Patent ID: 10243735

Abstract:
Communication devices and a method of providing secure electronic content are general described. A plainmodulation containing user content is encrypted using a modulation key to form a ciphermodulation having a different magnitude and/or phase than the plainmodulation. Symbol representations of the plainmodulation and ciphermodulation in a QAM constellation are different. The ciphermodulation symbol representation is in a location non-coincident with an expected QAM constellation symbol. The symbol location of different plainmodulations when encypted using different modulation keys may be the same such that the corresponding ciphermodulation symbol representations are co-located. Different modulation keys are used for different plainmodulations, with a modulation key change occurring after transmission of a predetermined number of ciphermodulations and/or time. The modulation key and/or change is transmitted to enable coherent demodulation of the ciphermodulation to be performed. Multiple plainmodulations may be encrypted into a single ciphermodulation and/or a single plainmodulation may be encypted across multiple ciphermodulations.