int GCM_add_header()

in src/gcm.c [196:214]

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

int GCM_add_header(gcm* g,const char *header,int len)
{
    /* Add some header. Won't be encrypted, but will be authenticated. len is length of header */
    int j=0;
    if (g->status!=GCM_ACCEPTING_HEADER) return 0;

    while (j<len)
    {
        for (int i=0; i<16 && j<len; i++,j++)
        {
            g->stateX[i]^=header[j];
            g->lenA[1]++;
            if (g->lenA[1]==0) g->lenA[0]++;
        }
        gf2mul(g);
    }
    if (len%16!=0) g->status=GCM_ACCEPTING_CIPHER;
    return 1;
}