will output this to Notepad. I used KeePassXC to set-up the challenge response function with my YubiKey along with a strong Master Key. Note: This section can be skipped if you already have a challenge-response credential stored in slot 2 on your YubiKey. so mode=challenge-response Once your YubiKey (or OnlyKey, you got the point…) is set up, open your database in KeePassXC, go to File / Change master key, enable Challenge Response and then save the database. How do I use the Touch-Triggered OTPs on a Mobile Device? When using the YubiKey as a Touch-Triggered One-Time Password (OTP) device on a mobile platform, the user experience is slightly different. g. 4. In the 19. The YubiKey 5Ci is like the 5 NFC, but for Apple fanboys. The YubiKey will then create a 16. Ensure that the challenge is set to fixed 64 byte (the Yubikey does some odd formatting games when a variable length is used, so that's unsupported at the moment). 3 to 3. As the legitimate server is issuing the challenge, if a rogue site or middle-man manipulates the flow, the server will detect an abnormality in the response and deny the. Expand user menu Open settings menu Open settings menuWhat is YubiKey challenge response? The YubiKey supports two methods for Challenge-Response: HMAC-SHA1 and Yubico OTP. Select HMAC-SHA1 mode. Note. The "3-2-1" backup strategy is a wise one. Overview This pull request adds support for YubiKey, a USB authentication device commonly used for 2FA. Any key may be used as part of the password (including uppercase letters or other modified characters). The levels of protection are generally as follows:YubiKey challenge-response for node. Yubico Login for Windows is a full implementation of a Windows Authentication Package and a Credential Provider. Context. Update: Feel like a bit of a dope for not checking earlier, but if you go to the KeePassXC menu, then click About KeePassXC, at the bottom of the resulting window it lists "Extensions". 5 Challenge-response mode 11 2. Instead they open the file browser dialogue. It should start with "cc" or "vv". HMAC-SHA1 Challenge-Response. This does not work with. SoCleanSoFresh • 4 yr. auth required pam_yubico.