Wow! Thanks for the quick fix! 

I take all I need to try it out is to pull and build the latest turbovnc 
and it should work?

Thanks again!

On Saturday, July 13, 2019 at 1:37:31 AM UTC-4, DRC wrote:
>
> I went ahead and implemented a new security configuration file directive 
> (permitted-cipher-suites), as well as a new Java TurboVNC Viewer system 
> property.  To achieve what you want, assuming you're using OpenSSL 1.0.2 or 
> later, you can add:
>
>     permitted-cipher-suites = 
> ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-ECDSA-AES256-SHA384
>
> to /etc/turbovncserver-security.conf.  That will prevent any ciphers other 
> than the two you listed from being used on the server end, regardless of 
> which ciphers are supported on the client end.  It will also effectively 
> disallow any of the TLS* security types, irrespective of the 
> permitted-security-types directive (because anonymous TLS uses different 
> ciphers.)
>
> As a belt-and-suspenders measure, you can also force the viewer to use 
> only those ciphers by setting
>
>     
> JAVA_TOOL_OPTIONS='-Dturbovnc.ciphersuites=TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384'
>
> in the environment on the client machine.
>
> The Xvnc log file, as well as the debug output from the viewer (-loglevel 
> 100) will reveal which ciphers are available and which cipher was 
> negotiated between server and client.
>
> DRC
> On 7/12/19 2:25 PM, Andy wrote:
>
> That would be awesome 
>
> Thanks!
>
> On Friday, July 12, 2019 at 2:46:20 PM UTC-4, DRC wrote: 
>>
>> I did some digging, and unfortunately there is no way to enable/disable 
>> OpenSSL ciphers on a system-wide or per-user basis.  They have to be 
>> configured on a per-application basis.  I will investigate adding a new 
>> TurboVNC security configuration file property for this, as it seems like 
>> something that would be generally useful. 
>>
>> On 7/12/19 10:03 AM, Andy wrote: 
>> > Hey so I have some strict requirements on what encryption ciphers we 
>> are 
>> > allowed to use. 
>> > 
>> > Basically I need it to use 
>> > either TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384 
>> > or TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384.  
>> > 
>> > From the viewer side I'm able to restrict the ciphers available to it 
>> by 
>> > modifying the java argument inside of the vncviewer script: 
>> >  and adding on the options 
>> > -Djava.security.properties=/opt/test/java.security.restictive 
>> > -Djavax.net.debug=ssl 
>> > 
>> > Now I get an SSL Handshake error when I try to connect - I think its 
>> > because Xvnc doesn't support the 2 ciphers that I'm trying to use.  
>> > 
>> > How would I go about enabling the two ciphers from the server (Xvnc) 
>> > side? I'd prefer to not have to recompile, but I'm not afraid to. 
>> > 
>> > 
>> > Thanks! 
>>
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