AUTHENTICATION PROCESSING APPARATUS AND AUTHENTICATION PROCESSING METHOD

Abstract

The authentication processing apparatus according to the present invention includes: an authentication unit having a circuit that performs authentication phases included in processing for authenticating an external device; a command holding unit which holds a first command that indicates whether or not to perform each of the authentication phases; and an authentication control unit which causes the authentication unit to perform an authentication phase that is indicated by the first command as an authentication phase which is to be performed.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects, advantages and features of the invention will become apparent from the following description thereof taken in conjunction with the accompanying drawings that illustrate a specific embodiment of the invention. In the

DRAWINGS

FIG. 1 is a block diagram which shows the structure of a conventional HDMI communication system;

FIG. 2 is a block diagram which shows the structure of an HDMI communication system in an embodiment of the present invention;

FIG. 3 is a diagram which shows an example of the structure of a command register;

FIG. 4 is a diagram which shows an example of the structure of a timer register;

FIG. 5 is a diagram which shows an example of signals in DDC communication;

FIG. 6 is a flowchart which shows a flow of authentication processing in the present embodiment;

FIG. 7 is a flowchart which shows a flow of the first authentication process;

FIG. 8 is a flowchart which shows a flow of the second authentication process;

FIG. 9 is a flowchart which shows a flow of the third authentication process;

FIG. 10 is a flowchart which shows a flow of processing performed in each authentication phase; and

FIG. 11 is a flowchart which shows a flow of judgment processing.

Claims

1. An authentication processing apparatus comprising: an authentication unit having a circuit that performs authentication phases included in processing for authenticating an external device;a command holding unit operable to hold a first command that indicates whether or not to perform each of the authentication phases; andan authentication control unit operable to cause said authentication unit to perform an authentication phase that is indicated by the first command as an authentication phase which is to be performed.

2. The authentication processing apparatus according to claim 1, wherein the first command includes a plurality of bits, each corresponding to one of the authentication phases,each of the bits included in the first command indicates whether or not to perform the corresponding authentication phase, andsaid authentication control unit is operable to cause said authentication unit to perform the authentication phase that is indicated, by the corresponding bit included in the first command held in said command holding unit, as an authentication phase which is to be performed.

3. The authentication processing apparatus according to claim 1, further comprising a data holding unit operable to hold, for a subsequent authentication phase, authentication data generated in an authentication phase performed by said authentication unit.

4. The authentication processing apparatus according to claim 3, wherein said authentication unit is operable to read, from said data holding unit, authentication data generated in a previous authentication phase, and to perform an authentication phase using the authentication data.

5. The authentication processing apparatus according to claim 4, further comprising a central processing unit (CPU) operable to perform software processing on an authentication phase that is indicated, by the first command held in said command holding unit, as an authentication phase which is not to be performed,wherein said data holding unit is operable to hold, for a subsequent authentication phase, authentication data generated in the authentication phase performed by said CPU, andsaid CPU is operable to read, from said data holding unit, authentication data generated in a previous authentication phase, and to perform software processing on an authentication phase using the authentication data.

6. The authentication processing apparatus according to claim 1, further comprising a display data channel (DDC) communication unit operable to perform DDC communication with the external device,wherein said authentication unit is operable to send and receive data to and from the external device via said DDC communication unit.

7. The authentication processing apparatus according to claim 6, wherein said command holding unit is operable to hold a second command that indicates whether or not to reset a DDC communication line with the external device, andsaid DDC communication unit includes a reset generation unit operable to generate a signal for resetting the DDC communication line based on the second command held in said command holding unit.

8. The authentication processing apparatus according to claim 1, wherein said command holding unit is operable to hold a third command that indicates whether or not to insert delay time into between the respective authentication phases,said authentication processing apparatus further comprisesa timer unit operable to count the delay time, andsaid authentication control unit is operable to insert the delay time counted by said timer unit into between authentication phases indicated by the third command as authentication phases between which delay time is to be inserted.

9. The authentication processing apparatus according to claim 1, further comprising a central processing unit (CPU) operable to perform software processing on an authentication phase that is indicated, by the first command held in said command holding unit, as an authentication phase which is not to be performed.

10. The authentication processing apparatus according to claim 1, further comprising: a storage unit operable to store device information that identifies the external device and the first command that corresponds to the external device;a device information acquisition unit operable to acquire the device information of the external device to be authenticated; anda device information control unit operable to read, from said storage unit, the first command that corresponds to the device information acquired by said device information acquisition unit, and to write the first command into said command holding unit.

11. The authentication processing apparatus according to claim 1, wherein the processing for authenticating the external device is processing which is compliant with the high-bandwidth digital content protection (HDCP) standard, andsaid authentication unit includes:a first authentication unit having a circuit that performs an authentication phase included in a first authentication process which is compliant with the HDCP standard;a second authentication having a circuit that performs an authentication phase included in a second authentication process which is compliant with the HDCP standard; anda third authentication unit having a circuit that performs an authentication phase included in a third authentication process which is compliant with the HDCP standard.

12. An authentication processing method used in an authentication processing apparatus including an authentication unit having a circuit that performs authentication phases included in processing for authenticating an external device and a command holding unit operable to hold a first command that indicates whether or not to perform each of the authentication phases, said method comprising: judging, based on the first command, whether or not to perform each of the authentication phases; andcausing the authentication unit to perform an authentication phase that is judged in said judging as an authentication phase which is to be performed.