Cross-certificate method and device for electric vehicle charging

Abstract

A cross-certificate method is performed by an electric vehicle (EV) for being supplied with power from electric vehicle supply equipment (EVSE) associated with a charging point operator (CPO) having established a trust relationship with a first vehicle to grid (V2G) root certificate authority (rootCA) and a second V2G root certificate authority. The cross-certificate method may include steps of: requesting charging from the electric vehicle supply equipment; receiving, from the electric vehicle supply equipment, a certificate chain held by the electric vehicle supply equipment; and verifying whether or not a last certificate of the certificate chain has been signed by the second V2G root certificate authority, wherein the last certificate of the certificate chain can be a cross-certificate issued by the second V2G root certificate authority.

What is claimed is: 
     
         1 . A cross certification method performed by an electric vehicle (EV) for being supplied with electric power from an electric vehicle supply equipment (EVSE) associated with a charge point operator (CPO) having established a trust relationship with a first vehicle-to-grid (V2G) root certificate authority (CA) and a second V2G root CA, the cross certification method comprising:
 requesting charging from the EVSE;   receiving, from the EVSE, a certificate chain maintained by the EVSE; and   verifying that a last certificate in the certificate chain has been signed by the second V2G root CA.   
     
     
         2 . The cross certification method of  claim 1 , wherein the last certificate in the certificate chain is a cross certificate issued by the second V2G root CA. 
     
     
         3 . The cross certification method of  claim 2 , wherein a public key in the cross certificate coincides with a public key corresponding to a private key used to issue the last certificate excluding the cross certificate in the certificate chain. 
     
     
         4 . The cross certification method of  claim 2 , wherein the last certificate excluding the cross certificate in the certificate chain was issued by the first V2G root CA or the CPO. 
     
     
         5 . The cross certification method of  claim 2 , wherein the second V2G root CA directly issues the cross certificate for the first V2G root CA by itself. 
     
     
         6 . The cross certification method of  claim 2 , wherein the second V2G root CA issues the cross certificate for the first V2G root CA via a cross certification intermediating device. 
     
     
         7 . The cross certification method of  claim 2 , wherein an expiration date of the cross certificate is set before expiration dates of a first V2G root certificate and a second V2G root certificate whichever is earlier. 
     
     
         8 . The cross certification method of  claim 2 , wherein a public key and an identification (ID) in a certificate issued by the first V2G root CA are signed by using a private key corresponding to the cross certificate. 
     
     
         9 . The cross certification method of  claim 2 , wherein a public key and an identification (ID) in a CPO subordinate CA certificate are signed by using a private key corresponding to the cross certificate. 
     
     
         10 . A power transfer method performed by an electric vehicle supply equipment (EVSE) associated with a charge point operator (CPO) having established a trust relationship with a first vehicle-to-grid (V2G) root certificate authority (CA), the power transfer method comprising:
 receiving a charging request from an electric vehicle (EV) trusting a second V2G root CA;   providing a certificate chain maintained by the EVSE to the EV in response to the charging request;   receiving a verification result for the certificate chain from the EV; and   supplying electric power to the EV depending on the verification result.   
     
     
         11 . The power transfer method of  claim 10 , wherein a last certificate in the certificate chain is a cross certificate issued by the second V2G root CA. 
     
     
         12 . The power transfer method of  claim 10 , wherein a last certificate in the certificate chain is signed by the second V2G root CA. 
     
     
         13 . The power transfer method of  claim 11 , wherein a public key in the cross certificate coincides with a public key corresponding to a private key used to issue the last certificate excluding the cross certificate in the certificate chain. 
     
     
         14 . The power transfer method of  claim 11 , wherein the last certificate excluding the cross certificate in the certificate chain was issued by the first V2G root CA or the CPO. 
     
     
         15 . The power transfer method of  claim 11 , wherein the second V2G root CA directly issues the cross certificate for the first V2G root CA by itself. 
     
     
         16 . The power transfer method of  claim 11 , wherein the second V2G root CA issues the cross certificate for the first V2G root CA via a cross certification intermediating device. 
     
     
         17 . The power transfer method of  claim 10 , wherein the certificate chain is sent to the EV in a ServerHello message during a transport layer security (TLS) handshake operation. 
     
     
         18 . The power transfer method of  claim 11 , wherein a public key and an identification (ID) in a certificate issued by the first V2G root CA are signed by using a private key corresponding to the cross certificate. 
     
     
         19 . The power transfer method of  claim 11 , wherein a public key and an identification (ID) in a CPO subordinate CA certificate are signed by using a private key corresponding to the cross certificate. 
     
     
         20 . A cross certification apparatus of an electric vehicle (EV) for being supplied with electric power from an electric vehicle supply equipment (EVSE) associated with a charge point operator (CPO) having established a trust relationship with a first vehicle-to-grid (V2G) root certificate authority (CA) and trusts a second V2G root CA, comprising:
 a processor; and   a memory storing at least one instruction to be executed by the processor,   wherein the at least one instruction, when executed by the processor, causes the processor to:   request charging from the EVSE;   receive, from the EVSE, a certificate chain maintained by the EVSE; and   verify that a last certificate in the certificate chain has been signed by the second V2G root CA.   
     
     
         21 . The cross certification apparatus of  claim 20 , wherein the last certificate in the certificate chain is a cross certificate issued by the second V2G root CA. 
     
     
         22 . The cross certification apparatus of  claim 21 , wherein a public key in the cross certificate coincides with a public key corresponding to a private key used to issue a last certificate excluding the cross certificate in the certificate chain. 
     
     
         23 . The cross certification apparatus of  claim 21 , wherein the last certificate excluding the cross certificate in the certificate chain was issued by the first V2G root CA or the CPO. 
     
     
         24 . The cross certification apparatus of  claim 21 , wherein the second V2G root CA directly issues the cross certificate for the first V2G root CA by itself. 
     
     
         25 . The cross certification apparatus of  claim 21 , wherein the second V2G root CA issues the cross certificate for the first V2G root CA via a cross certification intermediating device.