Rephasing Invariance and Hierarchy of the CKM Matrix

We identified a set of four rephasing invariant parameters of the CKM matrix. They are found to exhibit hierarchies in powers of ${\lambda }^2$, from ${\lambda }^2$ to ${\lambda }^8$. It is shown that, at the present level of accuracy, only the first three parameters are needed to fit all available data on flavor physics.