An electronic device comprising: a sensing circuit; a memory; and a processor configured to: capture a plurality of authentication images comprising an iris of a user through the sensing circuit during a specific time, generate a preview image for each of the plurality of the authentication images by applying an image filter to the each of the plurality of authentication images such that sensitive information in the preview image is not recognized, wherein the image filter is a blur filter or a mosaic filter, output the preview image together with a guide through a display, wherein the guide includes information that directs an authentication target corresponding to the authentication image to be located at a specific distance from the sensing circuit, select at least one image from the plurality of authentication images based on at least one of a size of the iris, a size of an eye, a visibility, or a degree of opening of the eye in each of the authentication images, extract personal authentication information from the selected at least one image, determine whether the extracted personal authentication information is for registration or authentication based on a user interface being performed, when the extracted personal authentication information is for registration, store the extracted personal authentication information in the memory, and when the extracted personal authentication information is for authentication, perform an authentication based on the selected at least one image by comparing the extracted personal authentication information with personal authentication information stored in the memory, and wherein the image filter reduces a resolution of the authentication image or adds an effect, characterized in that a working environment of the electronic device includes a general area and a secure area, wherein the generation of the preview image and the guide and the authentication are performed in the secure area and the outputting the generated preview image and the guide is performed in the general area. a sensing circuit; a memory; and a processor configured to: capture a plurality of authentication images comprising an iris of a user through the sensing circuit during a specific time, generate a preview image for each of the plurality of the authentication images by applying an image filter to the each of the plurality of authentication images such that sensitive information in the preview image is not recognized, wherein the image filter is a blur filter or a mosaic filter, output the preview image together with a guide through a display, wherein the guide includes information that directs an authentication target corresponding to the authentication image to be located at a specific distance from the sensing circuit, select at least one image from the plurality of authentication images based on at least one of a size of the iris, a size of an eye, a visibility, or a degree of opening of the eye in each of the authentication images, extract personal authentication information from the selected at least one image, determine whether the extracted personal authentication information is for registration or authentication based on a user interface being performed, when the extracted personal authentication information is for registration, store the extracted personal authentication information in the memory, and when the extracted personal authentication information is for authentication, perform an authentication based on the selected at least one image by comparing the extracted personal authentication information with personal authentication information stored in the memory, and capture a plurality of authentication images comprising an iris of a user through the sensing circuit during a specific time, generate a preview image for each of the plurality of the authentication images by applying an image filter to the each of the plurality of authentication images such that sensitive information in the preview image is not recognized, wherein the image filter is a blur filter or a mosaic filter, output the preview image together with a guide through a display, wherein the guide includes information that directs an authentication target corresponding to the authentication image to be located at a specific distance from the sensing circuit, select at least one image from the plurality of authentication images based on at least one of a size of the iris, a size of an eye, a visibility, or a degree of opening of the eye in each of the authentication images, extract personal authentication information from the selected at least one image, determine whether the extracted personal authentication information is for registration or authentication based on a user interface being performed, when the extracted personal authentication information is for registration, store the extracted personal authentication information in the memory, and when the extracted personal authentication information is for authentication, perform an authentication based on the selected at least one image by comparing the extracted personal authentication information with personal authentication information stored in the memory, and wherein the image filter reduces a resolution of the authentication image or adds an effect, characterized in that a working environment of the electronic device includes a general area and a secure area, wherein the generation of the preview image and the guide and the authentication are performed in the secure area and the outputting the generated preview image and the guide is performed in the general area.