Research on Downstream Encryption Scheme Based on Timestamp in GEPON Network

Gigabit Ethernet Passive Optical Network (GEPON) is considered as the best access means for Triple Play due to its simple structure and low costs. However, the point-to-multi-points tropology endangers its security and users' privacy. By investigating the safety threats in GEPON, a timestamp-based encryption is presented. The timestamp used in ranging is extracted and embedded into Advanced Encryption Standard (AES) algorithm, therefore the encryption keys vary with time due to the different ranging time. this paper presents a new encryption method based on timestamp function. This method combines AES algorithm with timestamp to form keys for encrypting downstream data. By adding an encryption/decryption module in both Optical Line Terminal (OLT) and Optical Network Unit (ONU), unsafe keys transmission through channel can be avoided. In addition, the extraction and synchronization of timestamp, along with the dynamic update and synchronization of keys, are released. Experimental results show that the method has the advantages of low delay, high throughput and high security compared with the traditional encryption algorithm. After the theoretical analysis, the simulation results of proposed scheme are given, proving its validity. Index Terms –timestamp; gigabit ethernet passive optical network (GEPON); advanced encryption standard (AES) algorithm; encryption.