[Cryptography] Hohha quantum resistant end-to-end encryption protocol draft

[Alfie John]

On Thu, Nov 22, 2018 at 04:57:42PM +0000, Peter Fairbrother wrote:
> On 21/11/18 22:08, Bertrand Mollinier Toublet wrote:
> > 
> > > On Nov 21, 2018, at 7:31 AM, Ersin Taskin <hersintaskin at gmail.com> wrote:
> > > 
> > > [snip]
> > 
> > > So, I think PSK scheme is interesting.
> 
> I agree, and not just for use in a postquantum crypto setting.
> 
> In fact, I cannot think of another option for an ultimately secure messaging
> system. I wonder why it is not mainstream, I don't know a messaging system
> that is PSK based or has PSK option.

PSK doesn't work with Group Messaging. Initially PSK is fine when the
group is created, but what happens when a member leaves? Using your
model, every user will have to physically get together to roll over.
Large groups are going to be next to impossible to manage in a
sustainable way. Same goes for new members joining.  

Another concern I have with your system is the lack of Forward Secrecy.
It's almost 2019... let's not reinvent the mistakes of the past. There
are schemes out there that allow for what you're trying to aim for (and
more). Learn from them and try to incorporate their ideas into what
your project.

Alfie

-- 
Alfie John
https://www.alfie.wtf