# Ssh-keygen -t rsa in Rocky 8.5 vs Rocky 8.10 **URL:** \ **Category:** Rocky Linux Help & Support\ **Tags:** rocky-linux-8\ **Created:** [July 25, 2025, 1:17pm UTC](https://forums.rockylinux.org/t/ssh-keygen-t-rsa-in-rocky-8-5-vs-rocky-8-10/19215 "2025-07-25T13:17:24Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![PREngineer](https://avatars.discourse-cdn.com/v4/letter/p/a587f6/32.png) [@PREngineer](https://forums.rockylinux.org/u/PREngineer)\ **Post date:** [July 25, 2025, 1:17pm UTC](https://forums.rockylinux.org/t/ssh-keygen-t-rsa-in-rocky-8-5-vs-rocky-8-10/19215/1 "2025-07-25T13:17:24Z")
I am using Java jsch 0.2.26 for SSH communications between different users within the Rocky 8.5 system. Before I used jsch 0.1.56 on the same platform. To allow for Java to have passwordless SSH I had to run “ssk-keygen -m PEM -t rsa -b 2048”. I learnt that simply running “ssh-keygen -t rsa” in Rocky 8.5 will yield a 3072-bit key by default. My legacy key was not supported by default. Anyway, I upgraded from 0.1.56 to 0.2.26. Then I could remove the old 2048-bit key and install the 3072-bit key. I then installed Rocky 8.10. After running “ssh-keygen -t rsa” on this new OS, I now get an issue of “invalid private key”. To fix this, I had to change and use “ssh-keygen -m PEM -t rsa”. Then the PEM format was accepted. Is there a new change in Rocky 8.10 OpenSSH that requires the change in format? Will it cause any issues when upgrading from 8.5 to 8.10 in the near future? ---
**Author:** ![jlehtone](https://avatars.discourse-cdn.com/v4/letter/j/e9a140/32.png) [@jlehtone](https://forums.rockylinux.org/u/jlehtone)\ **Post date:** [July 25, 2025, 2:07pm UTC](https://forums.rockylinux.org/t/ssh-keygen-t-rsa-in-rocky-8-5-vs-rocky-8-10/19215/2 "2025-07-25T14:07:48Z")
You can: - Check at the version of package `openssh` in 8.5 and then look at `rpm -q --changelog openssh` in 8.10. The log entries since 8.5 (or the ones that cannot be found from the 8.5’s log) could hint something - Browse through RHEL Release notes for versions 8.6–8.10 (in [Red Hat Enterprise Linux | 8 | Red Hat Documentation](https://docs.redhat.com/en/documentation/red_hat_enterprise_linux/8/) ) ---
**Author:** ![iwalker](https://sea2.discourse-cdn.com/flex020/user_avatar/forums.rockylinux.org/iwalker/32/2599_2.png) [@iwalker](https://forums.rockylinux.org/u/iwalker)\ **Post date:** [July 25, 2025, 2:07pm UTC](https://forums.rockylinux.org/t/ssh-keygen-t-rsa-in-rocky-8-5-vs-rocky-8-10/19215/3 "2025-07-25T14:07:58Z")
Not sure I understand your problem. On Rocky 8.10 I just did: ```auto ssh-keygen -t rsa ``` and it worked fine generating me a 3072 rsa key. Sounds like something strange with your machine configuration. But we would need a lot more detail than what you’ve posted to be able to help. ---
**Author:** ![PREngineer](https://avatars.discourse-cdn.com/v4/letter/p/a587f6/32.png) [@PREngineer](https://forums.rockylinux.org/u/PREngineer)\ **Post date:** [July 27, 2025, 2:28pm UTC](https://forums.rockylinux.org/t/ssh-keygen-t-rsa-in-rocky-8-5-vs-rocky-8-10/19215/4 "2025-07-27T14:28:44Z")
Thank you @jlehtone. I notice that the openssh on 8.10 first install is a newer version with lots of CVE fixes. I guess this introduces the format change. But if I install 8.5 and run the upgrade to 8.10, the openssh version remains the same. I will do the upgrade and then upgrade openssh eventually. ---
**Author:** ![jlehtone](https://avatars.discourse-cdn.com/v4/letter/j/e9a140/32.png) [@jlehtone](https://forums.rockylinux.org/u/jlehtone)\ **Post date:** [July 28, 2025, 8:18am UTC](https://forums.rockylinux.org/t/ssh-keygen-t-rsa-in-rocky-8-5-vs-rocky-8-10/19215/5 "2025-07-28T08:18:14Z")
> [@PREngineer](#): > > if I install 8.5 and run the upgrade to 8.10, the openssh version remains the same. Please run `rpm -q openssh` on three systems: - 8.5 - 8.5 upgraded to latest - 8.10 Do you get the exact same strings, or different? ---
