A quantum random number generator

A quantum random number generator comprising: an entropy source comprising a laser source, a single photodiode configured for generating photo current based on received light from the laser source, where the photodiode has a non-unity quantum efficiency for allowing interference of the light from the laser source with a vacuum state to obtain entropy from the vacuum state, a transimpedance amplifier to convert the photo current into voltage, an analog-to-digital converter for converting the analog voltage to a digital output, a security proof which establishes a lower bound on the entropy from the vacuum state, a processing unit configured to convert the digital output from the analog-to-digital converter to random numbers based on the security proof.