QRCodes are Fun, Easy, and Useful for Links, Payments and Identity Verification
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ArcBlock Technical Learning Series Presents an introduction to QRCodes. We scan QRCode for payment, links and basically everything. How do QRcodes work? Are QRcodes secure? Why can I put a logo in the middle of QRCode and it still works? In this talk, we will show you how the QRCode is being drawn. Also, we will talk about Reed-Solomon error correction inside QRCode that makes it fault tolerant. 二维码源于日本，如今世界各国都在使用。一张简单的二维码蕴藏了不简单的信息。二维码究竟是如何画出来的？二维码安全吗？为何在二维码中加个图标还能被扫出来？卫星通讯中用到的Reed-Solomon纠错码如何被用在了二维码中？本次讲座为您揭晓二维码的生成原理，听完保证可以get手绘二维码技能。 https://www.arcblock.io
QRCodes are Fun, Easy, and Useful for Links, Payments and Identity Verification
- 1. QR Code Brought to you by Boshan Sun 1
- 2. Why QR code? 2
- 3. Why QR code? 3
- 4. Why QR code? 4
- 5. Why QR code? 5
- 6. How QR code works? . "show me the money" ↓ +---+------------+---+ | | ## ## | | +---+ # # # +---+ | # # # # | | # # ## # | | # # # # # # | +---+ # ## # | | | # # # # | +--------------------+ ↓ "show me the money" 6
- 8. QR code structure 8
- 12. Structure: timing patterns 12
- 13. Structure: dark module 13
- 14. Structure: reserved format areas 14
- 15. Structure: reserved version areas 15
- 16. Structure: data & ecc 16
- 17. Structure: quite zone 17
- 18. Encoding mode numeric 12345 9527 alphanumeric "hello world 123" kanji "自動車車車" byte "doughnut doughnut doughnut giraffe" "你好, 世界!” 18
- 19. Byte mode encoding mode indicator 0100 count indicator 0001 0001 encoded data 0111 0011 ... terminator 0000 padding byte 1110 1100 0001 0001 show me the money 0100 0001 0001 0111 0011 0110 1000 0110 1111 0111 0111 0010 0000 0110 1101 0110 0101 0010 0000 0111 0100 0110 1000 0110 0101 0010 0000 0110 1101 0110 1111 0110 1110 0110 0101 0111 1001 0000 19
- 20. Error correction coding ? Reed-Solomon ? Galois Field GF(256) ? Polynomial long division 20
- 21. Reed-Solomon 21
- 22. Galois Field 22
- 23. Polynomial long division . message polynomial rs_ecc = -------------------- generator polynomial 0100 0001 0001 0111 0011 0110 1000 0110 1111 0111 0111 0010 0000 0110 1101 0110 0101 0010 0000 0111 0100 0110 1000 0110 0101 0010 0000 0110 1101 0110 1111 0110 1110 0110 0101 0111 1001 0000 65,24,54,134,247,114,6,214,82,7,70,134,82,6,214,246,230,87,144 -------------------------------------------------------------- 0,87,229,146,149,238,102,21 87,3,122,77,183,109,202 0101 0111 0000 0011 0111 1010 0100 1101 1011 0111 0110 1101 1100 1010 23
- 24. Data + ecc . 0100 0001 0001 0111 0011 0110 1000 0110 1111 0111 0111 0010 0000 0110 1101 0110 0101 0010 0000 0111 0100 0110 1000 0110 0101 0010 0000 0110 1101 0110 1111 0110 1110 0110 0101 0111 1001 0000 0101 0111 0000 0011 0111 1010 0100 1101 1011 0111 0110 1101 1100 1010 24
- 25. Matrix so far 25
- 26. Fill in the data 26
- 27. Data masking 27
- 28. Mask 0 28
- 29. Mask 1 29
- 30. Mask 2 30
- 31. Mask 3 31
- 32. Mask 4 32
- 33. Mask 5 33
- 34. Mask 6 34
- 35. Mask 7 35
- 36. Apply masks 36
- 37. Apply masks 37
- 38. Penalty rules 38
- 39. Rule 1 39
- 40. Rule 2 40
- 41. Rule 3 41
- 42. Rule 4 42
- 43. And the winnder is… 43
- 44. Mask 3 44
- 48. Almost done 48
- 49. Finished 49
- 50. Customize QR code 50
- 51. Customize QR code 51
- 52. Customize QR code 52
- 53. Customize QR code 53
- 54. Padding with 0 54
- 55. XOR the mask 55
- 56. XOR the mask 56
- 57. Draw the pattern bits 57
- 58. Some work 58
- 59. Some work 59
- 60. 60