Why is 2PC (2-Party Computation) not used as any other primitive like Diffie-Hellman?
I'm not talking about the general secure computing, but some weaker security requirement or special case schemes.
A number of tricky methods for GC (Garbled Circuit) have been proposed like free-XOR, half-gate and so on. And recent promotions like TinyGarble, LEGO seem practical.
Is there any irreplaceable need for such primitives in the real world? Or is the GC the only way for MPC (Multi-Party Computation)?