| 摘要 |
A system and method for key escrow cryptography for use in a system comprising a sender and a receiver. Only public escrow keys are stored in the sender and the receiver. The sender encrypts a message using a secret session key (KS), and generates a leaf verification string (LVS) by combining an unique program identifier (UIP), a public portion of a program unique key (KUpub), and a signature. The sender encrypts the KS using the KUpub to generate a first encrypted session key (EKS), and generates a first law enforcement access field (LEAF) by encrypting a combination of the first EKS and the UIP with a copy of a public portion of a family key (KFpub) stored in the sender. The encrypted message, the LVS, and the first LEAF are transmitted from the sender to the receiver. The receiver stores therein a public portion of the KEPF key (KEPFpub). The receiver extracts the UIP, KUpub, and the signature from the LVS, and then encrypts the KS using the extracted KUpub to generate a second encrypted session key (EKS). The receiver generates a second LEAF by encrypting a combination of the second EKS and the extracted UIP with a copy of the KFpub stored in the receiver. The receiver then compares the first LEAF to the second LEAF. If the first LEAF is equal to the second LEAF, then the receiver decrypts the encrypted message using the KS.
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