} // sqrtM1 is 2^((p-1)/4), which squared is equal to -1 by Euler's Criterion. var sqrtM1 = &Element{1718705420411056, 234908883556509, 2233514472574048, 2117202627021982, 765476049583133} // SqrtRatio sets r to the non-negative square root of the ratio of u and v. // // If u/v is square, SqrtRatio returns r and 1. If u/v is not square, SqrtRatio // sets r according to Section 4.3 of draft-irtf-cfrg-ristretto255-decaf448-00, // and returns r and 0. func (r *Element) SqrtRatio(u, v *Element) (R *Element,...