Erasure coding is the underlying implementation technology of double fault tolerance for Redundant Array of Independent Disks-6 （RAID-6）， and the performance of erasure code is one of the important factors affecting the performance of RAID-6. Aiming at the problems of I/O imbalance and slow data recovery of array erasure codes commonly used in RAID-6， an Exclusive OR （XOR） based hybrid array code was proposed， namely J-code. A new parity check generation rule was adopted by J-code. Firstly， two-dimensional array constructed from the original data was used to calculate the diagonal parity bits and construct a new array. Then， the positional relationship between the data blocks in the new array was used to calculate the anti-diagonal parity bits. Besides， the original data and part of the parity bits were stored by J-code on the same disk， which reduced the number of XOR operations in the process of encoding and decoding as well as the number of data blocks read in the recovery process of a single disk， thereby reducing the complexity of encoding and decoding as well as the I/O cost for repairing a single disk， and alleviating the phenomenon of disk hotspot concentration. Simulation results show that compared with array codes such as RDP （Row-Diagonal Parity） and EaR （Endurance-aware RAID-6）， J-code has the encoding time reduced by 0.30% to 28.70%， the single disk failure repair time reduced by 2.23% to 31.62%， and the double disk failure repair time reduced by 0.39% to 36.00%.

For the low performance of hot data access in distributed storage， a load balancing method based on Local Repair Code （LRC） was proposed， which uses coding to avoid centralized access of nodes and improve the access efficiency of hot data. Firstly， a kind of special LRC suitable for small-scale storage systems was constructed by using Balanced Incomplete Block Design （BIBD）， and it was able to provide multiple access methods for encoded data. Secondly， based on Reed Solomon （RS） code and random array code， LRC was extended to a larger scale situation， and it was able to meet certain fault tolerance requirements of the storage system. Finally， a hot data access algorithm was given to reduce the pressure of hot data access， and combined with a reasonable data layout scheme， the load balancing of the storage system in high-frequency access scenarios was achieved. Theoretical analysis and experimental results show that the proposed method can achieve load balancing with very small cost， and its effect is significantly better than that of the load balancing method implemented by multiple copies and Maximum-Distance-Separable （MDS） code in the traditional method. Especially， the proposed method solves the load imbalance problem caused by uneven access to hot and cold data， which can effectively improve the access efficiency of hot data storage systems.

Focused on the issue that the current online conference digital review system cannot ensure the privacy of reviewers’ opinions and obtain safe and reliable results at the same time， a privacy computing based design scheme of digital review system for online conference was proposed. Firstly， the review data were shared secretly through the encoding matrix of Reed-Solomon （RS） code to obtain secret shares， and the hash code of each party’s review data was submitted to the organizer as a stub to prevent denial. Secondly， the secret shares were cooperatively computed by the monotone expansion matrix， one encoding matrix， to obtain the voting results. Finally， the parity check matrix was used to check whether there was a sharing error or tampering behavior of the secret shares in the process of multi-party cooperative computing. Theoretical analysis and simulation show that the proposed scheme can realize the privacy computing function in the digital review system for small- and medium-sized online conferences.