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Hello,

I am an Android 12 user and running AndFTP which is a great tool to connect to (almost) any Linux Box. I love it ! However, I ran into a problem with it...

I have a trouble running AndFTP v6.3 on Android 12 connecting to my Linux Server at Home.

I've recently upgraded my Linux Server to Ubuntu 22.04.1 (OpenSSH_8.9p1 Ubuntu-3, OpenSSL 3.0.2) and AndFTP does not connect anymore using the PubKey method.

auth.log on the server throws the following: My SSH Key is OK (it spits out a SHA256 fingerprint), also I use this key with JuiceSSH (on Android 12) and I use this key on my laptop so the Key is OK.
All of the above use another more sophisticated mechanism, not just plain "ssh-rsa".
The only one that seems to have a trouble authenticating is AndFTP.

From what I understand, OpenSSH has put some security restrictions in place in order not to allow weak algorithms to be used.

I assume AndFTP needs a key upgrade procedure or something like that...

If anyone can help, please... otherwise, I must change AndFTP to other SFTP Client.

Hi,

In your AndFTP configuration, Advanced tab => Expert settings, there is a SSH provider option, could you try all (one by one, don't forget to click save each time) with your key?

I just ran into this same issue trying to connect from an Android 13 phone to an Ubuntu 22.04.2 server running OpenSSH 8.9p1.

The solution was indeed to switch the SSH Provider in the AndFTP connection advanced settings from Default to Secure (includes ED25519).

Hi!

Similar issue here. Newer server with newer ssh version, sshd logs

no matching host key type found. Their offer: ssh-rsa,ssh-dss [preauth]

Neither option for the SSH provider option helps. Enabeling now legacy options in the sshd config makes the connection work, but this is not a good solution. See eg

https://www.gentoo.org/support/news-ite ... -sha1.html

Can we expect an AndFTP that supports newer, safer, non-sha1 based, key negotiations for sftp?

Please upgrade to AndFTP 6.7