GPG agent suddenly stops working (Yubikey 4)

Joe's Avatar


06 Mar, 2018 03:52 PM


I'm using the Yubikey 4 smart card capability for SSH authentication on macOS 10.13.3. After some time (maybe about 30 min), it suddenly stops working.

This is the output of gpg2 --card-status:

Reader ...........: Yubico Yubikey 4 OTP U2F CCID
Application ID ...: D1234567890...
Version ..........: 2.1
Manufacturer .....: Yubico
Serial number ....: 1234567890
Name of cardholder: Joe
Language prefs ...: de
Sex ..............: male
URL of public key : [not set]
Login data .......: [not set]
Signature PIN ....: forced
Key attributes ...: rsa2048 rsa2048 rsa2048
Max. PIN lengths .: 0 0 0
PIN retry counter : 0 0 0
Signature counter : 0
Signature key ....: [none]
Encryption key....: [none]
Authentication key: [none]
General key info..: [none]

As you can see, all three keys change to [none]. All other Yubikey capabilities, (2FA etc.) are still working.
I have to reconnect the Yubikey to make gpg2 working properly again. What is the reason for that behaviour?

gpg (GnuPG/MacGPG2) 2.2.3
libgcrypt 1.8.1


  1. Support Staff 1 Posted by Steve on 08 Mar, 2018 06:55 PM

    Steve's Avatar

    Hi Joe,

    welcome to the GPGTools support platform. Sorry you are having problems using GPG Suite.

    This question is best asked at the gnupg users mailling list.

    All the best,

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