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Android data channel ciphers

Posted: Tue Sep 07, 2021 8:48 am
by knew2vpn
good day,

Wanted to test if OpenVPN performance can be improved on my Android phone by using a differrent cipher in particular Chacha20-Poly1305 as my phone cannot hardware accelerate the AES ciphers so maybe chance to improvement with non AES ciphers!

In Access server advanced setting I changed my Allowed data channel ciphers to Chacha20-Poly1305:AES-256-GCM:AES-128-GCM:AES-256-CBC but still only uses second prefered option AES-256-GCM

I try to change Allowed data channel ciphers to only Chacha20-Poly1305 but then OpenVPN connect app logs an error "Data channel cipher negotiation failed (no shared cipher)"

so looks like my phone or app cannot support this.

My question: is the choice to use this cipher not supported by the OpenVPN Connect app, or is it limited by my phone itself such as hardware or android version?

Thanks you for reading my problem

Re: Android data channel ciphers

Posted: Tue Sep 21, 2021 11:34 am
by openvpn_inc
Hello knew2vpn,

OpenVPN Access Server 2.9 supports chachapoly if you configure it.

The client must also be configured to use that cipher. You may need to redownload the connection profile to get this configuration parameter in the client profile. That doesn't get updated dynamically.

Your client must also be able to support the chachapoly cipher. As I know, OpenVPN Connect v3.2 doesn't support it. But v3.3 does.

Kind regards,

Re: Android data channel ciphers

Posted: Fri Sep 24, 2021 11:39 am
by knew2vpn
Thanks for reply

I suspect my problem is that OpenVPN connect version I am using is 3.2.5 not 3.3

Sadly 3.3 is not currently available in play store UK so I'll await update