Access Control in A Data Processing System Using Data Item Signatures

Abstract

A device maintains multiple signatures, including at least one signature for each of a plurality of data items. At least corresponding signature for a data item is based at least in part on a given function of at least some of the contents of that data item. The device receives a particular sequence of bits and determines at least one signature for that particular sequence of bits, based at least in part on the given function of at least some of the particular sequence of bits. The device determines, based at least in part on the signature for the particular sequence of bits, and using the multiple signatures, whether the device may access the particular sequence of bits.

1 . A device comprising hardware including at least one processor, and software, in combination with said hardware:
 to maintain at said device a list of multiple signatures, said list comprising at least one signature for each of a plurality of data items, wherein, for each of the plurality of data items, at least one corresponding signature for that data item is based at least in part on a given function of at least some of the contents of that data item, wherein two identical data items have the same signature as determined by said given function;   to receive at said device, from a location distinct from said device, a particular sequence of bits;   to determine at least one signature for said particular sequence of bits, the at least one signature for the particular sequence of bits being based at least in part on the given function of at least some of the particular sequence of bits;   to determine, based at least in part on said at least one signature for said particular sequence of bits, and using said list of multiple signatures, whether said device may access the particular sequence of bits; and   if it is determined that said device may not access the particular sequence of bits, to cause access to the particular sequence of bits to be denied.   
     
     
         2 . The device of  claim 1  wherein the device is operable in a network of computers, the device further comprising software, in combination with said hardware:
 to obtain the list of multiple signatures from a computer in the network of computers. 
 
     
     
         3 . The device of  claim 1  wherein the list of multiple signatures is stored in a table on said device. 
     
     
         4 . The device of  claim 1 , further comprising software, in combination with said hardware:
 to add new signatures to said list.   
     
     
         5 . The device of  claim 1 , further comprising software, in combination with said hardware:
 to maintain information relating to data items for which access has been denied.   
     
     
         6 . The device of  claim 1 , wherein the particular sequence of bits represent at least one of: a file, a portion of a file, a digital message, a portion of a digital message, a digital image, a portion of a digital image, a video signal, a portion of a video signal, an audio signal, a portion of an audio signal, a software product, a portion of a software product, and an identifier of a data item. 
     
     
         7 . The device of  claim 1  wherein the given function comprises a hash function or message digest function. 
     
     
         8 . The device of  claim 1  wherein the given function determines at least one signature for the particular sequence of bits using all of the bits in the particular sequence of bits. 
     
     
         9 . A computer-implemented method comprising:
 (A) maintaining, at a device, a list of multiple signatures, said list comprising at least one signature for each of a plurality of data items, wherein, for each of the plurality of data items, at least one corresponding signature for that data item is based at least in part on a given function of at least some of the contents of that data item, wherein two identical data items have the same signature as determined using said given function;   (B) receiving at said device, from a location distinct from said device, a particular sequence of bits;   (C) determining, using hardware in combination with software at said device, at least one signature for said particular sequence of bits, the at least one signature for the particular sequence of bits being based at least in part on the given function of at least some of the particular sequence of bits;   (D) determining, based at least in part on said at least one signature for said particular sequence of bits, and using said list of multiple signatures, whether said device may access the particular sequence of bits; and   (E) based at least in part on said determining, if it is determined that said device may not access the particular sequence of bits, causing access to the particular sequence of bits to be denied.   
     
     
         10 . The method of  claim 9  wherein the device is a computer. 
     
     
         11 . The method of  claim 9  wherein the device is operable in a network of computers, the method further comprising:
 obtaining the list of multiple signatures from a computer in the network of computers. 
 
     
     
         12 . The method of  claim 9  wherein the list of multiple signatures is stored in a table on said device. 
     
     
         13 . The method of  claim 9  further comprising:
 adding new signatures to the list. 
 
     
     
         14 . The method of  claim 9 , further comprising:
 (F) maintaining information relating to data items for which access has been denied.   
     
     
         15 . The method of  claim 9  wherein the particular sequence of bits represent at least one of: a file, a portion of a file, a digital message, a portion of a digital message, a digital image, a portion of a digital image, a video signal, a portion of a video signal, an audio signal, a portion of an audio signal, a software product, a portion of a software product, and an identifier of a data item. 
     
