Portable Implementation of Postquantum Encryption Schemes and Key Exchange Protocols on JavaScript-Enabled Platforms

Algorithm 3

Gentleman-Sande (GS) inverse number theoretic transform ().

Input: Polynomial , and a LUT in bit-reversed order

Output: Polynomial

1  ;

2  for   to  by  do

3;

4for    to    do

5;

6;

7for    to    do

8;

9;

10;

11;

12endfor

13;

14endfor

15;

16 endfor

17 for    to    do

18;

 19 endfor

20 return  .