Document modification detection and prevention
First Claim
Patent Images
1. A computer-implemented method comprising:
- receiving, by a computing device processor, an electronic document including content items, a rule, a first digital signature provided by a first author, and a second digital signature provided by a second author, wherein the rule defines a user-modifiable content item included in the electronic document;
generating a digest for the electronic document by digesting all of the content items except for at least the user-modifiable content item that is defined by the rule, such that the user-modifiable content item is ignored in the digest generation; and
invalidating at least one of the digital signatures if the digest indicates a difference in any of the digested content items;
wherein if the digest indicates no difference in any of the digested content items, the method further comprises (a) subsequently receiving a user input attempting to create a new state of the electronic document, (b) determining whether the user input is allowed by the rule, and (c) invalidating at least one of the digital signatures if the user input is not allowed by the rule; and
wherein the rule applies differently to the first and second authors, such that the user input causes the first digital signature to be invalidated but does not cause the second digital signature to be invalidated.
2 Assignments
0 Petitions
Accused Products
Abstract
Methods and apparatus, including computer program products, implementing and using techniques for document authentication. An electronic document is presented to a user. The electronic document has data representing a signed state and a current state. A disallowed difference between the signed state and the current state is detected, based on one or more rules that are associated with the electronic document. A digital signature associated with the electronic document is invalidated in response to the detecting.
-
Citations
16 Claims
-
1. A computer-implemented method comprising:
- receiving, by a computing device processor, an electronic document including content items, a rule, a first digital signature provided by a first author, and a second digital signature provided by a second author, wherein the rule defines a user-modifiable content item included in the electronic document;
generating a digest for the electronic document by digesting all of the content items except for at least the user-modifiable content item that is defined by the rule, such that the user-modifiable content item is ignored in the digest generation; and invalidating at least one of the digital signatures if the digest indicates a difference in any of the digested content items; wherein if the digest indicates no difference in any of the digested content items, the method further comprises (a) subsequently receiving a user input attempting to create a new state of the electronic document, (b) determining whether the user input is allowed by the rule, and (c) invalidating at least one of the digital signatures if the user input is not allowed by the rule; and wherein the rule applies differently to the first and second authors, such that the user input causes the first digital signature to be invalidated but does not cause the second digital signature to be invalidated. - View Dependent Claims (2, 3, 4, 5, 6, 7)
- receiving, by a computing device processor, an electronic document including content items, a rule, a first digital signature provided by a first author, and a second digital signature provided by a second author, wherein the rule defines a user-modifiable content item included in the electronic document;
-
8. A computer readable storage device storing a computer program which, when executed by one or more computer processors, causes the one or more computer processors to perform operations comprising:
-
receiving, by a computing device processor, an electronic document including content items, a rule, a first digital signature provided by a first author, and a second digital signature provided by a second author; generating a digest for the electronic document by digesting all of the content items except for at least a first user-modifiable content item that is ignored in the digest generation based on the rule; and invalidating at least one of the digital signatures if the digest indicates a difference in any of the digested content items, wherein the rule is applied differently to content items associated with the first and second authors such that generating the digest causes the first digital signature to be invalidated but does not cause the second digital signature to be invalidated. - View Dependent Claims (9, 10, 11, 12)
-
-
13. A computer-implemented method comprising:
-
receiving, by a computing device processor, an electronic document including content items, a rule, a first digital signature provided by a first author, and a second digital signature provided by a second author; generating a digest for the electronic document by digesting a portion of the content items, wherein a user-modifiable content item is not digested; and invalidating at least one of the digital signatures if the digest indicates a difference in any of the digested content items, wherein if the digest indicates no difference in any of the digested content items, the method further comprises; subsequently receiving a user input attempting to create a new state of the electronic document; determining whether the user input is allowed by the rule; and invalidating at least one of the digital signatures if the user input is not allowed by the rule, wherein the rule is applied differently to the first and second authors such that generating the digest causes the first digital signature to be invalidated but does not cause the second digital signature to be invalidated. - View Dependent Claims (14, 15, 16)
-
Specification