SYSTEM AND METHOD FOR USER AUTHENTICATION WITH EXPOSED AND HIDDEN KEYS

• US 20080240447A1
• Filed: 03/26/2008
• Published: 10/02/2008
• Est. Priority Date: 03/26/2007
• Status: Active Grant

• Current Assignee: Xuebin Jiang, Yunzhou Zhu
• Original Assignee: Xuebin Jiang, Yunzhou Zhu
• Inventors: ZHU, Yunzhou, JIANG, Xuebin
• Granted Patent: US 8,132,020 B2
• Time in Patent Office: Days
• US Class Current: 380/279
• CPC Class Codes: H04L 2209/603 Digital right managament [DRM]
• CPC Class Codes: H04L 2209/80 Wireless network architectures or network communication protocols for wireless network security H04W12/00
• CPC Class Codes: H04L 2463/081 applying self-generating credentials, e.g. instead of receiving credentials from an authority or from another peer, the credentials are generated at the entity itself cryptographic mechanisms or cryptographic arrangements for generation of secret information including derivation or calculation of cryptographic keys or passwords H04L9/0861
• CPC Class Codes: H04L 63/0853 using an additional device, e.g. smartcard, SIM or a different communication terminal cryptographic mechanisms or cryptographic arrangements for entity authentication involving additional secure or trusted devices H04L9/3234
• CPC Class Codes: H04L 9/3234 involving additional secure or trusted devices, e.g. TPM, smartcard, USB or software token network architectures or network communication protocols for supporting authentication of entities using an additional device in a packet data network H04L63/0853
• CPC Class Codes: H04L 9/3271 using challenge-response

Abstract

The present invention relates to a system and method for digitally authenticating users both online and offline. In one embodiment, a hardware token assigned by a trusted token provider to the user is employed to ensure the identity of the user. In the online authentication, the token is adapted for generating an exposed key EK and a hidden key HK based on a noise code NC and a time code TC of the token, a space code SC of a service server, and an owner code OC of the user. A login session is initialized by entering a user identifier at the service server and the generated EK from a computing device. The service server computes an expose key CEK and a hidden key CHK based one an authentication license generated by the token provider. The service server authenticates the user if the CEK is same as the EK, and sends a response message encrypted the CHK to the computing device. Then, the user provides the HK to the computing device to decrypt the encrypted response message so as to access his/her account. In the offline authentication, the token is adapted for generating a license exposed key LEK used to render the encrypted digital content on an offline compliant device. The compliant device authenticates the user if a license exposed key computed by the compliant device based on a content license of which the user bought is same as LEK, so as to render the protected digital content after authentication.

Claims

1. A method for digitally authenticating a user over a network system having at least one service server, at least one client device and a token provider communicable with one another through the internet, wherein the user has an account established with an account identifier (UserID) in the at least one service server, a hardware token assigned by the token provider, and an owner code (OC) known only by the user and the token provider, wherein the at least one service server has a uniquely global identifier (SC) and an authentication license (AL) associated with the identification information of the at least one service server, the hardware token and the user, wherein the AL is provided by the token provider and stored in the at least one service server, wherein the SC and the OC are stored in a database of the token provider, and wherein the hardware token is communicable with the at least one client device and the database of the token provider, comprising the steps of:

a. entering the SC and the OC into the token by the user;

b. generating a first exposed key (EK) and a first hidden key (HK) by the token, wherein each of the EK and the HK is associated with at least the and the OC, and a time code (TC) and a noise code (NC) of the token, wherein the TC is the current time of the token when the EK and the HK are generated, and the NC is a built-in secret string of the token;

c. initializing a user login session of the at least one service server from the at least one client device by the user to enter the UserID and the generated EK thereinto, wherein the UserID and the generated EK are transmitted to the at least one service server through the internet;

d. computing a second exposed key (CEK) and a second hidden key (CHK) by the at least one service server based on the AL provided by the token provider;

e. authenticating the user by at the at least one service server when the CEK is same as the EK;

f. sending a response message to the at least one client device by the at least one service server, wherein the response message is encrypted with the CHK; and

g. decrypting the response message received from the at least one service server at the at least one client device with the HK.

