Method for programming on-chip non-volatile memory in a secure processor, and a device so programmed

• US 20080114984A1
• Filed: 11/16/2006
• Published: 05/15/2008
• Est. Priority Date: 11/09/2006
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd. (Samsung Group)
• Original Assignee: Broadon Communications Corp. (Acer, Inc.)
• Inventors: Srinivasan, Pramila, Princen, John
• Granted Patent: US 7,613,915 B2
• Time in Patent Office: Days
• US Class Current: 713/175
• CPC Class Codes: G06F 21/33 using certificates
• CPC Class Codes: G06F 21/71 to assure secure computing or processing of information
• CPC Class Codes: G06F 21/72 in cryptographic circuits
• CPC Class Codes: G06F 21/73 by creating or determining hardware identification, e.g. serial numbers
• CPC Class Codes: H04L 2209/603 Digital right managament [DRM]
• CPC Class Codes: H04L 9/0869 involving random numbers or seeds
• CPC Class Codes: H04L 9/3066 involving algebraic varieties, e.g. elliptic or hyper-elliptic curves
• CPC Class Codes: H04L 9/3213 using tickets or tokens, e.g. Kerberos network architectures or network communication protocols for entities authentication using tickets in a packet data network H04L63/0807
• CPC Class Codes: H04L 9/3263 involving certificates, e.g. public key certificate [PKC] or attribute certificate [AC]; Public key infrastructure [PKI] arrangements network architectures or network communication protocols for supporting authentication of entities using certificates in a packet data network H04L63/0823

Abstract

An improved secure programming technique involves reducing the size of bits programmed in on-chip secret non-volatile memory, at the same time enabling the typical secure applications supported by secure devices. A technique for secure programming involves de-coupling chip manufacture from the later process of connecting to ticket servers to obtain tickets. A method according to the technique may involve sending a (manufacturing) server signed certificate from the device prior to any communication to receive tickets. A device according to the technique may include chip-internal non-volatile memory to store the certificate along with the private key, in the manufacturing process.

Claims

1. A device comprising:

on-chip non-volatile (NV) memory including;

a device ID;

a private key;

an issuer ID;

a first signature;

a certificate generating module coupled to the non-volatile memory configured to;

read the device ID, private key, issuer ID, and first signature from the NV memory;

compute a public key as a function of the private key;

construct a device certificate as a function of the device ID, issuer ID, public key, and first signature;

an interface coupled to the certificate generating module, wherein, in operation, a request for the device certificate is received on the interface, the certificate generating module constructs the device certificate, and the device certificate is sent via the interface in response to the request.

2. The device of claim 1, wherein the certificate generating module is further configured to:

compute the public key as a function of the private key and common parameters;

construct the device certificate as a function of the device ID, issuer ID, public key, first signature, and the common parameters.

3. The device of claim 1, wherein, the device is further configured to compute a second signature as a function of a random number and the private key, wherein the interface receives the random number, and the second signature and random number are sent via the interface in response to the request, along with the device certificate.

4. The device of claim 3, wherein the device is further configured to:

create a temporary key pair having two keys, a temporary public key and a temporary private key, using a number generator;

create an application certificate by signing data including the temporary public key, using a stored private key;

using the temporary private key to compute the second signature as a function of a random number.

5. The device of claim 4, wherein the application certificate is sent to the server, along with the second signature, random number, and the device certificate.

6. The device of claim 1, wherein, the device is further configured to create temporary key pairs for applications.

7. The device of claim 1, wherein the non-chip NV read-only memory (ROM) includes a secret seed random number.

8. The device of claim 1, wherein the certificate generating module is further configured to compute a public key as a function of the private key using an elliptic curve based algorithm.

9. A server comprising:

a number generator;

a certificate request module;

a certificate verification module;

an interface, coupled to the number generator, the certificate request module, and the certificate verification module,

wherein, in operation

the number generator generates a first number,

the certificate request module generates a request for a device certificate, the first number and the request for a device certificate are sent via the interface, a response that includes a second number, a second signature that is generated using the second number, and a device certificate are received at the interface, and the certificate verification module validates the device certificate and the second signature, and verifies that the first number and the second number match.

10. The server of claim 9, wherein the interface receives a signature and the certificate validation module validates the signature using the device certificate.

11. The server of claim 9, wherein the number generator is a pseudo-random number generator.

12. The server of claim 9, wherein the number generator is a true random number generator.

13. The server of claim 9, wherein, in operation, the certificate verification module validates the device certificate using a trusted certificate chain.

14. The server of claim 9, further comprising a certificate database, wherein the device certificate is imported to the certificate database if validated by the certificate verification module.

15. A device comprising:

on-chip non-volatile (NV) memory including;

a secret seed random number;

on-chip writable memory including;

a stored sequence number;

a means for initializing a state variable to an initial value;

a means for computing a key as a function of the secret seed random number and the sequence number;

a means for incrementing the sequence number;

a means for storing the incremented sequence number;

a means for generating a random number as a function of a key and the state variable;

a means for incrementing the state variable.

16. The device of claim 15 further comprising a means for generating a random number using the key and incremented state variable.

17. The device of claim 15, wherein the function used for generating the key and for generating the random number is selected from the group consisting of cryptographically strong encryption, decryption, and hash functions.

18. A method comprising:

obtaining a device ID of a device;

providing a number to use as a small-signature private key;

computing a public key from the small-signature private key using common parameters;

using a fixed certificate structure to compute a signature with a small-signature algorithm;

programming device ID, small-signature private key, issuer ID, and signature into non-volatile (NV) memory of the device.

19. The method of claim 18, further comprising programming a secret seed random number in read-only memory (ROM) of the device.

20. The method of claim 18, wherein the small signature is computed using an elliptic curve digital signature algorithm (DSA).

21. The method of claim 18, further comprising:

receiving a request for a device certificate from a calling application;

reading the device ID, small-signature private key, issuer ID, and signature from the NV memory of the device;

computing the public key as a function of the small-signature private key and common parameters;

constructing a device certificate as a function of the device ID, issuer ID, public key, signature, and common parameters;

providing the device certificate to the calling application.

22. A device, comprising:

on-chip non-volatile (NV) memory for storing a private key;

a secure processor;

a secure on-chip memory having one or more modules stored thereon, including a security kernel having an authenticated security API;

wherein, in operation, the security kernel uses the private key to generate a device certificate using a supplied signature.

23. The device of claim 22, further comprising:

on-chip read-only memory (ROM) for storing a programmed secret seed;

the on-chip NV memory for storing rewritable state;

wherein, in operation, the security kernel uses the programmed secret seed and rewritable state to generate secret random numbers for key material.

24. A method comprising:

initializing a state variable to an initial value;

computing a key as a function of a secret seed random number and a sequence number;

incrementing the sequence number;

generating a random number as a function of a key and the state variable;

incrementing the state variable;

generating a random number using the key and incremented state variable.