Secure control of security mode
View Patent ↗A system to change security levels is used to change the level of security used in a secured processing system. The system uses a status indicator to designate the security level being implemented. The security level can be upgraded to allow a higher level of security to be implemented with relative ease. However, in order to change from a higher level of security to a lower level of security, an authorization code is utilized to confirm that the change in security is authorized.
1. A method of providing varying levels of security in a data processing system, the method comprising:
receiving information from an outside source;
retrieving a first indicator form the received information that instructs the system to operate at a higher level of security;
receiving further information from said outside source;
retrieving a separate second indicator from said further information received from said outside source, the second indicator for instructing the system to operate at a lower level of security than the higher level of security instructed by the first indicator;
receiving an encrypted message that authorizes the system to operate at the lower level of security;
authenticating the encrypted message; and
preventing operation at the lower level of security until a decrease in security levels is indicated by said second indicator and the encrypted message; while continuing operation of said processing system at the higher level of security.
2. The method of claim 1 wherein the encrypted message comprises a Decreased-Security-Authorization-Code.
3. The method of claim 2 wherein said Decreased-Security-Authorization-Code authorizes a decrease in encryption/decryption levels.
4. The method of claim 2 wherein said Decreased-Security-Authorization-Code authorizes a decrease in authentication level.
5. The method of claim 2 wherein said Decreased-Security-Authorization-Code authorizes a decrease in authentication level and a decrease in encryption/decryption levels.
6. The method of claim 2 wherein said encrypted message further comprises a key for use in a decryption algorithm.
7. The method of claim 6 wherein said system stores a master key to decrypt messages comprising new decryption key values and further comprising:
using said master key stored at said system to decrypt said encrypted message.
8. The method of claim 1 and further comprising:
establishing a Security-Level-Status-Indicator at said system to indicate a level of security that is being implemented by the system.
9. The method of claim 8 wherein said Security-Level-Status-Indicator indicates a level of encryption/decryption that is being implemented by the system.
10. The method of claim 8 wherein said Security-Level-Status-Indicator indicates a level of authentication that is being implemented by the system.
11. The method of claim 8 wherein said Security-Level-Status-Indicator indicates a level of authentication and a level encryption/decryption that is being implemented by the system.
12. The method of claim 8 and further comprising:
configuring said Security-Level-Status-Indicator to indicate more than two security levels so as to allow said system to utilize more than two security levels.
13. The method of claim 1 and further comprising:
utilizing a cable head-end as said outside source; and
utilizing a set-top box in order to retrieve the first and second indicators from the information received from the cable head-end.
14. The method of claim 2 and further comprising using a Key Management Message to convey said Decreased Security Authorization Code.
15. The method of claim 14 wherein delivery of said Key Management Message is authenticated.
16. The method of claim 14 wherein delivery of said Key Management Message is protected against a replay attack.
17. The method of claim 14 wherein delivery of said Key Management Message is authenticated and protected against a replay attack.
18. The method of claim 1 wherein a lower level of security is non-public Key mode, wherein a higher level of security is a public Key mode, the method further comprising:
continuing operation of the system in the public Key mode until an encrypted predefined message is received by the system from the outside source.
19. The method of claim 18 wherein said system stores a master key to decrypt messages comprising new decryption key values and further comprising:
using said master key stored at said system to decrypt said encrypted message.