Algorithm 1.  $Kyber\_CPA\_\mathrm{key}\left(\right):\mathrm{key} \mathrm{generation}$

1. $\mu ,\delta :\leftarrow {\left\{0,1\right\}}^{256}$

2. $N~R_t^{i\times i}:=S(b)$

3. $(g,j)~{\beta }_{\eta }^i\times {\beta }_{\eta }^i:=S(\delta )$

4. $f:=Com{p}_t(Ng+j,{\mathrm{q}}_t)$

5: return $(bi:=(f,b),gi:=g)$