Patent ID: 8074073
Filing Date: 2011-12-06
Classification: H04L

Abstract:
1. A method for operating a public-key encryption scheme which provides for sending a digital message M between a sender and a recipient with participation of an authorizer, wherein the digital message is encrypted by the sender and decrypted by the recipient, the method comprising encrypting, by at least one machine in a set of one or more machines, the digital message M using at least a recipient public key RPUB and a recipient encryption key RENC to create an encrypted digital message for decryption with a recipient private key RPRIV and a recipient decryption key RDEC, wherein: the recipient public key RPUB and the recipient private key RPRIV form a public key/private key pair 1, wherein the recipient private key RPRIV is a secret of the recipient; the recipient decryption key RDEC is generated by the authorizer using at least a key generation secret of the authorizer and the recipient encryption key RENC, wherein the recipient encryption key RENC and the recipient decryption key RDEC are a public key/private key pair 2; wherein the recipient encryption key RENC is generated from information comprising the identity of the recipient, the recipient public key RPUB, and a parameter defining a validity period for the recipient decryption key RDEC.