Abstract: A system and method provide a hybrid communication scheme that achieves high communication rates with post-quantum computational security guarantees. Messages to be securely communicated are first mixed using an individually secure encoding, such as a linear network code, and some of the encoded messages are further encrypted. The encrypted and unencrypted messages are sent via different communications channels. Each unencrypted message becomes almost as secure as the encrypted messages because of the pre-mixing, since decoding any one of the messages requires all of the messages, including the encrypted messages. Thus, a very few encrypted messages may be used, allowing the rate of communication to approach one as the number of channels increases. This is particularly beneficial when a classical public-key cryptosystem can only be used in part of the data transmitted or stored, in the presence of noisy channels, in distributed data storage, and other applications.