How to Specify Key Exchange Algorithms in 2022

Select SSH Server KEX Key Exchange Algorithms

Specify the Key Exchange algorithms available to the server that are offered to the client. The Key Exchange algorithms are offered to the client in the server’s default order unless specified. The default order will vary from release to release to deliver the best blend of security and performance. Specify the ciphers that the server can offer to the client by modifying the registry key szKexAlgoritms.

The key is:

• For Win x64: HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Georgia SoftWorks\GSW_SSHD\Parameters\szKexAlgoritms
• For Win x86: HKEY_LOCAL_MACHINE\SOFTWARE\Georgia SoftWorks\GSW_SSHD\Parameters\szKexAlgoritms

The following is the default list for Key Exchange Algorithms.
curve25519-sha256,curve25519-sha256@libssh.org,diffie-hellman-group18-sha512,diffie-hellman-group16-sha512,diffie-hellman-group-exchange-sha256,diffie-hellman-group14-sha256,ecdh-sha2-nistp521,ecdh-sha2-nistp384,ecdh-sha2-nistp256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1

The following is the list and order of all Key Exchange Algorithms available.
ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,curve25519-sha256,curve25519-sha256@libssh.org,diffie-hellman-group-exchange-sha256,diffie-hellman-group16-sha512,diffie-hellman-group14-sha256,diffie-hellman-group18-sha512,diffie-hellman-group-exchange-sha1,diffie-hellman-group1-sha1,diffie-hellman-group14-sha1Page

The list of Key Exchange Algorithms does not vary based the Enable/Disable value for FIPS 140-2 option.

The following is the procedure to change the registry key to specify the Key Exchange Algorithms available to the client.
1. Click the Start button at the bottom left corner of your screen
2. Click RUN
3. Type REGEDIT
4. Click OK
5. Select Registry Key:

• For Win x64: HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Georgia SoftWorks\GSW_SSHD\Parameters\szKexAlgoritms
• For Win x86: HKEY_LOCAL_MACHINE\SOFTWARE\Georgia SoftWorks\GSW_SSHD\Parameters\szKexAlgoritms

6. Select the menu item Edit and then click on Modify
7. Enter the new value for the szKexAlgoritms and click OK

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The new value will take effect when the GSW SSHD service is restarted

Related Documents:

• Restart SSH Server Service
• Learn more about the GSW SSH Server for Windows
• SSH Server with FIPS 140-2
• Approved SSH Security Key Exchange Algorithms
• GSW Business Tunnel - SSH Tunnel
• SSH Client for Android

Back to SSH Server FAQ

Document Number: FAQ-SSH-EX017001081519
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