Spin-torque nano-oscillators (STNOs) are nanoscale devices with wide-band-frequency tunability. Their multifunctional rf properties are well suited to define schemes for wireless communications that use basic protocols for data transmission, such as amplitude-, frequency-, and phase-shift keying (ASK, FSK, and PSK, respectively). ASK and FSK are demonstrated for STNOs, but the implementation of PSK is more challenging because the STNO phase suffers from large fluctuations. Here, we introduce a special PSK technique for STNOs by combining their modulation and injection-locking functionality. The concept is validated using magnetic-tunnel-junction-based vortex STNOs for injection locking at 2f and f/2, showing phase shifts up to 0.70πrad and data-transmission rates up to 4 Mbit/s. Quadrature phase-shift keying and analog phase modulation are also implemented, where the latter is employed for voice transmission over a distance of 10 m. This demonstrates that the STNO's phase noise and output power meet the requested performances for operations in existing communication schemes. © 2021 American Physical Society.