[lug] Windows/PuTTY and Linux SSH Key Pair Compatibility

[duboulder]

Maybe one of these would help:
https://unix.stackexchange.com/questions/74545/what-difference-between-openssh-key-and-putty-key
https://help.cloudforge.com/hc/en-us/articles/215242303-Converting-PuTTY-private-keys-to-OpenSSH-format
[search was for putty ssh key format vs openssh]

The beginning of the public-key line in authorized_keys for a windows user we have configured looks like:
    ssh-rsa AAAAB3...
The key-part is base-64 encoded.

HTH

‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
On Friday, December 28, 2018 2:21 PM, D. Stimits <stimits at comcast.net> wrote:

> I'm trying to find out what is possible for copying a Windows-generated RSA public key (puttygen) to a Linux server. I do not have physical access, and I have my own key set up since I personally only use Linux to log in, but need to add a login for another user...and that user is using Windows. The trouble is that the public key is not what I expected...it is multi-line, it contains other comment, so on. It looks more like an email PGP key, but ignoring actual body content, this is the format:
>
> ---- BEGIN SSH2 PUBLIC KEY ----
> Comment: "rsa-key-20181228"
> ABC...cut...TEn
> DEF...cut...HHN
> ghi...cut...W2L
> JkL...cut...YYB
> XYZ...cut...srW
> Foo...cut...Bar
> ---- END SSH2 PUBLIC KEY ----
>
> So far as I know, the Linux style ".ssh/authorized_keys" would use a single line, and I am guesing that simply concatenating that content like an OpenSSH style single key might break it. I could have other ssh logins ready before doing this, so it isn't 100% that breaking this would lock me out, but I'd rather hear from someone who has done this before what the correct way is.
>
> Or, if there are comments on whether alternates to PuTTY (e.g., WinSCP) have worked out when a Windows user needs to occasionally copy a file to a Linux server (mostly just PDF files to a document directory). My goal is to have the Windows user with a single ssh key and keyless login.
>
> Thanks!
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