Func_ComputeKeysRingRelinFFT problem

[Jyun-Neng]

At line 424 in ltv.cpp file (src folder), f = ft*p + 1.
Not all coefficients in f are assigned ft[i]*p+1.
In fact, only f[0] is ft[0]*p+1.
Others, for example, f[1] is ft[1]*p.

[yarkindoroz]

It is the correct use case. The logic is that a key f with property f =2f'+1 is used to extract message after multiplications and mod 2 operation. For instance; f*m = 2f'm + m, if we take mod 2 we have m as result. If all the elements have +1, we will not be able to have m. We will have m distributed to all the slots as m+mx+mx^2+mx^3 ... . This will mess up the computation algorithmically.

[Jyun-Neng]

Thank you! I understand!