Support TLS 1.1 and TLS 1.2

[cologic]

Conveniently, all the code for this already exists in DC++. I even heard other DC clients support TLS 1.1 and 1.2 by now.

I'll just quote from https://www.dfranke.us/posts/2014-10-14-how-poodle-happened.html regarding the SSLv3 vulnerability (to which DC++ is immune, not supporting SSLv3):

The only correct way to fix POODLE is to disable SSL v3.0 altogether.

I think that last sentence will be mostly uncontroversial. Now, though, I am going to step onto my soapbox and say: disabling SSL v3.0 does not go far enough. It is time to aggressively deprecate as many old versions of TLS as possible. POODLE is not a one-off. It exploits a known mistake that has bitten us before. Many more similar mistakes still exist in TLS v1.0, and some time very soon one of them is going to bite us again.

Every revision of TLS contains fixes for dangerous errors committed by earlier versions. TLS v1.0 dictates the format of padding, preventing POODLE. v1.1 gets rid of IV-chaining, preventing BEAST. v1.2 introduces support for AEAD ciphersuites, providing an alternative to the dangerous MAC-then-encrypt construct. TLS v1.3 will eliminate the RSA handshake protocol[29], which lacks forward secrecy.

...

It’s time to put the cryptographic mistakes of the ’90s behind us.

[poy (poy)]

Fixed in DC++ 0.851.