Thanks for elaborating. The 'other side' are the people currently working on the negotiated-ffdhe draft (which I assume are bright people too). The draft was l

Thanks for elaborating. The 'other side' are the people currently working on the negotiated-ffdhe draft (which I assume are bright people too). The draft was last updated a week ago (12 May 2015), so their considerations must be quite recent. I'm just trying to get a sense of pros and cons. Iirc, generating own groups has its problems too. For example, the Triple Handshake attack (https://www.secure-resumption.com/ https://www.secure-resumption.com/) could break TLS because implementations did not properly validate DH params. Allowing only some (set of) pre-defined (known good) params would have stopped that attack. To be clear, I'm certainly not arguing for or against using common groups. Just trying to get a complete picture. (And yes, based on current information I think too that using unique groups is the right approach.)