The extraction of the phase from an electronic wavepacket has a lot of applications ranging from the measurement of attosecond pulses to the determination of the delay in photoemission. In this talk we present some ideas about different methods to extract this phase. I will discuss different strategies to directly characterize the CEP of an isolated attosecond pulse (IAP) by numerically simulating the tunneling ionization of a hydrogen atom in a combined IAP and phase-stabilized circularly polarized IR laser pulse. The fine modulations of the combined laser fields, due to the variation of the CEP of the IAP, are exponentially enlarged onto the distinct time-dependent tunneling ionization rate. Electrons released at different time with distinct tunneling ionization rates are angularly streaked to different directions. By measuring the resulting photoelectron momentum distribution we can characterize the CEP of an IAP which will open the possibility of capturing sub-EUV-cycle dynamics.