Embodiments of the present invention relate to password authentication. According to an embodiment of the present invention, a password associated with a user identification is received from a user device. The password is authenticated based on a preset relationship between a seed password and a graphical password associated with the user identification. The seed password consists of a string of characters. The graphical password is a directed path traversing all keys of a keypad in an order. Each of the keys represents one of the characters and is associated with an order number according to the order of the keys being traversed. The preset relationship is that the password consists of respective order numbers associated with respective keys representing corresponding characters of the seed password.