2. The method of claim 1, wherein the hardware token comprises at least:

a. a tamper-proof and irreversible time clock with a value of a time code (TC) for generating dynamic keys in any second;

b. a stored tamper-proof and non-volatile noise code (NC) for securing hashed data;

c. a stored tamper-proof and non-volatile license noise code (LNC);

d. means for receiving and displaying the space code (SC) of the at least one service server;

e. means for receiving the owner code (OC) of the user to be authorized;

f. means for generating the first exposed key (EK);

g. means for generating the first hidden key (HK);

h. means for computing a license exposed key (LEK);

i. means for transmitting the HK or LEK to a selected device wirelessly or non-wirelessly; and

j. means for storing an OC history list OCHL of a predefined number of the distinct received OCs ordered by their occurring frequencies so that the key computing time is increased exponentially with the order index of the newly received OC.

3. The method of claim 2, wherein the step of generating the first exposed key (EK) by the token comprises the steps of:

a. computing a first account-lockout-proof key (AK) by hashing a combination of the NC of the token and the SC of the at least one service server using a first hash function H1;

b. computing a first verifier key (VK) by hashing a combination of the NC, the SC and the OC using a second hash function H2;

c. computing a timed account-lockout-proof key (TAK) by hashing a combination of the TC and the AK using a third hash function H3;

d. computing a timed verifier key (TVK) by hashing a combination of the TC and the VK using a fourth hash function H4; and

e. generating the first exposed key (EK) by concatenating the TAK and the TVK.

4. The method of claim 3, wherein the authentication license (AL) is generated by the token provider by:

a. computing a second account-lockout-proof key (CAK) by hashing a combination of the NC of the token and the SC of the at least one service server using the first hash function H1;

b. computing a second verifier key (CVK) by hashing a combination of the NC, the SC and the OC using the second hash function H2; and

c. generating the AL by grouping the CAK and the CVK,

wherein the NC of the token, the SC of the at least one service server and the OC of the user are stored in the database of the token provider.

5. The method of claim 4, wherein the step of authenticating the user by at the at least one service server comprises the steps of:

a. finding a synchronous time ST within the range of (CT−

p, CT+p), wherein the CT is the current time of the at least one service server, and p is a time tolerance, such that the value of hashing a combination of the ST and the CAK of the authentication license (AL) using the third hashing function H3 is same as the TAK contained in the received EK;

b. authenticating the user by sending the response message to the at least one client device if the ST exists in the range of (CT−

p, CT+p) and the value of hashing a combination of the ST and the CVK of the authentication license (AL) using the fourth hash function H4 is same as the TVK contained in the received EK; and

c. storing the ST as a new used timestamp (UT) in the at least one service server if the user is authenticated.

6. The method of claim 5, further comprising the step of rejecting the user if the ST is out of the range of (CT−

p, CT+p).

7. The method of claim 5, further comprising the step of rejecting the user if the ST is in the range of (CT−

p, CT+p) and the value of hashing the combination of the ST and the CVK of the authentication license (AL) using the fourth hash function H4 is different from the TVK contained in the received EK.

8. The method of claim 5, further comprising the step of rejecting the user if the found synchronous time ST is less than or same as the stored used timestamp UT, thereby ensuring each EK being used for authentication only once.

9. The method of claim 5, further comprising verifying an account-lockout-proof key segment of the EK on the at least one service server during the login session so as to prevent account lockout attacks, wherein the verifying step comprises the steps of:

a. setting a failure number (FN) as 0 for the account if the user is authenticated;

b. blocking the account if the failure number FN of the account exceeds a pre-defined number; and

c. increasing the FN by 1 only if the a value of hashing a combination of the ST and the CAK of the authentication license (AL) using the third hashing function H3 is same as the TAK contained in the received EK, while the value of hashing a combination of the ST and the CVK of the authentication license (AL) using the fourth hash function H4 is different from the TVK contained in the received EK,

wherein the FN is initially set as 0.

10. The method of claim 5, wherein the first hidden key (HK) is generated by the token by hashing a combinations of the AK, the VK and the TC using a fifth hash function H5 at the time when the EK is generated in the token, and wherein the second hidden key (CHK) is computed by the at least one service server by hashing a combinations of the CAK, the CVK and the ST with the fifth hash function H5, by the at least one service server after the ST is found.

