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US 7,013,295 B2Granted
Tagged private information retrieval
AssigneeLucent Technologies Inc.
InventorsBjorn Markus Jakobsson, Claus Peter Schnorr
Life of this patent
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AssigneeLucent Technologies Inc.
InventorsBjorn Markus Jakobsson, Claus Peter Schnorr
Estimating the term…
Purchase of information items from a merchant over the Internet or other network is implemented so as to ensure that the merchant is unable to identify the particular information item(s) purchased by a user. The user when considering purchase of a given information item is permitted to access a corresponding signed ciphertext of that item. The signed ciphertext in an illustrative embodiment includes a first ciphertext portion in the form of a symmetric key encrypted using a public key associated with the merchant, a second ciphertext portion corresponding to the information item encrypted using the symmetric key, an unencrypted description of the information item, and a tag corresponding to a signature. The user requests purchase of the information item by sending a blinded version of the first ciphertext portion to a payment server along with an appropriate payment. The payment server decrypts the blinded version of the first ciphertext portion and returns the resulting symmetric key to the user. The user then utilizes the symmetric key to decrypt the second ciphertext portion so as to obtain the desired information item. The decrypting operation performed by the payment server may be implemented using at least part of a set of multiple rounds, with the user providing a blinded ciphertext and receiving a corresponding decryption result for each of the rounds.
A method for controlling access to one or more information items purchasable from a merchant and accessible over a network, wherein a user interested in a given information item is permitted to access a corresponding signed ciphertext of the given information item, the signed ciphertext having at least a first ciphertext portion, the method comprising the steps of receiving from the user a blinded version of the first ciphertext portion of the signed ciphertext in conjunction with a request from the user for purchase of the given information item from the merchant;
A processor-based system for controlling access to one or more information items purchasable from a merchant and accessible over a network, wherein a user interested in a given information item is permitted to access a signed ciphertext version of the given information item, the signed ciphertext version having at least a first ciphertext portion, and wherein the system is operative:
A machine-readable medium containing one or more software programs for controlling access to one or more information items purchasable from a merchant and accessible over a network, wherein a user interested in a given information item is permitted to access a corresponding signed ciphertext having at least a first ciphertext portion, and wherein the one or more programs when executed implement the steps of:
Dependencies are inferred from the claim text.