the present invention is generally directed to printed documents which have a bar code authentication means completely covered by a scratch - off layer . because the bar code is not exposed to the public , counterfeiting and tampering with the bar code is prevented or at least inhibited . bar codes have been previously used to authenticate lottery tickets . referring to fig1 there is shown a prior art lottery ticket 2 shown with its bottom side 4 facing upwards . the surface 4 contains instructional material generally designated by the numeral 6 for the ticket and a bar code display 8 containing a plurality of symbols such as bars 10 and spaces 12 capable of identifying an authentic ticket . as shown in the prior art ticket of fig1 the bar code is always exposed , from the time it is sold to the time it is presented to a lottery sponsor for authentication . because the lottery ticket is exposed , a counterfeiter may alter the bar code or attach a new bar code for the purposes of collecting a prize on a counterfeit lottery ticket . in accordance with the present invention , a bar code is used for authentication purposes but , unlike prior art devices , the entire bar code is covered with a scratch - off layer . the bar code may be covered by a separate scratch - off layer or by the same scratch - off layer used to cover the game data . only when the scratch - off layer is removed is the bar code revealed . in the case of separate scratch - off layers , the lottery sponsor may scrutinize any ticket that is presented for collection if the scratch - off layer has been altered or removed . if a single scratch - off layer is used , any attempt to alter the bar code will likely result in an effect on the game data which will also likely be scrutinized by a lottery sponsor . referring specifically to fig2 there is shown a printed document 20 in the form of a lottery ticket in accordance with the present invention which has a bar code 22 imprinted on a surface 24 of the printed document . it will be understood that the surface 24 of the printed document 20 may be the top side or the bottom side of the printed document . the bar code 22 is covered in its entirety by a scratch - off layer 26 . accordingly , when the printed document ( lottery ticket ) is sold , the bar code can not be seen by the purchaser of the lottery ticket . it is only when the scratch - off layer is removed by the lottery sponsor that the bar code becomes visible and can be read by a optical scanner or the like . if the bar code is presented with the scratch - off layer removed , the sponsor may reject the ticket . thus , it is the absence of removal or alteration of the scratch - off layer which itself assists in determining whether a lottery ticket is authentic . the bar code and its overlaying scratch - off layer can be printed on the front side of the lottery ticket along with the game data which is covered by a separate scratch - off layer . referring to fig3 there is shown a lottery ticket 30 having a top side 32 having imprinted thereon game data represented by numeral 34 and a bar code 36 . each of the game data 34 and bar code 36 are covered by separate scratch - off layers 38 and 40 , respectively . in this embodiment of the invention , the bar code remains hidden until the scratch - off layer is removed by a lottery sponsor to reveal the bar code . the bar code is then read by a scanner and if it is a member of a predetermined list , then the lottery ticket is authenticated . counterfeiting by replacement of alteration of the bar code is determined because in order to engage in such activity the scratch - off layer would have to be removed . in another embodiment of the invention , a single scratch - off layer covers both the game data and the bar code . referring to fig4 there is shown a printed document 50 in the form of a lottery ticket having a top side 52 having imprinted thereon game data 54 and a bar code 56 , each covered by a single scratch - off layer 58 . the game data bar code may be printed anywhere in the designated area covered by the scratch - off layer so long as each can be read by the human eye and an optical scanner or the like , respectively . thus , the game data 54 can be imprinted around the bar code as shown specifically in fig4 or superimposed thereon . all that is required is that the purchaser of the ticket be able to read the game data to see if a prize has been won . of course , the lottery sponsor must be able to read the bar code to authenticate the lottery ticket . the type of bar codes that can be used in the present invention is unlimited . both one dimensional bar codes and two dimensional bar codes can be used . two dimension bar codes are preferred because they provide the greatest number of symbols in the smallest area . examples of one dimensional bar codes include the universal product code ( upc ), code 39 , interleaved 2 of 5 code , code 93 and code 128 . examples of two dimensional bar codes are the stacked bar code containing several lines of bar code stacked one upon the other . examples include code 16k , code 49 , mlc - d2 and code pdf417 . another two dimensional bar code comprises a matrix code comprised of dots and spaces in a two dimensional matrix . examples of two dimensional matrix codes are code one , vericode code and data matrix code .
a printed document in which a bar code is imprinted on a surface thereof and entirely covered with a scratch - off layer , the removal of the scratch - off layer reveals the entire bar code thereby enabling easy authentication of the printed document .