From TightVNC's website:
TightVNC encrypts VNC passwords sent over the net, the rest of the traffic is sent as is, unencrypted (for password encryption, VNC uses a DES-encrypted challenge-response scheme, where the password is limited by 8 characters, and the effective DES key length is 56 bits)
VNC security is weak, but just wonder how many people will spend time to hack it?
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NoMachine is another good choice and is feature rich with good encryption. But the software is large, complex and a bit confusing.
NoMachine NX protocol encryption is implemented using OpenSSL TLS/SSL
It uses Windows username/password though. Remote user probably wouldn't give it to technician.
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join.me is free too. But you need to create an acount.
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found another program called
AeroAdmin, free for personal and business,works very much like TeamViewer.
http://www.aeroadmin.com/en/security.html
*** Tested. Screen quality is terrible and speed is slow.
