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sshdigital-signaturersyncmsys2

agent key RSA SHA256:... returned incorrect signature type

I am doing rsync, and I get the message

agent key RSA SHA256:... returned incorrect signature type

Here it is mentioned that "This message isn't intrinsically fatal, although the remote side may choose to reject your connection if it doesn't support SHA-1 signatures." This is exactly what I see: rsync gives me the expected results (I guess it is irrelevant that rsync is involved). This is an explanation of the reasons behind the warning, but I found no way of fixing it.

I am using Msys2 under Win 10.

Is there any way to fix it?

Note that I have tried the following ssh connections among 3 computers:

   Comp A                         Comp B                    Comp C
Win 10, Msys2   ----------->   Ubuntu 18.04   ----------->   RHEL6
     |             Warning                     No warning      ^
     |                                                         |
     |---------------------------------------------------------|
                             No warning

On the client side I am using pageant.exe ver 0.66 and ssh-pageant 1.4 in Msys2 ("An SSH authentication agent for Cygwin/MSYS that links OpenSSH to PuTTY's Pageant.").

Solution

  • As pointed out by bk2204, there is support for SHA-256/512 RSA signatures starting from pageant 0.71.

    So I updated to putty 0.73 and the warning is gone.