Antialiasing for picture passwords and other touch displays

摘要

Antialiasing for picture passwords and other touch displays is disclosed. In some embodiments a client device for authenticating a user is operable to obtain a sequence of input actions for an image and obtain a partial hash from a Proof of Knowledge (PoK) server where the partial hash is part of a hash used for authentication of the user. The client device is also operable to calculate a hash for the sequence and determine if a part of the hash matches the partial hash. If the part of the hash matches the partial hash, the client device sends a communication to the PoK server to authenticate the user based on the hash for the sequence of the one or more input actions and obtain a response indicating whether the user is authenticated. In this way, sending some hashes to the proof of knowledge server may not be necessary, saving resources.

主权项

1. A client device for authenticating a user, comprising:
one or more processors; and memory containing instructions executable by the one or more processors whereby the client device is operable to:
display an image at the client device;tile the image with an implicit grid comprising a plurality of grid elements;obtain a sequence of one or more input actions for the image according to the implicit grid;for each input action of the one or more input actions, determine one or more possible input actions;determine a plurality of possible sequences as the combination of one of the one or more possible input actions for each input action of the one or more input actions, wherein determining the one or more possible input actions for an input action comprises determining the one or more possible input actions for the input action using neighboring points of the input action;obtain a partial hash from a proof of knowledge server where the partial hash is part of a hash used for authentication of the user;calculate a hash for the sequence of the one or more input actions, wherein the calculated hash for the sequence of the one or more input actions is a hash of one of the plurality of possible sequences based on the sequence of the one or more input actions;determine if a part of the calculated hash matches the partial hash;in response to determining that the part of the calculated hash matches the partial hash, send a communication to the proof of knowledge server to authenticate the user based on the calculated hash for the sequence of the one or more input actions; andobtain a response from the proof of knowledge server based on the calculated hash for the sequence of the one or more input actions.