Research On Internet Of Things Access Control Based On Blockchain And Attribute-based Encryption

With the continuous development of the Internet of Things(IoT)technology,its privacy protection has attracted more and more attention and access control is a significant method to achieve privacy protection of the IoT.However,most of the existing access control models are based on centralized models with the defects of poor security,vulnerability to attacks,and low degree of autonomy.Blockchain has been widely used in various fields,including the IoT access control,with the characteristics of decentralization,non-tampering,openness,transparency,programmable and peer-to-peer transactions.Among them,the characteristic of non-tampering in the blockchain provides a carrier for the worth transfer.This article carries on research in the attribute-based access control scheme,and improves the basic ciphertext-policy attribute-based encryption scheme in terms of decryption complexity,policy hiding and attribute revocation.We take full advantage of the characteristics of blockchain and integrate blockchain's storage and computing capabilities into the solution,such as the storage of public parameters,the generation of access logs and smart contracts to undertake calculations and automatic transfers.This article proposes two improved schemes,which based on access matrix and access tree,respectively.In the first scheme,composite order bilinear groups are used to realize the strategy hiding to achieve anonymity.Due to the poor computing power caused by the IoT terminal device lightweight,outsourced decryption is necessary,and the blockchain plays the role of outsourced validator and automatic transfer.The second scheme is based on the access tree and uses Lagrange Interpolation Polynomial to reconstruct the secret.Because Lagrangian interpolation is complicated to reconstruct the secret,we make use of an information table and symmetric encryption algorithm to implement the functions of outsourced partial decryption and attribute revocation,in which the blockchain acts as a trusted third party and undertakes partial decryption operations.This article studies the IoT access control and improves the attribute-based encryption scheme in combination with blockchain,effectively solving a series of problems faced by the IoT access control.