Encryption techniques for broadcast communication

A broadcast technique for encrypted communication is proposed that offers high levels of security with high transmission efficiency. Any encryption algorithm can be used without significantly degrading ciphertext length. The proposed scheme can use parallel processing techniques to realize rapid encryption speeds. Plaintext is processed to yield one common component and as many individual components as there are receivers. Because the common component is used for all receivers, the ciphertext is relatively short. If a public key cryptosystem is used, any receiver´s decrypted plaintext can be compared with that of another receiver, thus preventing malicious sender attack