Could not negotiate diffie-hellman-group1-sha1 error (wodSFTP / wodSFTP.NET / wodSFTPdll)

Hi,
I'm running a test in C# & Visual Studio 10, and am attempting to connect to a remote SFTP site.

I'm seeing the following error when executing the Connect() call using WeOnlyDo.Client.SFTP.dll.

Could not negotiate diffie-hellman-group1-sha1.

Any thoughts as to what might be causing this error? I am using 3.4.4 version of WeOnlyDo.Client.SFTP.dll.

Hi Trupti.

I think you just need to update wodSFTP.NET to the latest version since it supports other crypto algorithms which are supported by your server.

Or, you can enable that algorithm on the server side, which was disabled recently for some reason (probably server update).

Kind regards,
Jasmine.

Hi Jasmin,

Thanks for your quick assistance. I will check and update you if that works.

Thanks,
Trupti D

Hi Jasmine,
Due to security reason, we can not enable "diffie-hellman-group1-sha1" algorithm at server side.

Can you please tell me, if 3.4.4 version is supporting to "AES-256 SDCTR" algorithm?

Hi,

it does since 3.4.1, you can find details here:

http://www.weonlydo.com/SFTP.NET/sftp-net-component.asp?rnotes=1

Kind regards,
Jasmine.

Hi Jasmine,
I checked details for Version 3.4.1 and it says that version above will support to aes256-ctr encryption algorithm.
I am looking for AES-256 SDCTR key exchange algorithms.
Can you please let us know the all supported key exchange algorithms for Version 3.4.4?
And how we can set up/change required key exchange algorithms while connecting to SFTP (sample code )?

Hi.

I believe it's the same, as per "The Secure Shell (SSH) Transport Layer Encryption Modes" that can be found here

https://www.ietf.org/rfc/rfc4344.txt

You will find:
This document describes the following new methods:

aes128-ctr RECOMMENDED AES (Rijndael) in SDCTR mode,
with 128-bit key
aes192-ctr RECOMMENDED AES with 192-bit key
aes256-ctr RECOMMENDED AES with 256-bit key

so. it's the same. Please do not ask further questions about old versions of wodSFTP.NET - they are no longer supported. You are free to use them, but we provide support and can help only for latest one.

As for specifying which ciphers are supported, it would not help in your specific case since you can't add them by yourself if they are not implemented in wodSFTP.NET code. Latest versions supports EncryptionList and HMACList properties.

Kind regards,
Jasmine.