When I try to connect to a new install of UVNC I get a message saying "authentication rejection"
In the new install I do have my rc4.key that I have used for many years.
I also have:
20121120_Server_ClientAuth.pubkey
20121120_Viewer_ClientAuth.pkey
All three files are in the same folder that UVNC is installed in.
Years ago I think I remember the rc4.key had to be included in the config but I don't see a way to do that now.
What do I need to do to get it recognized?
Thank you,
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A new stable version, UltraVNC 1.6.4.0 and UltraVNC SC 1.6.4.0 have been released: https://forum.uvnc.com/viewtopic.php?t=38095
Feedback is always welcome
2025-12-05: Celebrating the 23th anniversary of the UltraVNC (26th anniversary since the laying of the foundation stone): https://forum.uvnc.com/viewtopic.php?t=38130
2025-12-03: Could you please complete our poll/survey? Renaming UltraVNC files and service to be more clear: https://forum.uvnc.com/viewtopic.php?t=38128
There was a problem to vote, it is solved now! Thanks in advance!
2025-12-02: We need help: English Wikipedia UltraVNC page has been requested to deletion: https://forum.uvnc.com/viewtopic.php?t=38127
Any help is welcome to improve the UltraVNC page and/or to comment on the Wikipedia Talk page
2025-05-06: Forum password change request: https://forum.uvnc.com/viewtopic.php?t=38078
2023-09-21: Important: Please update to latest version before to create a reply, a topic or an issue: https://forum.uvnc.com/viewtopic.php?t=37864
Development: UltraVNC development is always here... Any help is welcome
Feedback is welcome
Join us on social networks and share our announcements:
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authentication rejection
- Rudi De Vos
- Admin & Developer

- Posts: 6986
- Joined: 2004-04-23 10:21
- Contact:
Re: authentication rejection
rc4 is the key for the old encryption module (MSRC4Plugin)
The new encryption (SecureVNCPlugin) use
-20121120_Server_ClientAuth.pubkey
-20121120_Viewer_ClientAuth.pkey
On the viewer and server you need to select to use the SecureVNCPlugin plugin.
20121120_Server_ClientAuth.pubkey need to be in the folder where you start winvnc.exe
20121120_Viewer_ClientAuth.pkey need to be copied to the viewer pc, in the folder of vncviewer.exe
see also
https://uvnc.com/docs/documentation-1-3 ... ption.html
The new encryption (SecureVNCPlugin) use
-20121120_Server_ClientAuth.pubkey
-20121120_Viewer_ClientAuth.pkey
On the viewer and server you need to select to use the SecureVNCPlugin plugin.
20121120_Server_ClientAuth.pubkey need to be in the folder where you start winvnc.exe
20121120_Viewer_ClientAuth.pkey need to be copied to the viewer pc, in the folder of vncviewer.exe
see also
https://uvnc.com/docs/documentation-1-3 ... ption.html
UltraVNC links (join us on social networks):
- Website: https://uvnc.com/
- Forum: https://forum.uvnc.com/
- GitHub sourcecode: https://github.com/ultravnc/UltraVNC
- Mastodon: https://mastodon.social/@ultravnc
- Bluesky/AT Protocol: https://bsky.app/profile/ultravnc.bsky.social
- Facebook: https://www.facebook.com/ultravnc1
- X/Twitter: https://x.com/ultravnc1
- Reddit community: https://www.reddit.com/r/ultravnc
- OpenHub: https://openhub.net/p/ultravnc
- uvnc2me: https://uvnc2me.com/
- Website: https://uvnc.com/
- Forum: https://forum.uvnc.com/
- GitHub sourcecode: https://github.com/ultravnc/UltraVNC
- Mastodon: https://mastodon.social/@ultravnc
- Bluesky/AT Protocol: https://bsky.app/profile/ultravnc.bsky.social
- Facebook: https://www.facebook.com/ultravnc1
- X/Twitter: https://x.com/ultravnc1
- Reddit community: https://www.reddit.com/r/ultravnc
- OpenHub: https://openhub.net/p/ultravnc
- uvnc2me: https://uvnc2me.com/