**Author:** ![PREngineer](https://avatars.discourse-cdn.com/v4/letter/p/a587f6/32.png) [@PREngineer](https://forums.rockylinux.org/u/PREngineer)\ **Post date:** [July 28, 2025, 9:59am UTC](https://forums.rockylinux.org/t/ssh-keygen-t-rsa-in-rocky-8-5-vs-rocky-8-10/19215/6 "2025-07-28T09:59:18Z")
For 8.5 and 8.5 upgraded to latest it is the same (openssh 8.0). For 8.10, it is openssh 8.7. So they are different strings. ---
**Author:** ![jlehtone](https://avatars.discourse-cdn.com/v4/letter/j/e9a140/32.png) [@jlehtone](https://forums.rockylinux.org/u/jlehtone)\ **Post date:** [July 28, 2025, 11:08am UTC](https://forums.rockylinux.org/t/ssh-keygen-t-rsa-in-rocky-8-5-vs-rocky-8-10/19215/7 "2025-07-28T11:08:01Z")
> [@PREngineer](#): > > For 8.10, it is openssh 8.7. On Rocky 8’s repo I do see: `openssh-8.0p1-25.el8_10.x86_64.rpm` and that is clearly nothing like “8.7”. The Rocky vault shows that Rocky 8.5 had `openssh-8.0p1-10.el8.x86_64.rpm` Therefore, the expectation is: The 8.5 should show `8.0p1-10.el8` The 8.5 after update: `8.0p1-25.el8_10` (which differs from before update) The 8.10 (with update): `8.0p1-25.el8_10` * * * Rocky 9 has OpenSSH **8.7** p1-45.el9.rocky.0.1 (currently). * * * In other words, your “8.10” is not a real _Rocky 8_, but some chimera of who-knows-what. ---
**Author:** ![PREngineer](https://avatars.discourse-cdn.com/v4/letter/p/a587f6/32.png) [@PREngineer](https://forums.rockylinux.org/u/PREngineer)\ **Post date:** [July 28, 2025, 12:03pm UTC](https://forums.rockylinux.org/t/ssh-keygen-t-rsa-in-rocky-8-5-vs-rocky-8-10/19215/8 "2025-07-28T12:03:22Z")
Oh yes, I now see my mistake. I do not know where I got “8.7” from. Someone also sent me screenshots of the different environments and they show 8.0p1-10 and 8.0p1-24 (without update). I have asked them to do a ‘dnf list updates | grep openssh’ because there should be a 8.0p1-25.el8\_10 update. Everything is now starting to make sense. More importantly, I will be able to read the changelog correctly. ---
**Author:** ![jlehtone](https://avatars.discourse-cdn.com/v4/letter/j/e9a140/32.png) [@jlehtone](https://forums.rockylinux.org/u/jlehtone)\ **Post date:** [July 28, 2025, 12:26pm UTC](https://forums.rockylinux.org/t/ssh-keygen-t-rsa-in-rocky-8-5-vs-rocky-8-10/19215/9 "2025-07-28T12:26:33Z")
> [@PREngineer](#): > > I do not know where I got “8.7” from. If it is an RPM, then: ```auto # dnf list openssh Installed Packages openssh.x86_64 8.0p1-25.el8_10 @baseos Available Packages openssh.x86_64 8.0p1-25.el8_10.alma.1 baseos ``` This output is from an AlmaLinux 8 system. It tells (with the `@baseos`) that the currently installed package is from repo ‘baseos’ of AlmaLinux and that same repo has an update available (that I should install). On another system I see: ```auto modeller.x86_64 9.19-1 @/modeller-9.19-1.x86_64 ``` which tells that I have installed local package file (i.e. not from repo), e.g. ```auto dnf install modeller-9.19-1.x86_64.rpm ``` Also, dnf has history. For the above-mentioned “modeller”: ```auto # yum history list modeller Loaded plugins: changelog, fastestmirror, langpacks, list-data, nvidia, priorities, show-leaves, verify ID | Command line | Date and time | Action(s) | Altered ------------------------------------------------------------------------------- 344 | install /home/jlehtone/D | 2017-09-08 13:34 | Install | 1 EE ``` * * * I have also rather long bash history, so I could check that too: `history | grep install.*modeller` (Alas, the history was not _that_ long. Reality: it got wiped at some point.) ---
**Author:** ![system](https://us1.discourse-cdn.com/flex020/uploads/rockylinux/original/1X/91b7219eec10e30013422e4df76c1d898711a5d5.svg) [@system](https://forums.rockylinux.org/u/system)\ **Post date:** [September 26, 2025, 12:26pm UTC](https://forums.rockylinux.org/t/ssh-keygen-t-rsa-in-rocky-8-5-vs-rocky-8-10/19215/10 "2025-09-26T12:26:54Z")
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