BLS optimization

[ChihChengLiang]

What is wrong?

There's a need to optimize BLS verifying process. Here lists some possible actions items.

• Optimize through the math part: Vitalik has a short cut for the pairing and final exponentialization
• Profiling to identify the hotspot
• Some function rewrite options (from the offline discussion of @hwwhww and @changwu-tw )
  • Cython, see Improving performance of the Library with Cython #50
  • gmp
  • sage: only py2 support 😢
  • Numba

How can it be fixed

[pipermerriam]

Numba and Cython are likely to not be trivially easy to reap benefits as they won't support arbitrarily large integers (likely nothing above 64bit).