When I set Ciphers in ~/.ssh/config or /etc/ssh/ssh_config to something like this: Ciphers chacha20-poly1305@openssh.com,aes256-gcm@openssh.com,aes128-gcm@openssh.com,aes256-ctr,aes192-ctr,aes128-ctr Dolphin fails with: crypt_set_algorithms2: no crypto algorithm function found for chacha20-poly1305@openssh.com then as I remove algorithms from the beginning, it fails like so: crypt_set_algorithms2: no crypto algorithm function found for aes256-gcm@openssh.com crypt_set_algorithms2: no crypto algorithm function found for aes128-gcm@openssh.com Until it succeeds when no @openssh.com ciphers are at the beginning of the list, it works if they are second or later too, which seems to point to KIO picking the first out of the list and using it instead of picking the first that it can use, which is correct behavior. I found an email from earlier this year about the same problem: https://lists.fedoraproject.org/pipermail/kde/2015-January/014171.html Also now that I'm done typing this up, the system mentions this as a possible duplicate: https://bugs.kde.org/show_bug.cgi?id=226033 It's not, but it could mean this bug is in libssh instead of KIO, but I don't know? If someone can point me in the direction of the relevant code I may be able to come up with a patch.
I have this issue as well when using Dolphin and KIO to connect to remote machines.
Please open a bug upstream https://red.libssh.org/ You should post your config file ...
I had the same problem but could resolve it by updating libssh to version 0.7.1 (from 0.6.5).
I'm still having this issue as well. openSUSE Tumbleweed 20180307 Qt 5.10.0 Plasma 5.12.2 Frameworks 5.43.0 Dolphin 17.12.2 libssh 0.7.5-4.2
Fixed with libssh 0.8 https://www.libssh.org/2018/09/21/libssh-0-8-3/