11. The method of claim 1, wherein the step of decrypting the response message received from the at least one service server at the at least one client device by the HK comprises the steps of:

a. transmitting the HK from the token to the at least one client device wirelessly or non-wirelessly;

b. decrypting the received response message by the HK with an algorithm that is utilized to encrypt the response message by the CHK at the at least one service server; and

c. rendering the decrypted response message on the at least one client device.

12. The method of claim 1, further comprising the step of authenticating the user by the at least one service server over the internet with a hardware token owned by a delegate of the user, wherein the authenticating step comprises the steps of:

a. registering a delegate identifier (DelegateID) of the delegate at the token provider by the user with confirmation of the delegate, wherein the delegate has a hardware token assigned by the token provider;

b. sending a new authentication license associated with the user to the at least one service server by the token provider, wherein the new authentication license includes an additional mixture user-delegate authentication sub-license (ASL); and

c. authenticating the user with the hardware token of the user'"'"'s delegate, and the mixture user-delegate authentication sub-license ASL.

13. The method of claim 12, wherein the mixture user-delegate authentication sub-license ASL for the user is generated by the token provider with the steps of:

a. computing an account-lockout-proof key (AK) by hashing a combination of the NC of the token of the delegate and the SC, using the first hash function H1;

b. computing a verifier key (VK) by hashing a combination of the NC of the token of the delegate, the SC and the OC of the user using the second hash function H2; and

c. generating the mixture user-delegate authentication sub-license ASL by grouping AK and VK.

14. The method of claim 12, wherein the step of authenticating the user with the hardware token of the delegate of the user comprises the steps of:

a. providing the delegate identifier (DelegateID) by the user during the login session;

b. providing the EK and the HK by the user with the hardware token of the delegate using the user'"'"'s owner code OC and the space code SC of the at least one service server;

c. authenticating the user by the at least one service server if the exposed key, hashed on the found ST and the information included in the mixture user-delegate authentication sub-license ASL with H3 and H4, matches the received EK;

d. using the HK, hashed on the found ST and the information included in the mixture user-delegate authentication sub-license ASL with H5, to encrypt a response message at the at least one service server; and

e. Using the HK, generated by the token of the delegate, to decrypt the received encrypted response message at the at least one client device.

15. Software stored on a computer readable medium for causing a network system to perform functions to authenticate a user over the network system, wherein the network system has at least one service server, at least one client device and a token provider communicable with one another through the internet, wherein the user has an account established with an account identifier (UserID) in the at least one service server, a hardware token assigned by the token provider, and an owner code (OC) known only by the user and the token provider, wherein the at least one service server has a uniquely global identifier (SC) and an authentication license (AL) associated with the identification information of the at least one service server, the hardware token and the user, wherein the AL is provided by the token provider and stored in the at least one service server, wherein the SC and the OC are stored in a database of the token provider, and wherein the hardware token is communicable with the at least one client device and the database of the token provider, the functions comprising:

a. entering the SC and the OC into the token by the user;

b. generating a first exposed key (EK) and a first hidden key (HK) by the token, wherein each of the EK and the HK is associated with at least the and the OC, and a time code (TC) and a noise code (NC) of the token, wherein the TC is the current time of the token when the EK and the HK are generated, and the NC is a built-in secret string of the token;

c. initializing a user login session of the at least one service server from the at least one client device by the user to enter the UserID and the generated EK thereinto, wherein the UserID and the generated EK are transmitted to the at least one service server through the internet;

d. computing a second exposed key (CEK) and a second hidden key (CHK) by the at least one service server based on the AL provided by the token provider;

e. authenticating the user by at the at least one service server when the CEK is same as the EK;

f. sending a response message to the at least one client device by at the at least one service server, wherein the response message is encrypted with the CHK; and

g. decrypting the response message received from the at least one service server at the at least one client device by the HK.

16. A method for authenticating a user to render a piece of protected digital content stored in a compliant device in an offline system with a content publisher, a compliant device, a service server and a token provider, wherein the compliant device has a core content token (CCT) installed therein, wherein the service server has a uniquely global identifier (SC) and are adapted for providing a content license (CL) of the piece of protected digital content, wherein the user has an account established with an account identifier (UserID) in the service server, a hardware token assigned by the token provider, and an owner code (OC) known only by the user and the token provider, wherein the SC and the OC are stored in a database of the token provider, comprising the steps of:

a. generating two pairs of RSA public and private keys (PU_FOR_PUBLISHER, PR_FOR_PUBLISHER) and (PU_FOR_TOKEN, PR_FOR_TOKEN) by a consortium joined by the content publisher, the compliant device manufacture, and the token provider such that

