Abstract: A digital signature method and a verification method for a digital signature are provided. The digital signature method includes configuring a processor of an electronic device to: obtain, from a memory, to-be-signed data and a private key used by the electronic device for digital signing; extract a to-be-signed data segment from the to-be-signed data; perform a hash operation on the to-be-signed data segment to obtain a first digest value; encrypt the first digest value with the private key to generate signature data; and append the signature data to the to-be-signed data to generate to-be-verified data.

Abstract: A method of displaying a picture for an electronic device with picture display function includes determining whether a resolution of a picture inputted into the electronic device is greater than a resolution of a display device of the electronic device, displaying the picture in the display device when the resolution of the picture is smaller or equivalent to the resolution of the display device, and reducing the resolution of the picture and then displaying the reduced picture in the display device when the resolution of the picture is greater than the resolution of the display device.