2.0.8.1 update may request SSH/SFTP ssh-ed25519 host key reverification

[hellcake]

@ts678

I’m not sure what’s going on, but I’ll ask @hellcake if the server is some familiar type, e.g. OpenSSH?
Did the fingerprint work with 2.0.7.1 just before 2.0.8.1, and were there any ssh server changes done?

The server is OpenSSH (preinstalled by a vds provider, but I’m certain nothing unusual about it). It was working before the update. No changes were made on the server side.

@ts678

I think I found where the ed25519 key length gets converted from bytes to bits via a bug fix awhile back:

SSH.NET/src/Renci.SshNet/Security/Cryptography/ED25519Key.cs at 1de33c469e893d81e27ed7076e2a6ba94ff4963d · sshnet/SSH.NET · GitHub

This probably explains one 32 becoming 256

Looks like the case of 32 -256 change. It was the key length and before the update it was in bytes.

@kenkendk

You can see the number after ssh-ed25519 is changed from 32 to 256, so what I understand from the error message is that you are seeing the same server key, but now using the 256 bit key instead of the previous 32 bit key.

All Ed25519 are 256 bit. Likely 32 was the key length in bytes as @ts678 found out above