(i). the token provider is assigned the public key PU_FOR_TOKEN;

(ii). the content publishers is assigned with the same public key PU_FOR_PUBLISHER; and

(iii). private keys PR_FOR_PUBLISHER and PR_FOR_TOKEN are stored in the core content token CCT installed in the compliant device,

b. packaging the digital content as a piece of the protected digital content by the content publisher;

c. requesting the content license (CL) of the protected digital content by the user from the service server;

d. providing a license exposed key (LEK) by the user with the hardware token to the compliant device; and

e. authenticating the offline user by the compliant device for rendering the protected digital content based on the received LEK and the content license,

wherein the CCT is built by the consortium.

17. The method of claim 16, wherein the step of packaging the digital content by the publisher comprises the steps of:

a. generating a globally unique identifier, CONTENT_ID, for each piece of digital content;

b. encrypting the digital content by a symmetric encryption algorithm based on a random encryption key, CONTENT_KEY, to form a protected digital content, PROTECTED_CONTENT; and

c. distributing freely the protected digital content PROTECTED_CONTENT.

18. The method of claim 16, wherein the step of requesting the content license (CL) of the protected digital content by the user from the service server comprises the steps of:

a. logging in the service server by the user with the user identifier UserID and an exposed key EK generated by the token;

b. providing the desired CONTENT_ID and the required digital right by the user to the service server;

c. sending the collected data and request from the service server to the token provider;

d. generating a random dynamic license key DLK, with the same length of LNC of the user by the token provider;

e. computing a supplement license key SLK, by applying exclusive OR operation on the DLK and the LNC, by the token provider so that LNC is revealable by using exclusive OR on the DLK and the SLK;

f. sending the CONTENT_ID, the DLK, and the digital rights information from the token provider to a corresponding digital content publisher;

g. generating a random dynamic content key DCK, with the same length of CONTENT_KEY associated with the CONTENT_ID, by the digital content publisher;

h. computing a supplement content key SCK, by applying exclusive OR operation on the DCK and the CONTENT_KEY, by the digital content publisher so that CONTENT_KEY is revealable by using exclusive OR on the DCK and the SCK;

i. encrypting the CONTENT_ID, the SCK, the DLK and the digital rights information by the digital content publisher with public key PU_FOR_PUBLISHER to form the LICENSE_BODY;

j. sending the LICENSE_BODY and the DCK from the digital content publisher to the token provider;

k. encrypting the CONTENT_ID, the SLK and the DCK by the token provider with public key PU_FOR_TOKEN to form the LICENSE_HEADER;

l. packaging the LICENSE_HEADER and the LICENSE_BODY received from the token provider by the service server to form the content license CL; and

m. sending the content license CL from the service server to the user.

19. The method of claim 16, wherein the step of providing the license exposed key LEK by the user with the hardware token comprises the step of generating the license exposed key by the hardware token with a sixth hash function H6 on a combination of the license noise code LNC and the time code TC of the hardware token.

20. The method of claim 16, wherein the hardware core content token CCT installed in the compliant device comprises:

a. a tamper-proof and irreversible time clock having a device time code DTC;

b. means for storing tamper-proof and non-volatile private keys PR_FOR_TOKEN, PR_FOR_PUBLISHER;

c. means for receiving the license exposed key LEK provided by the user wired or wirelessly;

d. means for computing CONTENT_ID, CONTENT_KEY and LNC by decrypting the content license CL;

e. means for computing LEK based on LNC and a synchronous time ST; and

f. means for decrypting PROTECTED_CONTENT with key CONTENT_KEY;

21. The method of claim 20, wherein the CONTENT_KEY and the LNC are computed by the core content token CCT installed the compliant device by the steps of:

a. decrypting the LICENSE_HEADER with the stored private key PR_FOR_TOKEN by the core content token CCT to get the CONTENT_ID, the SLK and the DCK;

b. decrypting the LICENSE_BODY with the stored private key PR_FOR_PUBLISHER by the core content token CCT to get the CONTENT_ID, the SCK and the DLK;

c. rejecting the rendering request by the compliant device if the CONTENT_D decrypted from LIENSE_HEADER is substantially different from the CONTENT_ID decrypted from the LICENSE_BODY;

d. performing exclusive OR on DCK and SCK by the core content token CCT installed in the compliant device to form the CONTENT_KEY of the content; and

e. performing exclusive OR on the DLK and the SLK by the core content token CCT to form the LNC of the hardware token owned by the user.

