Postal Letter

How does the Post Office identify counterfeit stamps?

So I was mailing off a letter, and I was thinking, "man, there are a billion different stamp designs out there. I could easily take any picture and print it out on a blank sticker and mail it off." Ok, obviously that would be Mail Fraud and therefore a Federal Offence not worth committing, but wondering if the post office really has any way of identifying fake stamps. They don't seem to be encoded with any anti-counterfeit designs. The following answer is incorrect: "In the U.S., postage stamps are protected by the Information Based Indicia (IBI) technology. IBI is an encrypted 2-dimensional bar code that makes counterfeiting more difficult and easier to detect. Each IBI is unique. It is machine-readable." This techonology is only used as another method for printing stamps for consumers "as needed". My question is in reference to a pre-paid stamp where there is clearly now visible bar code on it. Further, IBI technology has only been developed since the 2000s, though older stamps are still valid for use.

Public Comments

1. WOW I like this question I am interested to know also!
2. I think that they are printed with something invisible to human eyes but that the machines read. This would cost less than having a human check to see if the letters have the correct amount of postage, and would be harder to counterfeit.
3. In the U.S., postage stamps are protected by the Information Based Indicia (IBI) technology. IBI is an encrypted 2-dimensional bar code that makes counterfeiting more difficult and easier to detect. Each IBI is unique. It is machine-readable.
4. Yes there is a way for postal machinery to identify valid postage. But if I told you how, I'd have to kill you.