     
         16 . The method of  claim 9  wherein the given function comprises a hash function or message digest function. 
     
     
         17 . The method of  claim 9  wherein the given function determines at least one signature for the particular sequence of bits using all of the bits in the particular sequence of bits. 
     
     
         18 . Computer-readable media tangibly embodying a program of instructions executable by at least one computer, the program comprising code to:
 (a) maintain a list of multiple signatures, at least one signature for each of a plurality of data items, wherein, for each of the plurality of data items, at least one corresponding signature for that data item is based at least in part on a given function of at least some of the contents of that data item, wherein two identical data items have the same signature as determined by said given function;   (b) receive a particular sequence of bits;   (c) determine at least one signature for said particular sequence of bits, the at least one signature for the particular sequence of bits being based at least in part on the given function of at least some of the contents of the particular sequence of bits;   (d) determine, based at least in part on said at least one signature for said particular sequence of bits, and using said list of multiple signatures, whether a device may access the particular sequence of bits; and   (e) based at least in part on said determining, if it is determined that said device may not access the particular sequence of bits, cause access to the particular sequence of bits to be denied.   
     
     
         19 . Computer-readable media as in  claim 18 , the program further comprising code to:
 obtain the list of multiple signatures.   
     
     
         20 . Computer-readable media as in  claim 18 , the program further comprising code to:
 add new signatures to the list of multiple signatures.   
     
     
         21 . Computer-readable media as in  claim 18  wherein the list of multiple signatures is stored in a table. 
     
     
         22 . Computer-readable media as in  claim 18 , the program further comprising code to:
 maintain information relating to data items for which access has been denied.   
     
     
         23 . Computer-readable media as in  claim 18  wherein the given function comprises a hash function or message digest function. 
     
     
         24 . Computer-readable media as in  claim 18  wherein the given function determines at least one signature for the particular sequence of bits using all of the bits in the particular sequence of bits. 
     
     
         25 . A device, the device comprising hardware including at least one processor, and software, in combination with said hardware:
 (a) to maintain at said device a list of multiple signatures, said list comprising at least one signature for each of a plurality of data items, wherein, for each of the plurality of data items, at least one corresponding signature for that data item is based at least in part on a given function of at least some of the contents of that data item, wherein two identical data items have the same signature as determined by said given function;   (b) to receive at said device a particular sequence of bits;   (c) to determine at least one signature for said particular sequence of bits, the at least one signature for the particular sequence of bits being based at least in part on the given function of at least some of the particular sequence of bits;   (d) to ascertain whether or not said at least one signature for said particular sequence of bits corresponds to a signature in said list of multiple signatures; and   (e) based at least in part on whether or not said at least one signature for said particular sequence of bits corresponds to a signature in said list of multiple signatures, to cause access to the particular sequence of bits to be denied.   
     
     
         26 . The device of  claim 25  wherein access to said particular sequence of bits comprises one or more of: (a) copying the particular sequence of bits to or from at least one of a plurality of computers; (b) providing the particular sequence of bits to at least one of a plurality of computers; (c) reading the particular sequence of bits; (d) copying the particular sequence of bits; (e) distributing the particular sequence of bits; (f) modifying the particular sequence of bits; (g) storing the particular sequence of bits; (h) opening the particular sequence of bits; (i) publishing the particular sequence of bits; (j) writing the particular sequence of bits; (k) moving the particular sequence of bits; and (l) deleting the particular sequence of bits. 
     
     
         27 . The device of  claim 25 , wherein the device is operable in a computer network, wherein, based at least in part on whether or not said at least one signature for said particular sequence of bits corresponds to a signature in said list of multiple signatures, the device causes access to the particular sequence of bits to be denied to other devices or computers in the computer network. 
     
     
         28 . The device of  claim 25  wherein the given function comprises a hash function or message digest function. 
     
     
         29 . The device of  claim 25  wherein the given function determines at least one signature for the particular sequence of bits using all of the bits in the particular sequence of bits. 
     
     
         30 . The device of  claim 25  wherein the particular sequence of bits represent at least one of: a file, a portion of a file, a digital message, a portion of a digital message, a digital image, a portion of a digital image, a video signal, a portion of a video signal, an audio signal, a portion of an audio signal, a software product, a portion of a software product, and an identifier of a data item.