How Little is Enough? Implementation and Evaluation of a Lightweight Secure Firmware Update Process for the Internet of Things

Design and evaluation of a method for Over-the-Air firmware updates for IoT devices

“…MOAP, a Multihop Over-the-Air Programming [50] mechanism focused on being memory and energy efficient, was frequently used for update dissemination as well. In terms of newer embedded operating systems, RIOT OS [51] and ARM mbed [52] are often cited in surveys [21,23,41,53,54] and used by solutions [11,55].…”

“…If the new firmware is already installed, a rollback might be needed. Many works argue the importance of keeping the last functioning version of the firmware in a separate storage partition for this purpose [7,11,42,55]. The rollback process must be supported by the bootloader.…”

“…To ensure confidentiality and integrity of the firmware, two works [59,62] suggest a method where the firmware is split into blocks used for hash chaining and each hash is encrypted before being sent to a device, where it is decrypted and reassembled. Schmidt et al [11] propose different types of firmware packages with combinations of security mechanisms, balancing how secure or fast the update should be. A technique used in many solutions to guarantee integrity is signing of the package [11,15,55,63].…”

“…Schmidt et al [11] propose different types of firmware packages with combinations of security mechanisms, balancing how secure or fast the update should be. A technique used in many solutions to guarantee integrity is signing of the package [11,15,55,63].…”

“…Being such an important part of a device life cycle, software update brings its own challenges. Much of its hardships were described in previous works [6,7,8] with possible solutions discussed by other authors [9,10,11]. Most of these solutions are proposed or implemented using technologies developed for constrained devices that are incorporated with well established Internet technologies.…”