METHOD OF AUTHENTICATING PRINT MEDIUM USING PRINTING MOBILE DEVICE

• US 20080320309A1
• Filed: 09/08/2008
• Published: 12/25/2008
• Est. Priority Date: 05/09/2005
• Status: Active Grant

• Current Assignee: Silverbrook Research Pty Limited
• Original Assignee: Silverbrook Research Pty Limited
• Inventors: Silverbrook, Kia, Lapstun, Paul
• Granted Patent: US 8,020,002 B2
• Time in Patent Office: Days
• US Class Current: 713/176
• CPC Class Codes: H04L 2209/20 Manipulating the length of blocks of bits, e.g. padding or block truncation
• CPC Class Codes: H04L 2209/56 Financial cryptography, e.g. electronic payment or e-cash
• CPC Class Codes: H04L 2209/805 Lightweight hardware, e.g. radio-frequency identification [RFID] or sensor
• CPC Class Codes: H04L 9/12 Transmitting and receiving encryption devices synchronised or initially set up in a particular manner
• CPC Class Codes: H04L 9/3247 involving digital signatures

Abstract

A method of using a mobile device to authenticate a print medium offline before completing printing onto the print medium, the mobile device including processing means, a printhead and a sensor, the print medium comprising a laminar substrate, the method comprising the steps of: using the sensor to sense coded data provided on a surface of the substrate; using the processing means: determining, from the sensed coded data: an identity of the print medium; and at least part of a signature, the signature being a digital signature of at least part of the identity; determining, using the at least part of the signature, a determined signature; generating, using the determined signature and a public key stored in the mobile device, a generated identity; comparing the identity to the generated identity; and authenticating the print medium using the results of the comparison; and in the event the authentication step is successful, using the printhead to print onto the print medium.

Claims

1. A method of authenticating a print medium to allow printing thereon by a printhead of a mobile device, the method comprising using the mobile device to:

sense coded data on the print medium to determine an identity of the print medium, a plurality of parts of a digital signature of the identity and part identifiers which each identify a respective signature part encoded by the coded data;

determine, using the determined signature parts and part identifiers, a determined signature;

generate, using the determined signature and a public key stored in the mobile device, a generated identity; and

compare the determined and generated identities to determine if the print medium is authentic.

2. A method according to claim 1, wherein the plurality of parts of the signature are indicative of an entire signature.

3. A method according to claim 1, wherein the digital signature includes padding, the method comprising using the mobile device to determine, using the determined identity, the padding, and to generate, using the public key and the determined padding and signature, the generated identity.

4. A method according to claim 3, wherein the mobile device includes a transmitter and a receiver, the method comprising:

using the transmitter to send a first message to a remote computer system, the first message being indicative of the identity; and

using the receiver to receive a second message from the remote computer system, the second message including data indicative of the padding.

5. A method according to claim 1, wherein the digital signature includes at least one of:

a random number associated with the identity;

a keyed hash of at least the identity;

a keyed hash of at least the identity produced using a private key, and verifiable using the public key;

cipher-text produced by encrypting at least the identity;

cipher-text produced by encrypting at least the identity and a random number; and

cipher-text produced using a private key, and verifiable using the public key.

6. A method according to claim 1, wherein the print medium includes an orientation indicator, the method comprising using the mobile device to:

sense the orientation indicator prior to sensing the coded data; and

prevent printing in the event the print medium is inserted incorrectly in a print path of the mobile device.