.ssh
|-- authorized_keys
|-- conf.d
|   |-- hetzner.conf
|   |-- hollandpark.conf
|   |-- nsas.conf
|   |-- other.conf
|   `-- swissbit.conf
|-- config
|-- id_ecdsa_sk -> keys/old/id_ecdsa_sk
|-- id_ecdsa_sk-NSAS -> keys/old/id_ecdsa_sk-NSAS
|-- id_ecdsa_sk-NSAS.pub -> keys/old/id_ecdsa_sk-NSAS.pub
|-- id_ecdsa_sk-swissbit -> keys/old/id_ecdsa_sk-swissbit
|-- id_ecdsa_sk-swissbit.pub -> keys/old/id_ecdsa_sk-swissbit.pub
|-- id_ecdsa_sk.pub -> keys/old/id_ecdsa_sk.pub
|-- id_ed25519 -> keys/michel/id_ed25519-Michel-automation
|-- id_ed25519.pub -> keys/michel/id_ed25519-Michel-automation.pub
|-- id_ed25519_nsas -> keys/old/id_ed25519_nsas
|-- id_ed25519_nsas.pub -> keys/old/id_ed25519_nsas.pub
|-- id_ed25519_sk -> keys/michel/id_ed25519_sk_rk_YKc-Michel
|-- id_ed25519_sk.pub -> keys/michel/id_ed25519_sk_rk_YKc-Michel.pub
|-- id_rsa -> keys/michel/id_rsa_Michel-fallback
|-- id_rsa.pub -> keys/michel/id_rsa_Michel-fallback.pub
|-- keys
|   |-- hollandpark
|   |   |-- id_ed25519
|   |   |-- id_ed25519.pub
|   |   |-- id_ed25519_sk-YKc-Automation-Hollandpark
|   |   `-- id_ed25519_sk-YKc-Automation-Hollandpark.pub
|   |-- josephs
|   |   |-- id_ed25519_sk-YKc-Automation-Josepfs
|   |   `-- id_ed25519_sk-YKc-Automation-Josepfs.pub
|   |-- michel
|   |   |-- id_ecdsa_sk-ndc_YKa-Michel
|   |   |-- id_ecdsa_sk-ndc_YKa-Michel.pub
|   |   |-- id_ed25519-Michel-automation
|   |   |-- id_ed25519-Michel-automation.pub
|   |   |-- id_ed25519_sk-ndc_YKc-Michel
|   |   |-- id_ed25519_sk-ndc_YKc-Michel.pub
|   |   |-- id_ed25519_sk-rk_YKc-Michel-automation
|   |   |-- id_ed25519_sk-rk_YKc-Michel-automation.pub
|   |   |-- id_ed25519_sk_rk_YKc-Michel
|   |   |-- id_ed25519_sk_rk_YKc-Michel.pub
|   |   |-- id_rsa_Michel-fallback
|   |   `-- id_rsa_Michel-fallback.pub
|   |-- nsas
|   |   |-- id_ecdsa_sk-NSAS
|   |   |-- id_ecdsa_sk-NSAS.pub
|   |   |-- id_ed25519_sk_rk_YKc_NSAS
|   |   `-- id_ed25519_sk_rk_YKc_NSAS.pub
|   |-- old
|   |   |-- id_ecdsa_sk
|   |   |-- id_ecdsa_sk-NSAS
|   |   |-- id_ecdsa_sk-NSAS.pub
|   |   |-- id_ecdsa_sk-swissbit
|   |   |-- id_ecdsa_sk-swissbit.pub
|   |   |-- id_ecdsa_sk.pub
|   |   |-- id_ed25519
|   |   |-- id_ed25519.pub
|   |   |-- id_ed25519_nsas
|   |   `-- id_ed25519_nsas.pub
|   |-- schraubenscholz
|   |   |-- id_ed25519_sk-YKc-Automation-Scholz
|   |   `-- id_ed25519_sk-YKc-Automation-Scholz.pub
|   |-- swissbit
|   |   |-- id_ecdsa_sk-swissbit
|   |   `-- id_ecdsa_sk-swissbit.pub
|   `-- xecuro
|       |-- id_ed25519_sk_rk_YKc-xecuro
|       `-- id_ed25519_sk_rk_YKc-xecuro.pub
|-- known_hosts
|-- known_hosts.old
|-- old
|   |-- known_hosts
|   `-- known_hosts.old
|-- scripts
|   `-- sshfpgen
|-- sockets
`-- test

