To improve the security of EoC network traffic, the hybrid encryption scheme was presented. The relevant encryption algorithm was analyzed, and the hybrid encryption scheme was proposed for EOC downlink traffic encryption, in which ECC algorithm is taken to produce and encrypt session key, and Blowfish algorithm is improved to encrypt the broadband-authorized frame and downlink data. The security analysis show the encryption scheme can guarantee the integrity and confidentiality of the data in the EoC transmission process.