5 ms·

Decoding the USPS barcode

117 points by halo 17y ago

Torn 17y ago
Great thread, almost like a mini detective story but involving code!
- unalone 17y ago
  SomethingAwful is, hands-down, the best forum on the Internet. If you've got time, this is probably the quintessential SA drama, and it's epic in scope: http://forums.somethingawful.com/showthread.php?s=1a3f8a1a286abce365091c9f32997535&threadid=1675856&perpage=40&pagenumber=1 http://forums.somethingawful.com/showthread.php?s=1a3f8a1a28... Also from SomethingAwful, though the original post is now archived, the P-P-P-Powerbook prank: http://www.zug.com/pranks/powerbook/ http://www.zug.com/pranks/powerbook/ And, if your day hasn't been thoroughly wasted yet, this is my all-time favorite product of SA: http://lparchive.org/LetsPlay/Animal%20Crossing/index.html http://lparchive.org/LetsPlay/Animal%20Crossing/index.html
  - leftnode 17y ago
    Yup, SA is definitely the best. It's well moderated, tons of knowledgeable people there. Definitely worth the tenbux.
  - Torn 17y ago
    Agreed. Not seen the Animal Crossing LP's yet, but am a big fan of the raocow super mario ones where he plays insanely hard rom-hacks and just rambles and rambles :) http://www.youtube.com/watch?v=8UYFSvsN1CY&feature=channel_page http://www.youtube.com/watch?v=8UYFSvsN1CY&feature=chann...
  - afed 17y ago
    This forum isn't your personal advertising network, Lowtax.
    - pyre 17y ago
      If you're looking for a post that is more like an advertisement look here: http://news.ycombinator.com/item?id=861731 http://news.ycombinator.com/item?id=861731 Just because someone is spreading something be word of mouth doesn't mean that they are necessarily financially invested in the product they are promoting. People do promote products that they enjoy/find useful.
  - idm 17y ago
    I spent the last 6 hours reading about kswizzle. I'm angry at you and also grateful. Or perhaps I don't know how to feel.
    - pkrumins 17y ago
      I spent the last 3 hours. :)
  - numair 17y ago
    From the P-P-P-Powerbook prank website: 3) Finally, and most disturbingly, Jeff was not heard from again. I personally e-mailed him for permission to run his story on ZUG, but after an initial response, I never heard from him again. All of his Web sites have come down, and he is nowhere to be found. ...
kevindication 17y ago
I would love to read this, but I have a policy of not visiting SA while at work.
- Torn 17y ago
  Ok, here's the ghist: - Guy's housing company provides backdated letter of deposit deductions, which they are obligated to provide within 45 days else refund the entire deposit no questions. - Mailing stamp doesn't have a visible date, instead has an encoded datamatrix http://img.skitch.com/20090928-q76qg7y1w575ghbqn4t2uwx4eg.jpg http://img.skitch.com/20090928-q76qg7y1w575ghbqn4t2uwx4eg.jp... - Goons (SA users) tidy up the barcode image with photoshop, and do some internet detectivery to track down the tech specs for the image encoding used: http://www.springerlink.com/content/l847l1357j811101/ http://www.springerlink.com/content/l847l1357j811101/ - Date of mailing turns out to be encoded as 26 90 32 01. Little-endian so, flip and to decimal and it becomes 2009-09-18. Letter is backdated!
  - mp3jeep01 17y ago
    haha, great executive summary Torn!
jballanc 17y ago
This article reminded me of two things: 1. Bar codes are really, really hard to deal with! The complexity of encoding types, physical representation, and in memory representation rivals that of video. I once had to write a system to handle barcodes which included programming the scanner, interpreting the results, and then generating resulting barcodes of the appropriate encoding, correct length, and right checksum. And that was hard with the old 1-D barcodes! 2. Security deposits suck! I got screwed out of one once (not as much as the guy in this thread, though) because, literally, my move-in inspection noted "spots" on the carpet and on move-out the landlord said, "Those look more like splotches to me." Unfortunately, I was moving 2000 miles away, and the cost of pursuing through small claims court wouldn't have been worth it. That's when an uncle taught me a lesson about security deposits: "You're probably going to get screwed at the end, so negotiate like it's not a deposit but a sunk cost."
jrockway 17y ago
Ok, so you decoded the date -- how about finding the signing key for the data. :)