~/.ssh/config

#=======================================================================
# Global
#=======================================================================
include ~/.ssh/conf.d/nsas.conf
include ~/.ssh/conf.d/hetzner.conf
include ~/.ssh/conf.d/hollandpark.conf
include ~/.ssh/conf.d/swissbit.conf
include ~/.ssh/conf.d/other.conf
#=======================================================================
# Global
#=======================================================================
Host *
    LogLevel QUIET
    ControlMaster auto
    ControlPath ~/.ssh/sockets/%r@%h:%p 	# automatically add ssh keys to running ssh agent (mkdir -p ~/.ssh/sockets)
    ControlPersist yes 				# keep connections open indefinitely, even after logging out
    ForwardAgent yes       			# ssh -A host # on the command line
    VerifyHostKeyDNS no				# Specifies whether to verify the remote key using DNS and SSHFP
    AddKeysToAgent yes
    TCPKeepAlive yes
    Compression yes
    StrictHostKeyChecking no
    VersionAddendum none
    UpdateHostKeys yes
    # IdentitiesOnly yes
    PreferredAuthentications publickey,password
    # HostKeyAlgorithms +ssh-rsa
    # PubkeyAcceptedKeyTypes +ssh-rsa
    # Ensure KnownHosts are unreadable if leaked - it is otherwise easier to know which hosts your keys have access to.
    HashKnownHosts yes
    # Host keys the client accepts - order here is honored by OpenSSH
    HostKeyAlgorithms ssh-ed25519-cert-v01@openssh.com,ssh-rsa-cert-v01@openssh.com,ssh-ed25519,ssh-rsa,ecdsa-sha2-nistp521-cert-v01@openssh.com,ecdsa-sha2-nistp384-cert-v01@openssh.com,ecdsa-sha2-nistp256-cert-v01@openssh.com,ecdsa-sha2-nistp521,ecdsa-sha2-nistp384,ecdsa-sha2-nistp256
    KexAlgorithms curve25519-sha256@libssh.org,ecdh-sha2-nistp521,ecdh-sha2-nistp384,ecdh-sha2-nistp256,diffie-hellman-group-exchange-sha256
    MACs hmac-sha2-512-etm@openssh.com,hmac-sha2-256-etm@openssh.com,umac-128-etm@openssh.com,hmac-sha2-512,hmac-sha2-256,umac-128@openssh.com
    Ciphers chacha20-poly1305@openssh.com,aes256-gcm@openssh.com,aes128-gcm@openssh.com,aes256-ctr,aes192-ctr,aes128-ctr

Recomendation:

ssh-keygen -t ed25519-sk -O application=ssh:YKc-Michel-ndc -O verify-required -O user=michel

This will generate a non discoverable key that used for signing the generated (ided25519sk) So in order to login to an other system, the private key (ided25519sk) and the non discoverable key (on Yubikey) is needed, beside the Yubikey pin and the passphrase.

ssh-keygen -t ed25519-sk -O resident -O application=ssh:YKc-Michel -O verify-required -O user=michel

This key can be downloaded from the Yubikey.

ssh-keygen -t ed25519-sk -O resident -O application=ssh:YKc-Automation-Michel -O user=michel -O no-touch-required -C "Michel Pelzer (Automation)- mp@nsas.de"

This key requires the presens of the Yubikey, but does not need to be touched. (authorizedkeys) need the no-touch-required in front of the public key. <file plain ~/.ssh/authorizedkeys></file>

~/.ssh/authorized_keys

# Michel
no-touch-required sk-ssh-ed25519@openssh.com AAAAGnNrLXNzaC1lZDI1NTE5QG9wZW5zc2guY29tAAAAIEawzv7L8w9eetH03oc8XHuc02gX/MCmr3sUDHH8opKVAAAAGXNzaDpZS2MtQXV0b21hdGlvbi1NaWNoZWw= Michel Pelzer (Automation)- mp@nsas.de
sk-ssh-ed25519@openssh.com AAAAGnNrLXNzaC1lZDI1NTE5QG9wZW5zc2guY29tAAAAIEvFa/NonVUOvoRRsx151bAJxjgckXC3sLqUb/kdQP9TAAAADnNzaDpZS2MtTWljaGVs Michel Pelzer - mp@nsas.de
sk-ssh-ed25519@openssh.com AAAAGnNrLXNzaC1lZDI1NTE5QG9wZW5zc2guY29tAAAAIJ2Za0UMRtm+LwEGEmug1QNoBEoV/0xDmCRpAXqsqNfXAAAADnNzaDpZS2MtTWljaGVs Michel Pelzer - mp@nsas.de
# NSAS
sk-ssh-ed25519@openssh.com AAAAGnNrLXNzaC1lZDI1NTE5QG9wZW5zc2guY29tAAAAIDp7SK9FxZJUQW+jz2ciChN7SwT6SdmovhLUlBLzhIkRAAAADHNzaDpZS2MtTlNBUw== NSAS - Network System Access Solutions
sk-ecdsa-sha2-nistp256@openssh.com AAAAInNrLWVjZHNhLXNoYTItbmlzdHAyNTZAb3BlbnNzaC5jb20AAAAIbmlzdHAyNTYAAABBBPneb67QG6/Z2BdcCBvZgiXVejD4ZGAAxgEoCx2aSbbegqSj1rSW9m2jkdRnwrQix//JfblvLOG/pXXQZJzPkHcAAAAEc3NoOg== NSAS-U2F

ykman fido credentials list

ykman fido credentials delete ssh:YKc-Automation-Michel

ssh-keygen -K

List

ykman --reader yubico oath accounts

Add

ykman --reader yubico oath accounts add "NAME"