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US 6,446,051 B1Granted
Document transfer systems
AssigneeHewlett-Packard Company
InventorDipankar Gupta
Life of this patent
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AssigneeHewlett-Packard Company
InventorDipankar Gupta
Estimating the term…
A document transfer system enabling a consumer to obtain a document from an owner upon payment using a cryptographic protocol involving the consumer, the owner, a document source, such as printer, and a mediator, according to which protocol the consumer requests a document, the owner provides the source with first and third portions of the key and provides the mediator with a fourth portion of the key, which fourth portion can combine with said first portion to generate the complete key, the consumer provides the owner with the payment and the owner provides the source with a second portion of the key which can combine with said first portion to generate the complete key. A printer for use in the above system, the printer comprising a document memory for storing a received encrypted document, a key memory for storing a first cryptographic key portion, a processor for receiving a second cryptographic key portion and combining it with the first key portion to form a complete cryptographic key which is supplied to a decrypting module. The encrypted document is supplied to the decrypting module whereupon the document is decrypted and supplied to the consumer.
A cryptographic method of enabling a consumer to obtain a document from an owner upon payment, the method comprising a step of using of a protocol involving the consumer, the owner and a document source, wherein the source requires knowledge of a key in which said document is encrypted in order to provide said document, said key comprising a first portion and a second portion, the protocol comprising the following sequential steps:
A cryptographic method of enabling a first party to obtain an item of value from a second party upon receipt by said second party of a second item of value, the method comprising the use of a protocol involving the first party, the second party and a source of said first item of value, wherein the source requires knowledge of a key in order to provide the said first item of value, the protocol comprising the following sequential steps:
A fair exchange method of enabling a consumer to obtain a document from an owner upon receipt of a payment including the following steps:
A printer for use in enabling a consumer to obtain a document from an owner upon a payment, the printer comprising:
Dependencies are inferred from the claim text.