Quantum-augmentable hybrid encryption system and method

A hybrid encryption scheme links a first public key encryption (PKE) scheme with a second PKE scheme through a true random or pseudo-random element, which is used by a sender to encapsulate a symmetrically encrypted message and its associated symmetric key to generate a pair of ciphertexts for transmission to a recipient. The recipient decrypts and decapsulates the ciphertexts, retrieves the random element, and may conduct one or more verification steps to ensure that the ciphertexts were well-formed, and to detect any re-encryption or encapsulation attacks. To encrypt a message, the message and initial random value are encrypted with a symmetric key to provide an intermediate ciphertext. The symmetric key and the encrypted message-value are each encapsulated by distinct algorithms using distinct values derived from the initial random value, such as different hashes, and public keys to provide first and second ciphertexts.