C# Host key does not match configured key fingerprint :: Support Forum

goatmandude20
Joined:: 2021-11-23
Posts:: 2
Location:: Utah

C# Host key does not match configured key fingerprint

2021-11-23 21:25

After reading through the WinSCP .NET docs on SSH keys I need some help. I imported the site from a file and can successfully login via the winscp.exe UI. I verified on the server and protocol information form that I am using the correct fingerprint.
Valid fingerprint (copied directly from WinSCP UI):
ssh-rsa 2048 4d+341...
or
ssh-rsa 2048 7b:e4:e2...

Error Messages:

Host key does not match configured key fingerprint "ssh-rsa 2048 7b:e4:e2..."!
Host key fingerprint is ssh-rsa 2048 KWrXZJFJPrG2J37NoVUvsyu/YGuAfwSNzBDz+qZROqY=

Host key does not match configured key fingerprint "ssh-rsa 2048 4d+341..."!
Host key fingerprint is ssh-rsa 2048 KWrXZJFJPrG2J37NoVUvsyu/YGuAfwSNzBDz+qZROqY=

When I try to use the fingerprint the error message suggest it revokes my key...I used the instructions at this link to clear everything and start over: https://winscp.net/eng/docs/ui_cleanup
I could not find anything in the registry or appdata folders that would be caching the "key fingerprint" in the error message.

Below is the C# code for the session options. All values are passed in from an XML config file and are valid. The only issue is with the fingerprint...

C# Code

SessionOptions sessionOptions = new SessionOptions()
{
    Protocol = Protocol.Sftp,
    HostName = hostName,
    UserName = userName,               
    SshPrivateKeyPath = SshPrivateKeyPath,
    PrivateKeyPassphrase = password,                                
    SshHostKeyFingerprint = sshHostKeyFingerPrint,
    PortNumber = 22
};

How do I overcome this mismatch? Thanks,

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martin◆ Site Admin
Joined:: 2002-12-10
Posts:: 40,567
Location:: Prague, Czechia

Re: C# Host key does not match configured key fingerprint

2021-11-25

See https://winscp.net/eng/docs/faq_hostkey

If it does not help, please post complete session log files both from GUI and code.

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goatmandude20

Re: C# Host key does not match configured key fingerprint

2021-11-30 17:59

Thanks Martin. I had already read the info at the link you posted but it was still a good review. Turns out, it was my fault... I created two config files, one for testing and one for production. I copy/pasted the same URL for both...smh. After changing the URL for the production config file my program connects. Haha. Thanks for your reply.

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C# Host key does not match configured key fingerprint