Patent ID: 11880832
Assignee: THALES DIS FRANCE SAS
Field: Digital communication (Electrical engineering)
Classification: CPC G  H | IPC G  H

Claim 7:
8. A communication device comprising:
a processor; and
a memory coupled to the processor and storing a transaction application that includes instruction to cause the processor to perform operations for enhancing security of the communication device when conducting transactions, defined by transaction data, using the communication device including instructions to cause the processor to:
receive from a key management server a provisioning package including a bound session key generated by the key management server and encrypted with a transport key, said bound session key being bound, using a reversible function, to a specific context defined with a binding preventing data, the first binding preventing data related to a transaction wherein said binding of said session cryptographic key to said binding preventing data prevents unauthorized use and/or access of an unbound session cryptographic key so that any change in the specific context corrupts the unbound session cryptographic key during a subsequent unbinding phase, the provisioning package further including an encrypted transport key, wherein the encrypted transport key is an encryption of the transport key using a static key;
during computation of a transaction cryptogram corresponding to the transaction, to:
retrieve the static key;
recover the transport key by decrypting the encrypted transport key received in the provisioning package using the static key;
recover the bound session cryptographic key received in the provisioning package using the recovered transport key;
determine the unbinding preventing data and to unbind the bound session cryptographic key from the specific context using the determined unbinding preventing data using an inverse function of the reversible function, whereby a determined unbinding preventing data not equal to the binding preventing data results in a corrupted unbound session cryptographic key whereas a determined preventing data equal to the binding preventing data results in an unbound session cryptographic key that is not corrupted; and
compute the transaction cryptogram using a one-way cryptographic hash function to the transaction data using the unbound session cryptographic key, wherein the transaction is authorized or rejected based on whether the computed transaction cryptogram is an expected transaction cryptogram or a not expected transaction cryptogram.