Access Control in A Data Processing System Using Data Item Signatures

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.

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.

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.