Reader, writer and method for programmable tags

Abstract

A tag writer, reader and method are disclosed. The tag writer is operable to generate a security identifier during writing of data to the tag, the security identifier being dependent on one or more of the data written, data already on the tag, metadata associated with the data, the tag and/or the writing of the data.

What is claimed is: 
     
         1 . A tag writer for a programmable tag, the tag writer being operable to generate a security identifier during writing of data to the tag, the security identifier being dependent on one or more of the data written, data already on the tag, metadata associated with the data, the tag and/or the writing of the data. 
     
     
         2 . The tag writer of  claim 1 , wherein the security identifier is a selected one of a checksum, hash or encrypted digest. 
     
     
         3 . The tag writer of  claim 1 , wherein the tag writer is arranged to write the security identifier to a remote data repository for future authentication of the tag and security identifier. 
     
     
         4 . The tag writer of  claim 1 , wherein the security identifier is derived from security status data held by the tag and/or content of a user memory area of the tag. 
     
     
         5 . The tag writer of  claim 1 , wherein at least a part of the security identifier is written integrally to the data on the tag, wherein reprogramming of the tag changes or deletes the security identifier. 
     
     
         6 . The tag writer of  claim 3 , wherein the tag includes a unique identifier, the tag writer being arranged to link the security identifier to the unique identifier in the remote repository. 
     
     
         7 . The tag writer of  claim 6 , wherein the unique identifier is physically written on one or more of the tag and its packaging and is obtained from the tag and/or packaging for writing of the security identifier to the remote repository. 
     
     
         8 . The tag writer of  claim 1 , wherein the tag writer is further arranged to write data on the tag from which the security identifier is derived to a backup data repository. 
     
     
         9 . The tag writer of  claim 1 , wherein the tag writer is operable to use a subset of data on the tag to generate the security identifier. 
     
     
         10 . The tag writer of  claim 9 , wherein a pattern to determine the subset is encoded for the tag in a remote data repository, the tag writer being arranged to retrieve the pattern and use it to determine the subset. 
     
     
         11 . The tag writer of  claim 1 , wherein the tag is an RFID tag. 
     
     
         12 . A tag reader operable to read data from a memory of a programmable tag and generate a security identifier from the read data, the tag reader being arranged to compare the security identifier to a previously calculated security identifier for the tag to authenticate the data in the memory. 
     
     
         13 . The tag reader of  claim 12 , wherein the tag has a unique identifier, the tag reader being arranged to use the unique identifier to retrieve the previously calculated security identifier from a remote data repository. 
     
     
         14 . The tag reader of  claim 13 , wherein the unique identifier is physically written on the tag or its packaging, the reader including a user interface to receive the unique identifier. 
     
     
         15 . A method for writing to a programmable tag comprising:
 generating a security identifier during writing of data to the tag, the security identifier being dependent on one or more of the data written, data already on the tag,   metadata associated with the data, the tag and/or the writing of the data; and,   storing the security identifier for future authentication of the tag and security identifier.   
     
     
         16 . The method of  claim 15 , wherein the step of storing includes writing the security identifier to a remote data repository for future authentication of the tag and security identifier. 
     
     
         17 . The method of  claim 15 , further comprising deriving the security identifier from security status data held by the tag and/or content of a user memory area of the tag. 
     
     
         18 . The method of  claim 15 , further comprising writing at least a part of the security identifier integrally to the data on the tag, whereby reprogramming of the tag changes or deletes the security identifier. 
     
     
         19 . The method of  claim 16 , wherein the tag includes a unique identifier, the step of writing including linking the security identifier to the unique identifier in the remote data repository. 
     
     
         20 . The method of  claim 19 , wherein the unique identifier is physically written on one or more of the tag and its packaging, the method further comprising obtaining the unique identifier from the tag and/or packaging for writing of the security identifier to the remote repository.