Abstract: The present invention discloses a method for transmitting an authentication password by a mobile terminal, a method for acquiring an authentication password by an authentication server side, an authentication server side and a system, wherein the method for transmitting an authentication password by a mobile terminal comprises the following steps: an original authentication password is mapped according to a set rule into at least one of the following three: pixel values of certain pixel sets on said pictures or picture sequence, the displaying order of the pictures in the picture sequence, and the displaying interval between the pictures in the picture sequence; wherein, when said original authentication password is mapped to include the displaying order of each picture, each picture has different pixel characteristics; and said pictures or picture sequence is displayed on a display screen of said mobile terminal.