void GCM_finish()

in src/gcm.c [283:303]

• 17 lines of code
• 4 McCabe index (conditional complexity)

void GCM_finish(gcm *g,char *tag)
{
    /* Finish off GHASH and extract tag (MAC) */
    int i;

    GCM_wrap(g);

    /* extract tag */
    if (tag!=NULL)
    {
        AES_ecb_encrypt(&(g->a),g->Y_0);        /* E(K,Y0) */
        for (i=0; i<16; i++) g->Y_0[i]^=g->stateX[i];
        for (i=0; i<16; i++)
        {
            tag[i]=g->Y_0[i];
            g->Y_0[i]=g->stateX[i]=0;
        }
    }
    g->status=GCM_FINISHED;
    AES_end(&(g->a));
}