Tadbir Urbanisme: files submitted since yesterday no longer open for the case officers

Tadbir Urbanisme is a fictional public agency that processes building permit applications for the region. Architects upload their plans on depot.e-tadbir.ma (an application with the role tadbir-depot-role); case officers view them in the internal review tool (role tadbir-instruction-role). The files are in the S3 bucket tadbir-dossiers-urbanisme.

Yesterday at 16:00, the security team applied the internal audit's recommendation: encrypt the files with a KMS key managed by the agency. This morning, case officers report that every file submitted since yesterday afternoon is “unreadable”. Review deadlines are set by law: every lost day counts.

You are the agency's cloud engineer, with the AWS CLI v2 (region eu-west-3, administrator profile).