bigint_expmod_u(&m2, data, key->components[3], key->components[1]);
bigint_sub_s(&m1, &m1, &m2);
while(BIGINT_NEG_MASK & m1.info){
bigint_add_s(&m1, &m1, key->components[0]);
}
bigint_expmod_u(&m2, data, key->components[3], key->components[1]);
bigint_sub_s(&m1, &m1, &m2);
while(BIGINT_NEG_MASK & m1.info){
bigint_add_s(&m1, &m1, key->components[0]);
}