Secure client authentication based on conditional provisioning of code signature

1. A memory subsystem, comprising:

a memory interface for accessing a non-volatile memory (NVM);

a host interface for communicating with a host; and

a microprocessor, configured to:

calculate a signature over program code that is used by the host and is stored in the NVM;

upon detecting a power-up of the host, verify whether first read commands issued by the host following the power-up are directed to addresses in accordance with predefined addresses expected for a genuine boot code; and

only if the first read commands were verified to be directed to addresses of the genuine boot code, provide the signature to the host for authentication to a remote server.

2. The memory subsystem according to claim 1 , wherein the processor is configured to store the signature in a volatile register, and to clear the volatile register in response to detecting a read command addressed to an address outside a range of the genuine boot code.

3. The memory subsystem according to claim 1 , wherein the processor is further configured to verify that memory accesses after the first read commands issued by the host following the power-up are directed to a range of memory addresses considered legitimate for after boot access, wherein the range of memory addresses considered legitimate for after boot access is larger than a range including the predefined addresses expected for a genuine boot code.

4. A secure client device, comprising:

a non-volatile memory (NVM);

a host; and

a memory subsystem, configured to:

access the NVM for the host;

calculate a signature over program code that is used by the host and is stored in the NVM;

upon detecting a power-up of the host, verify whether first read commands issued by the host following the power-up are directed to addresses in accordance with predefined addresses expected for a genuine boot code; and

only if the first read commands were verified to be directed to addresses of the genuine boot code, provide the signature to the host for authentication to a remote server.

5. The secure client device according to claim 4 , wherein the memory subsystem is configured to store the signature in a volatile register, and to clear the volatile register in response to detecting a read command addressed to an address outside a range of the genuine boot code.

6. The secure client device according to claim 4 , wherein the memory subsystem is further configured to verify that memory accesses after the first read commands issued by the host following the power-up are directed to a range of memory addresses considered legitimate for after boot access, wherein the range of memory addresses considered legitimate for after boot access is larger than a range including the predefined addresses expected for a genuine boot code.

7. A method, comprising:

calculating a signature over program code that is used by a host and is stored in a non-volatile memory (NVM);

upon detecting a power-up of the host, verifying whether first read commands issued by the host following the power-up are directed to addresses in accordance with predefined addresses expected for a genuine boot code; and

only if the first read commands were verified to be directed to addresses of the genuine boot code, providing the signature to the host for authentication to a remote server.

8. The method according to claim 7 , and comprising storing the signature in a volatile register, and clearing the volatile register in response to detecting a read command addressed to an address outside a range of the genuine boot code.

9. The method according to claim 7 , and comprising verifying that memory accesses after the first read commands issued by the host following the power-up are directed to a range of memory addresses considered legitimate for after boot access, wherein the range of memory addresses considered legitimate for after boot access is larger than a range including the predefined addresses expected for a genuine boot code.