Securing access control in large-scale Internet of Things (IoT) deployments requires mechanisms that adapt to risk while preserving low latency for benign traffic. Permissioned blockchains such as Hyperledger Fabric offer auditability through smart contracts, but static endorsement policies impose the same validation depth on all requests, regardless of security posture. We propose a risk-adaptive enforcement layer for Hyperledger Fabric that couples an off-chain LSTM-based risk oracle with deterministic on-chain checks. The oracle assigns each request to a tier (Low, Moderate, High) and issues a signed attestation bound to the client identity and target key/version. Endorsing peers verify the attestation in chaincode and enforce tier-conditioned SBE policies without modifying the ordering service or consensus. Experiments on a Fabric testbed show that tier-conditioned endorsement strengthens validation for higher-risk requests while retaining low confirmation latency for benign workloads.

翻译：在大规模物联网部署中保障访问控制安全，需要既能适应风险又能为良性流量保持低延迟的机制。Hyperledger Fabric 等许可型区块链通过智能合约提供审计能力，但静态背书策略对所有请求施加相同的验证深度，而不考虑其安全态势。我们提出一种 Hyperledger Fabric 的风险自适应执行层，将基于链下 LSTM 的风险预言机与确定性链上检查相结合。该预言机将每个请求划分为一个层级（低、中、高），并签发绑定至客户端身份及目标键/版本的签名证明。背书节点在链码中验证该证明，并实施基于层级条件的 SBE 策略，无需修改排序服务或共识机制。在 Fabric 测试平台上的实验表明，基于层级条件的背书在强化高风险请求验证的同时，对良性工作负载保持了较低的确认延迟。