status_t element_pow_int(element_t c, element_t a, integer_t b)
{
GroupType type = a->type;
// TODO: c (type) = a (type) ^ b (ZR)
LEAVE_IF( c->isInitialized != TRUE || a->isInitialized != TRUE, "uninitialized argument.");
EXIT_IF_NOT_SAME(c, a);
LEAVE_IF(b == NULL, "uninitialized integer.");
status_t result = ELEMENT_OK;
LEAVE_IF( c->type != type, "result initialized but invalid type.");
switch(type) {
case ZR: bn_mxp(c->bn, a->bn, b, a->order);
break;
case G1: g1_mul(c->g1, a->g1, b);
break;
case G2: g2_mul(c->g2, a->g2, b);
break;
case GT: if(bn_is_zero(b)) gt_set_unity(c->gt);
else gt_exp(c->gt, a->gt, b);
break;
default:
result = ELEMENT_INVALID_TYPES;
break;
}
return result;
}
status_t element_pow_zr(element_t c, element_t a, element_t b)
{
GroupType type = a->type;
// c (type) = a (type) ^ b (ZR)
LEAVE_IF( c->isInitialized != TRUE || a->isInitialized != TRUE, "uninitialized argument.");
EXIT_IF_NOT_SAME(c, a);
LEAVE_IF(a->isInitialized != TRUE, "invalid argument.");
LEAVE_IF(b->isInitialized != TRUE || b->type != ZR, "invalid type.");
if(type == ZR) {
bn_mxp(c->bn, a->bn, b->bn, a->order);
}
else if(type == G1) {
g1_mul(c->g1, a->g1, b->bn);
}
else if(type == G2) {
g2_mul(c->g2, a->g2, b->bn);
}
else if(type == GT) {
if(bn_is_zero(b->bn))
gt_set_unity(c->gt); // GT ^ 0 => identity element (not handled by gt_exp)
else
gt_exp(c->gt, a->gt, b->bn);
}
else {
return ELEMENT_INVALID_TYPES;
}
return ELEMENT_OK;
}
status_t element_init_GT(element_t e)
{
gt_inits(e->gt);
bn_inits(e->order);
gt_set_unity(e->gt);
g1_get_ord(e->order);
e->isInitialized = TRUE;
e->type = GT;
return ELEMENT_OK;
}
