FoxDisc Registered User

Join Date: Jan 2007 Posts: 274

Quote: arnezami Originally Posted by I strongly advise everybody who knows how it was retrieved not to talk about it publicly.



The AACS LA knows the content of the last MKB (can anyone tell me where the "V3" number comes from? Is it built into the MKB?) The last MKB had only 15 S-D sets that matched 15 DKs and 15 PKs (these 15 are in the software branch - there are another 511 non-software branches). Presumably, this PK is one of the 15. Some of the 15 are as small as a single device. One of them is huge (about 2^22), but I strongly suspect that this is not that big set. I'll guess that this PK is one of the other 14, all of which fall within 128 devices. By matching this PK to the MKB released, they narrow the device down, and may have pinpointed it.



Even if the group that matches this PK is not a single device, they may be able to narrow it further. A processing key corresponds to a device key. A device key corresponds to a specific subset difference set, i.e., a specific node on a specific "floor" of the entire tree. The LA knows the matching floor and node numbers. They also know that the matching DK can only be calculated from DKs on this floor that are on the binary tree above this node. Finally they know which DKs have been given out. They may be able to narrow the device down if not all DKs that can calculate this PK have been assigned.



I'd like to know which of these groups match the PK just disclosed. It's something the LA already knows, and it's something that could be calculated with a moderate bit of effort.



Code: umask:uv number 05:0000001C 03:0000002A 05:00000028 03:00000046 02:00000049 02:0000004F 02:00000055 02:0000005B 03:00000069 05:00000068 02:00000085 02:0000008B 04:00000091 07:00000090 17:00000080 On a more serious note, let's look at what the disclosure of this PK tells the AACS LA about where it came from:The AACS LA knows the content of the last MKB (can anyone tell me where the "V3" number comes from? Is it built into the MKB?) The last MKB had only 15 S-D sets that matched 15 DKs and 15 PKs (these 15 are in the software branch - there are another 511 non-software branches). Presumably, this PK is one of the 15. Some of the 15 are as small as a single device. One of them is huge (about 2^22), but I strongly suspect that this is not that big set. I'll guess that this PK is one of the other 14, all of which fall within 128 devices. By matching this PK to the MKB released, they narrow the device down, and may have pinpointed it.Even if the group that matches this PK is not a single device, they may be able to narrow it further. A processing key corresponds to a device key. A device key corresponds to a specific subset difference set, i.e., a specific node on a specific "floor" of the entire tree. The LA knows the matching floor and node numbers. They also know that the matching DK can only be calculated from DKs on this floor that are on the binary tree above this node. Finally they know which DKs have been given out. They may be able to narrow the device down if not all DKs that can calculate this PK have been assigned.I'd like to know which of these groups match the PK just disclosed. It's something the LA already knows, and it's something that could be calculated with a moderate bit of effort. Last edited by FoxDisc; 30th May 2007 at 16:21 .