117 points by halo 17y ago

Torn 17y ago

Great thread, almost like a mini detective story but involving code!

unalone 17y ago
SomethingAwful is, hands-down, the best forum on the Internet. If you've got time, this is probably the quintessential SA drama, and it's epic in scope: http://forums.somethingawful.com/showthread.php?s=1a3f8a1a286abce365091c9f32997535&threadid=1675856&perpage=40&pagenumber=1 http://forums.somethingawful.com/showthread.php?s=1a3f8a1a28... Also from SomethingAwful, though the original post is now archived, the P-P-P-Powerbook prank: http://www.zug.com/pranks/powerbook/ http://www.zug.com/pranks/powerbook/ And, if your day hasn't been thoroughly wasted yet, this is my all-time favorite product of SA: http://lparchive.org/LetsPlay/Animal%20Crossing/index.html http://lparchive.org/LetsPlay/Animal%20Crossing/index.html
- leftnode 17y ago
  Yup, SA is definitely the best. It's well moderated, tons of knowledgeable people there. Definitely worth the tenbux.
- Torn 17y ago
  Agreed. Not seen the Animal Crossing LP's yet, but am a big fan of the raocow super mario ones where he plays insanely hard rom-hacks and just rambles and rambles :) http://www.youtube.com/watch?v=8UYFSvsN1CY&feature=channel_page http://www.youtube.com/watch?v=8UYFSvsN1CY&feature=chann...
- afed 17y ago
  This forum isn't your personal advertising network, Lowtax.
  - pyre 17y ago
    If you're looking for a post that is more like an advertisement look here: http://news.ycombinator.com/item?id=861731 http://news.ycombinator.com/item?id=861731 Just because someone is spreading something be word of mouth doesn't mean that they are necessarily financially invested in the product they are promoting. People do promote products that they enjoy/find useful.
- idm 17y ago
  I spent the last 6 hours reading about kswizzle. I'm angry at you and also grateful. Or perhaps I don't know how to feel.
  - pkrumins 17y ago
    I spent the last 3 hours. :)
- numair 17y ago
  From the P-P-P-Powerbook prank website: 3) Finally, and most disturbingly, Jeff was not heard from again. I personally e-mailed him for permission to run his story on ZUG, but after an initial response, I never heard from him again. All of his Web sites have come down, and he is nowhere to be found. ...

kevindication 17y ago

I would love to read this, but I have a policy of not visiting SA while at work.

Torn 17y ago
Ok, here's the ghist: - Guy's housing company provides backdated letter of deposit deductions, which they are obligated to provide within 45 days else refund the entire deposit no questions. - Mailing stamp doesn't have a visible date, instead has an encoded datamatrix http://img.skitch.com/20090928-q76qg7y1w575ghbqn4t2uwx4eg.jpg http://img.skitch.com/20090928-q76qg7y1w575ghbqn4t2uwx4eg.jp... - Goons (SA users) tidy up the barcode image with photoshop, and do some internet detectivery to track down the tech specs for the image encoding used: http://www.springerlink.com/content/l847l1357j811101/ http://www.springerlink.com/content/l847l1357j811101/ - Date of mailing turns out to be encoded as 26 90 32 01. Little-endian so, flip and to decimal and it becomes 2009-09-18. Letter is backdated!
- mp3jeep01 17y ago
  haha, great executive summary Torn!

jballanc 17y ago

This article reminded me of two things: 1. Bar codes are really, really hard to deal with! The complexity of encoding types, physical representation, and in memory representation rivals that of video. I once had to write a system to handle barcodes which included programming the scanner, interpreting the results, and then generating resulting barcodes of the appropriate encoding, correct length, and right checksum. And that was hard with the old 1-D barcodes! 2. Security deposits suck! I got screwed out of one once (not as much as the guy in this thread, though) because, literally, my move-in inspection noted "spots" on the carpet and on move-out the landlord said, "Those look more like splotches to me." Unfortunately, I was moving 2000 miles away, and the cost of pursuing through small claims court wouldn't have been worth it. That's when an uncle taught me a lesson about security deposits: "You're probably going to get screwed at the end, so negotiate like it's not a deposit but a sunk cost."

jrockway 17y ago

Ok, so you decoded the date -- how about finding the signing key for the data. :)