DataFlex

Get the SSH Server Host Key Fingerprint

Demonstrates the Chilkat Ssh.GetHostKeyFP method, which returns the connected server's host-key fingerprint. The first argument is the hash algorithm (for example SHA256 or MD5), the second controls whether the key type is included, and the third controls whether the hash name is included. The digest is Base64 without trailing padding.

Background: The host-key fingerprint identifies the server. Comparing it against a known-good value is how a client implements host-key pinning — detecting man-in-the-middle attempts or a changed server key. SHA256 is the modern default; MD5 fingerprints are still seen in older tooling but are weaker.

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Use ChilkatAx-win32.pkg

Procedure Test
    Boolean iSuccess
    Handle hoSsh
    Integer iSshPort
    Boolean iIncludeKeyType
    Boolean iIncludeHashName
    String sFingerprint
    String sTemp1
    Boolean bTemp1

    Move False To iSuccess

    //  Demonstrates the Ssh.GetHostKeyFP method, which returns the server's host-key fingerprint.
    //  The 1st argument is the hash algorithm, the 2nd controls whether the key type is included,
    //  and the 3rd controls whether the hash name is included.

    Get Create (RefClass(cComChilkatSsh)) To hoSsh
    If (Not(IsComObjectCreated(hoSsh))) Begin
        Send CreateComObject of hoSsh
    End

    //  Connect to the SSH server.  Port 22 is the usual SSH port.
    Move 22 To iSshPort
    Get ComConnect Of hoSsh "ssh.example.com" iSshPort To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoSsh To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    //  Get the SHA256 fingerprint, including the key type and hash name in the result.
    Move True To iIncludeKeyType
    Move True To iIncludeHashName
    Get ComGetHostKeyFP Of hoSsh "SHA256" iIncludeKeyType iIncludeHashName To sFingerprint
    Get ComLastMethodSuccess Of hoSsh To bTemp1
    If (bTemp1 = False) Begin
        Get ComLastErrorText Of hoSsh To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    Showln "Host key fingerprint: " sFingerprint

    Send ComDisconnect To hoSsh


End_Procedure