ssh no longer supports rsa by default

Today, after upgrading Manjaro, the most basic ssh login suddenly had issues, and the prompts were as follows:

Unable to negotiate with UNKNOWN port 65535: no matching host key type found. Their offer: ssh-rsa,ssh-dss
lost connection

sign_and_send_pubkey: no mutual signature supported

Upon investigation, I found out…well, OpenSSH deems the ssh-rsa encryption method insecure and has directly disabled this key type for logins by default starting from 8.8…

I initially thought that Manjaro lags behind Arch by several versions, so I went to the Archwiki for a solution, but it wasn’t mentioned yet… After searching for half an hour, I founded that I could add the following lines in ~/.ssh/config to resolve the issue:

1
2
3

Host *
    PubkeyAcceptedKeyTypes +ssh-rsa
    HostKeyAlgorithms +ssh-rsa

The first line means it applies to all hosts, the second line adds ssh-rsa back into the allowed use range, and the third line specifies that all hosts should use the ssh-rsa algorithm’s key.
Through actual testing, both lines are required; without the second line, it prompts that there is no ssh-rsa type, and without the third line, it prompts sign_and_send_pubkey: no mutual signature supported.

That’s all~