System, device, and method of selectively allowing a host processor to access host-executable code

1. A host apparatus comprising:

a host processor; and

a memory module, comprising:

a memory to maintain a host-executable code to be executed by said host processor; and

a security module comprising logic to authenticate said host-executable code and to selectively allow said host processor to access said host-executable code based on an authenticity of said host-executable code;

wherein said host-executable code is divided into at least two parts,

wherein said security module is adapted to verify the authenticity of said host-executable code,

wherein said host processor is adapted to execute the code of a first part of said at least two parts while the portion of said memory that is used to store said first part of host-executable code is protected by said security module from having its contents modified by said host processor at least during the period at which said security module verifies said first part of host-executable code,

wherein said verification is performable during a time period that is at least partially overlapping the time period at which said host processor executes said first part of said host executable code; and

wherein said code in said first part includes one or more instructions that disable said host processor from executing code of other parts in said memory but the said first part until said security module signals that all said host-executable code is authentic.

2. The host apparatus of claim 1 , wherein said security module is incorporated with said memory module on the same chipset.

3. The host apparatus of claim 1 , wherein said security module limits access of said host processor to contents of said memory if said host-executable code is found by said security module to be non-authentic.

4. The host apparatus of claim 1 , wherein:

said host-executable code contains update code that, when executed by said host processor, causes said host processor to change said host-executable code on said memory module;

said first part of said host-executable code contains one or more instructions that, when executed by said host processor, and when receiving an update signal from said security module, cause said host processor to execute said update code; and

said secure module indicates verified authenticity of said update code, by said update signal, to said host processor.

5. The apparatus of claim 1 , wherein only the first of said parts of host-executable code contains any instructions.

6. The apparatus of claim 5 wherein said security module is incorporated with said memory module on the same chipset.

7. The apparatus of claim 5 wherein said security module limits access of said host processor to contents of said memory, if said host-executable code is found by said security module to be non-authentic.

8. A host apparatus comprising:

a host processor;

a memory module comprising a memory to maintain a host-executable code to be executed by said host processor; and

a security module comprising logic to authenticate said host-executable code and to selectively allow said host processor to access said host-executable code based on an authenticity of said host-executable code,

wherein:

said host-executable code is adapted to contain update code that, when executed by said host processor, causes said host processor to change said host-executable code on said memory module, said update code is different from said host-executable code;

said security module to verify the authenticity of said host-executable code;

said security module to verify the authenticity of said update code;

said security module is adapted to send data to said host processor during the process of said verification, that causes said host processor to wait until said verification processes complete; and

if host-executable code was determined by said verification process to be non-authentic and said update code was determined by said verification process to be authentic, then said security module sends data to said host processor, wherein said data causes said host processor to execute said update code.

9. A method of selectively allowing a host processor to access a host-executable code, said method comprising:

storing host-executable code on a memory module;

allowing a security module to selectively allow a host processor to access said host-executable code, comprising:

dividing said host-executable code into at least two parts;

allowing said security module to verify the authenticity of said host-executable code;

allowing said security module to restrict access of said host processor to said first part of host-executable code to read-only access while authenticity of said first part of host-executable code is being verified by said security module;

allowing said host processor to execute at least a portion of the code of said first part during a time period that is at least partially overlapping the time period at which said security module carries out said verification; and

allowing said first part of host-executable code to contain one or more instructions that, when executed by said host processor, cause said host processor to not execute code of other parts but the said first part before said security module signals that all said host-executable code is authentic.

10. The method of claim 9 wherein said security module limits access of said host processor to contents of said memory, if said host-executable code is found by said security module to be non-authentic.

11. The method of claim 9 further comprising:

allowing host-executable code to contain update code that, when executed by said host processor, causes said host processor to change said host-executable code on said memory module;

allowing said first part of said host-executable code to contain one or more instructions that, when executed by said host processor and when an update signal from said security module is received, cause said host processor to execute said update code; and

allowing said secure module to indicate the verified authenticity of said update code, using said update signal, to said host processor.

12. The method of claim 9 , wherein only the first of said parts of host-executable code contains any instructions.

13. The method of claim 12 wherein said security module causes limitation to the functionality of said host processor, by limiting access of said host processor to contents of said memory if said host-executable code is found by said security module to be non-authentic.

14. A method of selectively allowing a host processor to access a host-executable code, said method comprising:

storing host-executable code on a memory module;

storing update code that, when executed by said host processor, causes said host processor to change said host-executable code on said memory module said update code is different from said host-executable code;

allowing said security module to selectively allow said host processor to access said host-executable code, comprising:

allowing said security module to verify the authenticity of said host-executable code;

allowing said security module to verify the authenticity of said update code;

allowing said security module to send data to said host processor, during said verification process wherein said data causing said host processor to wait until said verification process completes; and

allowing said security module to carry out a decision process once verification process completes,

wherein:

if said host-executable code was found by said verification process to be non-authentic and said update code was found by said verification process to be authentic, then said decision process results in allowing said security module to send data to said host processor wherein said data causes said host processor to execute said update code; and

if said host-executable code was found by said verification process to be authentic, then said decision process results in allowing said host processor to execute said host-executable code.