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-=-=-<< Cracking the EAN Barcode System by Moe1 The EAN or European Article Number System Barcode has 13 values, making it easy to spot. Value 1 is situated outside the "left hand side" border. Together with the second digit, it tells us the origin of the product. Values from 3-12 give's us the article code. And value 13 is a checksum which checks the validity of all the other numbers. The checksum is calculated as follows: 1. Add all the odd position numbers except the last digit (1+3+5+7+9+11) 2. Add all the even position numbers (2+4+6+8+10) and multiply the answer by 3. (Note that we are leaving out the last digit, which is our checksum) 3. Add the answer in 1 with the answer in 2. 4. We divide the sum of 1 and 2 by the number 10 and if the remainder is not zero, then we substract the remainder from 10 and this should give us our last positioned number. Once the checksum is done, we know that the barcode is valid. Now on to the lines (yeah doze pesky lines above the values) Note: 7 lines make's up 1 value. There are 3 graphic codes that are used and we have 2 groups of values as explained above. From those 3 graphic codes, 2 codes (A,B) are used in the first group of values and code (C) is used in the second group of values. Below shows us the different graphic code that makes up the different numbers of the values. Take notice of the different lines. BLACK LINE REPRESENTED BY 1 WHITE SPACE REPRESENTED BY 0 CODE A CODE B CODE C if code A were: | if code B were: | if code C were: 0 ----> 0001101 | 0 ----> 0100111 | 0 ----> 1110010 1 ----> 0011001 | 1 ----> 0110011 | 1 ----> 1100110 2 ----> 0010011 | 2 ----> 0011011 | 2 ----> 1101100 3 ----> 0111101 | 3 ----> 0100001 | 3 ----> 1000010 4 ----> 0100011 | 4 ----> 0011101 | 4 ----> 1011100 5 ----> 0110001 | 5 ----> 0111001 | 5 ----> 1001110 6 ----> 0101111 | 6 ----> 0000101 | 6 ----> 1010000 7 ----> 0111011 | 7 ----> 0010001 | 7 ----> 1000100 8 ----> 0110111 | 8 ----> 0001001 | 8 ----> 1001000 9 ----> 0001011 | 9 ----> 0010111 | 9 ----> 1110100 NOTE: only in group 1 are CODE A & B used, in group 2 it's all CODE C. So look at group 1 and identify which CODE forms the number. EXAMPLE: I buy a Sunday Times Newspaper, and I look at the bottom of the front page and see a nice little barcode. Due to my curiosity I wanna know how that shit works so I decide I wanna try and crack that scheme those newspaper boys use. First I look at the numbers and find that there are 13 numbers (9 770039 533008) immediately I know that they are using the EAN system. Since I know how to crack this system, its no problem. I first do a checksum to see if any screws up occur... 9+7+0+9+3+0 = 28 (7+0+3+5+3+0) x 3 = 54 28+54 = 82 82 divided by 10 = 8 remainder 2 10 - 2 = 8 = CHECKSUM (value 12 or 13th position no. in barcode) Ok Checksum done. Now we see what makes up 770039 and we find that its the code pattern: ABBABA And our code pattern for 533008 is: CCCCCC (check and see the lines would be exactly the same as the lines in CODE C) Right so we know: BARCODE: 9 770039 533008 977 tells us its a book or some sort of reading material 770039 is ABBABA and 533008 is CCCCCC and our checksum is 8 I took the Sunday Times Newspaper for an example because it seems it's the easiest to do. If you still dont understand how barcodes can be of any assistance to you then "ERM" think harder. < Wyze1: Amonst a couple of other things - Think IDs > Bye! Moe1 (moe1@mailbox.co.za)