ANTIALIASING FOR PICTURE PASSWORDS AND OTHER TOUCH DISPLAYS

• US 20150349957A1
• Filed: 06/02/2015
• Published: 12/03/2015
• Est. Priority Date: 06/02/2014
• Status: Active Grant

• Current Assignee: Antique Books, Inc
• Original Assignee: Antique Books, Inc
• Inventors: Thibadeau, Robert H. Sr., Donnell, Justin D., Thibadeau, Robert Jr.
• Granted Patent: US 9,490,981 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 21/36 by graphic or iconic representation
• CPC Class Codes: G06F 2221/2133 Verifying human interaction, e.g., Captcha
• CPC Class Codes: G06F 3/04812 Interaction techniques based on cursor appearance or behaviour, e.g. being affected by the presence of displayed objects
• CPC Class Codes: G06F 3/04842 Selection of displayed objects or displayed text elements G06F3/0482 takes precedence
• CPC Class Codes: H04L 2209/20 Manipulating the length of blocks of bits, e.g. padding or block truncation
• CPC Class Codes: H04L 63/083 using passwords cryptographic mechanisms or cryptographic arrangements for entity authentication using a predetermined code H04L9/3226
• CPC Class Codes: H04L 63/0853 using an additional device, e.g. smartcard, SIM or a different communication terminal cryptographic mechanisms or cryptographic arrangements for entity authentication involving additional secure or trusted devices H04L9/3234
• CPC Class Codes: H04L 63/0861 using biometrical features, e.g. fingerprint, retina-scan cryptographic mechanisms or cryptographic arrangements for entity authentication using biological data H04L9/3231
• CPC Class Codes: H04L 63/0884 by delegation of authentication, e.g. a proxy authenticates an entity to be authenticated on behalf of this entity vis-à-vis an authentication entity
• CPC Class Codes: H04L 9/3218 using proof of knowledge, e.g. Fiat-Shamir, GQ, Schnorr, ornon-interactive zero-knowledge proofs
• CPC Class Codes: H04L 9/3236 using cryptographic hash functions
• CPC Class Codes: H04L 9/3239 involving non-keyed hash functions, e.g. modification detection codes [MDCs], MD5, SHA or RIPEMD
• CPC Class Codes: H04L 9/3242 involving keyed hash functions, e.g. message authentication codes [MACs], CBC-MAC or HMAC

Abstract

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.

Claims

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;

obtain a sequence of one or more input actions for an image displayed at the client device;

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;

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 a proof of knowledge server to authenticate the user based on the calculated hash for the sequence of the one or more input actions; and

obtain a response from the proof of knowledge server based on the calculated hash for the sequence of the one or more input actions.

2. The client device of claim 1 wherein the calculated hash for the sequence of the one or more input actions is a hash of one of a plurality of possible sequences based on the sequence of the one or more input actions.

3. The client device of claim 2 further operable to:

calculate a hash of another of the plurality of possible sequences;

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 of another of the plurality of possible sequences; and

obtain a response from the proof of knowledge server based on the calculated hash of another of the plurality of possible sequences.

4. The client device of claim 3 further operable to:

for each possible sequence in the plurality of possible sequences, perform the calculate, determine, send, and obtain steps for that possible sequence

5. The client device of claim 2 wherein being operable to obtain the one or more input actions comprises being operable to:

tile the image with an implicit grid comprising a plurality of grid elements; and

obtain the one or more input actions according to the implicit grid.

6. The client device of claim 5 further operable to:

for each input action of the one or more input actions, determine one or more possible input actions; and

determine the 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.

7. The client device of claim 6 wherein being operable to determine the one or more possible input actions for an input action comprises being operable to determine the one or more possible input actions for the input action using the neighboring points of the input action.

8. The client device of claim 7 wherein the neighboring points of the input action are neighboring points of the input action on the implicit grid.

9. The client device of claim 8 wherein the implicit grid is hexagonal and each input action has six neighboring points comprising the vertices of a hexagon on the implicit grid centered at the input action.

10. The client device of claim 1 wherein the hash used for authentication of the user is n bits, the partial hash is k bits of the hash used for authentication of the user, and k is less than n.

11. The client device of claim 10 wherein the partial hash is the first k bits of the original hash.

12. The client device of claim 1 further operable to, based on the response from the proof of knowledge server based on the calculated hash for the sequence of the one or more input actions, permit access to the user.

13. A proof of knowledge server comprising:

one or more processors; and

memory containing instructions executable by the one or more processors whereby the server computer is operable to;

send a communication to a client device containing a partial hash where the partial hash is a value derived from an original hash of one or more original input actions used to authenticate a user;

receive a communication from a client device containing a calculated hash of one or more input actions; and

send a response based on the calculated hash for the sequence of the one or more input actions.

14. The proof of knowledge server of claim 13 wherein sending a response based on the hash for the sequence of the one or more input actions comprises:

determine if the hash received from the client device and the original hash of the one or more original input actions are the same;

if the hash received from the client device and the original hash are the same, send a communication to the client device, wherein the communication contains an indication that the user at the client device is authenticated; and

if the hash received from the client device and the original hash are not the same, send a communication to the client device, wherein the communication contains an indication that the user at the client device is not authenticated.

15. The proof of knowledge server of claim 13 wherein the original hash is n bits, the partial hash is k bits of the original hash, and k is less than n.

16. The client device of claim 15 wherein the partial hash is the first k bits of the original hash.