[Cryptography] WhatsApp: Why asymmetric key instead of symmetric keys?

[Ismail Kizir]

>>What problem would that solve?  The asymmetric keys work fine.

I also thought about using curve25519.
I downloaded it. Tested it. It is really simple to use.
But only 256 bits key space??
You are developing a "new" algorithm in 2016; and you are using a
fixed 256 bit key space.
It's surely enough for %99 percent of attackers. But, I am not sure
about resourceful attackers in long term.

Personal privacy is a very important subject.
A lot of people think about criminal cases.
I think about mass surveillance, storage and future decryption.
One day, one of our children will be the president and other one's
will be prime minister. It will be be in 20-30 years later.
I don't want when that day comes, someone resourceful who stored all
"most private" information about our children deciphers all those
information and use it against our children.
Every detail; from the first innocent love declaration to most
intimate secrets are transmitted via messaging  applications nowadays.
Maybe, I am ignorant, or paranoid. Maybe.
But I always prefer using strong symmetrical algorithms with enough
large key space whenever possible.

R's
Ismail

On Tue, Apr 26, 2016 at 5:46 PM, John Levine <johnl at iecc.com> wrote:
>>But I meant, "why not both"?
>>It's not difficult to design a protocol which also supports pre shared keys.
>
> What problem would that solve?  The asymmetric keys work fine.
>
> R's,
> John
>
>
>