SSH Connector issue


I’m trying to connect to a SFTP site but it gives me following error;

DH key size must be multiple of 64, and can only range from 512 to 8192 (inclusive). The specific key size 2070 is not supported (InvalidAlgorithmParameterException)

I couldn’t find a way to solve this issue. I hope someone can help me.

I’m using KNIME 4.4 by the way.

Thanks in advance.


Hello @ngonenc,

was connection working properly with 4.3.x?


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No, I tried that with 4.3.3 as well and received the same error.
I used Python to solve the issue for now.

It seems the error comes from the Java but I couldn’t find a way to solve it.


Hi @ngonenc , 2070 is an odd number (as in weird), do you know where in the build is the DH key size 2070 defined? The size is within the range of 512 to 8192. It’s just that it has to be a multiple of 64.

I don’t think that this is something that Knime introduced, there must be a jar file with custom build that is defining the DH Key size at 2070.

I don’t have any issue using the ssh connector node:

Can you try to connect via SSH to your site using something like PuTTY to see if you get the same error (that is if PuTTY would use the same jar file)?

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Sorry I couldn’t answer sooner.

I tried this in different machines, one with 4.3 installed and the other with 4.4. I received the same error in both cases. I can connect to the site using WinSCP without an issue.

And then I found a Python script which has some security policies (hellman-group) that helped the flow to connect to sftp and download the zip file.

I don’t know where to adjust the DH key size, so my solution is to use Python.


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