I've been using an ssh key for a long time. Back in the days when RSA keys were mostly commercial/proprietary and when DSA keys where the recommended method.
When ubuntu 16.04 came out, I suddenly couldn't use my key anymore as ubuntu (or perhaps rather its updated ssh server) didn't accept DSA keys anymore. They're apparently not save enough anymore.
I worked around it by adding a setting on the server, telling it to accept my DSA key.
When the latest Apple OS update (Sierra) came out, I suddenly couldn't log in anywhere. Also git pull to github (I'm using ssh) stopped working. I found the cause by passing -vvvv to ssh:
debug1: Next authentication method: publickey debug1: Trying private key: /Users/reinout/.ssh/id_rsa debug3: no such identity: /Users/reinout/.ssh/id_rsa: No such file or directory debug1: Trying private key: /Users/reinout/.ssh/id_ecdsa debug3: no such identity: /Users/reinout/.ssh/id_ecdsa: No such file or directory debug1: Trying private key: /Users/reinout/.ssh/id_ed25519 debug3: no such identity: /Users/reinout/.ssh/id_ed25519: No such file or directory debug2: we did not send a packet, disable method debug3: authmethod_lookup password debug3: remaining preferred: ,password debug3: authmethod_is_enabled password debug1: Next authentication method: password
Oh.... Sierra's ssh client also doens't like DSA anymore. Ok... time to create a new key :-)
... which I did about 6 weeks ago. With a nice, long passphrase. And 2 weeks ago I had to create a new one as I couldn't for the life of me remember the exact passphrase. I've rarely felt so stupid :-) A passprase can have many almost-right variants:
I'll take the train to django under the hood I'll take the train to django under the hood. I'll take the train to Django under the Hood I'll take the train to Django under the Hood. I will take the train to django under the hood I will take the train to django under the hood. I will take the train to Django under the Hood I will take the train to Django under the Hood. I'm taking the train to Django under the Hood. I'm taking the train to Django under the Hood I'm taking the train to Django Under The Hood. I'll go by train to Django Under The Hood. etc... etc...
Well, everything works again :-)