This error is a known compatibility issue between Windows 10 1803's updated CNG (Cryptography Next Generation) components and older versions of Bitvise SSH. The root cause is a change in how the system handles key exchange data structures, which triggers the unexpected secretData->cbStruct error in Bitvise's CNG-based key exchange handler.

Here are two reliable solutions to resolve this, tested across multiple VPS environments:

1. Update Bitvise SSH to the Latest Version #

Bitvise has already patched this compatibility bug in newer releases. This is the most straightforward and long-term fix:

• Download the latest version of Bitvise SSH Client/Server from the official Bitvise website
• Install it over your existing version (no need to uninstall first)
• Repeat this on all affected VPS instances, then restart the SSH service (if using the server) or re-launch the client

2. Temporary Workaround (If You Can't Upgrade Immediately) #

If you need a quick fix before updating, modify the key exchange algorithms to avoid CNG-dependent ones:

• For Bitvise SSH Client:
  1. Open the client's settings window
  2. Navigate to Advanced > Key Exchange
  3. Uncheck all algorithms with ECDH in their name (e.g., ecdh-sha2-nistp256, ecdh-sha2-nistp384)
  4. Ensure only traditional DH algorithms like diffie-hellman-group-exchange-sha256 or diffie-hellman-group14-sha256 are enabled
  5. Save settings and reconnect to your VPS
• For Bitvise SSH Server:
  1. Open the server's configuration tool
  2. Go to SSH Settings > Key Exchange
  3. Make the same algorithm adjustments as above, then apply changes and restart the server service

Either of these steps should resolve the ComponentException error you're seeing across all your VPS.

内容的提问来源于stack exchange，提问作者Billy Adelphia