22. The method of claim 21, wherein the step of authenticating the offline user by the compliant device for rendering the digital content comprises the steps of:

a. installing the content license CL into the compliant device by the user;

b. requesting the compliant device by the user to rendering the installed the protected digital content;

c. verifying the CONTENT_ID by the core content token CCT installed in the compliant device based on the installed content license;

d. providing the LEK by the user to the compliant device without entering the owner code OC and the space code SC into the hardware token;

e. finding a synchronous time ST within the range of (CT−

q, CT+q), wherein the CT is the current time of the core content CCT token, and q is a time tolerance, such that a value of hashing a combination of the LNC and the ST, using the sixth hash function H6 is same as the received LEK;

f. using a used timestamp UT to remove the possible multiple authentications for one LEK;

g. authenticating the user if the value of hashing a combination of the LNC and the ST, using the sixth hash function H6 is same as the received LEK;

h. decrypting the PROTECTED_CONTENT by the core content token CCT installed in the compliant device with the CONTENT_KEY; and

i. rendering the decrypted digital content by the compliant device based on the digital right embedded in the CL.

23. The method of claim 22, wherein the step of authenticating the offline user by the compliant device for rendering the digital content further comprises the step of rejecting the rendering request if the value of hashing a combination of the LNC and the ST, using the sixth hash function H6 is different from the received LEK.

24. The method of claim 20, wherein the step of authenticating the offline user by the compliant device for rendering the protected digital content comprises the steps of:

a. triggering the hardware token by the user to generate the license exposed key LEK;

b. emitting a requesting signal for rendering the protected digital content from the hardware token to the compliant device;

c. generating a random challenge number CHALLENGE by the CCT of the compliant device;

d. emitting a signal corresponding to the CHALLENGE from the compliant device;

e. receiving the signal corresponding to the CHALLENGE by the hardware token;

f. generating a challenged license exposed key CLEK=E(H(M(LNC∥

CHALLENGE, H(TC)))) by the hardware token, where ∥

is a concatenation operator;

g. receiving the CLEK by the CCT of the compliant device;

h. finding a synchronous time ST by the CCT of the compliant device, wherein the synchronous time ST is in the time range of (CT−

q, CT+q) so that CLEK=E(H(M(LNC∥

CHALLENGE, H(ST)))) is same as the received CLEK, wherein CT is the current time of the clock on the CCT of the compliant device, and q is a constant;

i. authenticating the user if the received ST is within the time range of (CT−

q, CT+q); and

j. rejecting the request of rendering the protected digital content if no such a ST is found.

25. Software stored on a computer readable medium for causing an offline system to perform functions to authenticate a user to render a piece of protected digital content stored in a compliant device in the offline system with a content publisher, a compliant device, a service server and a token provider, wherein the compliant device has a core content token (CCT) installed therein, wherein the service server has a uniquely global identifier (SC) and are adapted for providing a content license (CL) of the piece of protected digital content, wherein the user has an account established with an account identifier (UserID) in the service server, a hardware token assigned by the token provider, and an owner code (OC) known only by the user and the token provider, wherein the SC and the OC are stored in a database of the token provider, the function comprising:

a. generating two pairs of RSA public and private keys (PU_FOR_PUBLISHER, PR_FOR_PUBLISHER) and (PU_FOR_TOKEN, PR_FOR_TOKEN) by a consortium joined by the content publisher, the compliant device manufacture, and the token provider such that

(i). the token provider is assigned the public key PU_FOR_TOKEN;

(ii). the content publishers is assigned with the same public key PU_FOR_PUBLISHER; and

(iii). private keys PR_FOR_PUBLISHER and PR_FOR_TOKEN are stored in the core content token (CCT) installed in the compliant device,

b. packaging the digital content as a piece of the protected digital content by the content publisher;

c. requesting the content license (CL) of the protected digital content by the user from the service server;

d. providing a license exposed key (LEK) by the user with the hardware token to the compliant device; and

e. authenticating the offline user by the compliant device for rendering the protected digital content based on the received LEK and the content license.