Does Shamir Secret Sharing provide integrity? Shamir secret sharing splits into t number of shares with a t-threshold. However, I can find no information online if this scheme provide integrity (or authentication for that matter, which I assume it does not). 

Can an adversary forge a share? If not, what hard problem is he faced with. Is it due to the share should be indistinguishable from random (psuedorandom)?
By Lagrange interpolation...


  Does Shamir Secret Sharing provide integrity? 


No


  Can an adversary forge a share?


Yes