Abstract: An on-line measurement-error correction device and method for the inner profile of a special-shaped shell, including a fixing device. A vertical moving device is fixed at the top of the fixing device and connected with a horizontal moving device connected with a distance monitoring device, which is movable vertically and horizontally under the drive of the vertical and horizontal moving devices. The distance monitoring device includes a displacement monitoring element fixedly arranged on a fixing support hinged with an electric push rod configured to displace to drive the displacement monitoring element to deflect so as to change a monitoring direction. The displacement monitoring element is driven to deflect by the electric push rod of the distance monitoring device to change a monitoring direction, and a distance between each longitudinal section surface point on the inner surface of the special-shaped shell and the displacement monitoring element can be gradually measured.

Abstract: A blockchain-based public parameter generation method against backdoor attacks, includes: acquiring the hash values of L latest confirmed blocks on a blockchain, and the hash values of the L blocks and a count variable for generation are mapped to an element in a set G via a specified mapping to obtain the generated public parameter; L??, ? is the minimum number to guarantee blockchains' chain quality property; checking whether the generated parameter meets the condition, if not, discarding the parameter and updating the generated public parameter; if the condition is met, outputting the public parameter to the device that uses the public parameter. In this disclosure, the public parameters are random, since they are based on the latest confirmed blocks on the blockchain and are guaranteed by the computational power of the blockchain; the generation of public parameters is publicly verifiable and random.