Verification of signed digital documents
First Claim
1. A method of verifying signed digital documents, the method comprising:
- receiving a signed digital document, said signed digital document including an embedded digital signature, the embedded digital signature comprising a distinctive graphical outline and a plurality of line segments that lie along opposite sides of the embedded digital signature thereby allowing the embedded digital signature to be graphically distinguished from contents of the signed digital document, the embedded digital signature overlapping at least some contents of the signed digital document;
generating an intermediate document, said intermediate document excluding the embedded digital signature;
generating a validation output based on user authentication information identifying a signer of the signed digital document and the intermediate document, the validation output comprising a computed value representing the signed digital document before embedding of the embedded digital signature; and
verifying whether the signed digital document was signed by the signer based on a comparison of the validation output to the embedded digital signature.
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Accused Products
Abstract
Methods, apparatus, and systems are disclosed for, among other things, secure passphrase handling for computing devices. In one respect, a method is provided. The method includes receiving a plurality of passphrase elements from an input device. The method also includes performing a sequence of secure delay processing operations, each operation generating a delayed output value from an initial value. The passphrase is verified upon completion of the sequence of secure delay processing operations. Further, initial values of respective secure delay processing operations are based on respective passphrase elements and, for each secure delay processing operation after a first secure delay processing operation, a delayed output value from at least one other secure delay processing operations.
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Citations
19 Claims
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1. A method of verifying signed digital documents, the method comprising:
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receiving a signed digital document, said signed digital document including an embedded digital signature, the embedded digital signature comprising a distinctive graphical outline and a plurality of line segments that lie along opposite sides of the embedded digital signature thereby allowing the embedded digital signature to be graphically distinguished from contents of the signed digital document, the embedded digital signature overlapping at least some contents of the signed digital document; generating an intermediate document, said intermediate document excluding the embedded digital signature; generating a validation output based on user authentication information identifying a signer of the signed digital document and the intermediate document, the validation output comprising a computed value representing the signed digital document before embedding of the embedded digital signature; and verifying whether the signed digital document was signed by the signer based on a comparison of the validation output to the embedded digital signature. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A computing device for verifying signed digital documents, the computing device comprising:
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a data storage configured to store a signed digital document, said signed digital document including an embedded digital signature, the embedded digital signature comprising a distinctive graphical outline and a plurality of line segments that lie along opposite sides of the embedded digital signature thereby allowing the embedded digital signature to be graphically distinguished from contents of the signed digital document, the embedded digital signature overlapping at least some contents of the signed digital document; a signature extractor configured to generate an intermediate document, said intermediate document excluding the embedded digital signature; and a validation output generator configured to; generate a validation output based on user authentication information identifying a signer of the signed digital document and the intermediate document, the validation output comprising a computed value representing the signed digital document before embedding of the embedded digital signature; and verify whether the signed digital document was signed by the signer based on a comparison of the validation output to the embedded digital signature. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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19. A non-transitory computer-readable storage medium including instructions executable by a processor of a device for verifying signed digital documents, the instructions causing the device to:
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receive a signed digital document, said signed digital document including an embedded digital signature, the embedded digital signature comprising a distinctive graphical outline and a plurality of line segments that lie along opposite sides of the embedded digital signature thereby allowing the embedded digital signature to be graphically distinguished from contents of the signed digital document, the embedded digital signature overlapping at least some contents of the signed digital document; generate an intermediate document, said intermediate document excluding the embedded digital signature; generate a validation output based on user authentication information identifying a signer of the signed digital document and the intermediate document, the validation output comprising a computed value representing the signed digital document before embedding of the embedded digital signature; and verify whether the signed digital document was signed by the signer based on a comparison of the validation output to the embedded digital signature.
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Specification