This chapter shares a brief review of the principles of quantum cryptography. Then, attention is focused on quantum cryptography based on the quantum entanglement probability amplitudes where Bell’s theorem is applied to determine whether the transmission has been compromised by a third party, or not. An all-quantum probability protocol, independent of Bell’s theorem, is introduced to determine the fidelity and integrity of the transmission. Quantum teleportation of quantum states is described in detail using a detailed step-by-step example.