Update Securing_SSH_with_FIDO2.adoc

update troubleshooting

content/SSH/Securing_SSH_with_FIDO2.adoc

@@ -226,23 +226,19 @@ ssh -vvv user@host
 chmod 600 ~/.ssh/id_ed25519_sk
 ----
 
-*Verify the FIDO2 credential on security key*
+*Unsure which security key holds the credential*
+
+Regenerate key files from the security key and compare public keys.
 
 . Open a terminal and use:
 +
 [source,sh]
 ----
-ykman fido credentials list
+ssh-keygen -K
 ----
 +
-. Enter the PIN.
-. Verify Credential ID
-+
-[source,sh]
-----
-Credential ID   RP ID   Username    Display name
-7b68340b....    ssh:    openssh     openssh 
-----
+. Enter the PIN and touch the key when prompted.
+. Compare the newly generated public key to the public key in question
 
 
 == Further Reading