Inspired by this question

Also, not a duplicate of this question as it's focused on image only deposit.

Since checks can be deposited via an image (mobile deposit), it seems like it would be extremely easy to deposit the same check image to multiple accounts. I do not think banks do real-time checks with other banks to make sure the check number has not been used already.

A slightly more complicated question, what if some enterprising thief uses information from a data breach to photoshop a new account and routing number onto the check, and then cash it multiple times across multiple accounts?

Wondering how banks protect themselves against this as checks seem extremely insecure.


The main vector I'm trying to protect myself against is someone in a foreign country with lax laws and regulations getting a copy of the check image, then "cashing it" over and over again.

It seems like a thief in a foreign country would able to evade justice pretty easily, and I'm not sure what the U.S. government could really do to stop them.

By safe, I mean as safe a credit cards, which have several consumer protections in place. It seems like checks are inherently unsafe as your account and routing number are written on them, as well as your name and home address. Credit cards are at least beginning to push chip payments and online services such as PayPal have guarded against double charges (i.e. cashing a check twice).

With credit cards and PayPal, Venmo, etc, I'm trusting a single company that I have a significant history with to not lie or steal from me. That company implements checks to prevent unauthorized charges on their systems.

With checks, it seems like you are handing every individual who handles it, and every individual who can get a picture the ability to clean out your account online.

EDIT 2 (addressing duplication):

Pre-mobile banking the check cashing thief would have to walk into a bank/check cashing store and physically present the check to get money. This made counterfeiting checks harder for 2 reasons

1) Checks are usually printed on special paper and have security features that make it impossible to copy via photocopier. Thus skill and equipment are involved.

2) The counterfeiter must be present in the country to cash the check. Eventually, their luck will run out and they'll get arrested.

Because checks can be cashed via images now, none of the security features are any use, and the counterfeiter can operate out of a country that won't care about check fraud. I was looking for answers that address this type of fraud in particular.

  • 1
    Banks have internal programs to detect duplicate checks being deposited against the same account. More generally, though, is that the economy works on honesty; there aren't enough thieves to destabilize things, and the thieves that do exist get caught.
    – RonJohn
    Jun 18, 2019 at 20:37
  • 1
    I'm going to put on my security.stackexchange.com hat for a minute and ask you some clarifying questions. What threat vector are you trying to protect yourself against? From which perspective are you concerned (a customer, or the bank)? What's your definition of safe - do you mean safer than some other method?
    – dwizum
    Jun 19, 2019 at 15:39
  • @dwizum - see long-winded edit Jun 19, 2019 at 15:59
  • 1
    Possible duplicate of Can't the account information on my checks be easily used for fraud?
    – Ben Voigt
    Jun 19, 2019 at 16:28
  • 2
    Regarding "I'm not sure what the U.S. government could really do to stop them" -- the US government doesn't have to. The US banks simply do not send the money to the foreign country on the instruction of a personal check, which makes it the problem of the foreign bank (who gave out the money and wants it back) and the foreign criminal justice system. There's a reason that foreign transactions use credit cards, wire transfers, or travelers' checks -- because virtually no one accepts out-of-country personal checks.
    – Ben Voigt
    Jun 19, 2019 at 16:33

2 Answers 2


What you are asking here could also be put on Stack Overflow because it is as much a computer science question as a finance one. Banks have many ways to protect from checks being used twice including machine learning programs to hopefully identify if the same check is being used twice; however, it does happen that they can be used more than once.

One: The way that banks protect themselves is through their policies where if they see a check has already been cashed, they will take money from the person who already cashed it and give it to the second casher. This seems like it could be abused with people stealing checks which is why banks recommend you destroy the check once it has been cleared and the money enters you account. You can read more here.

Two: To your point about photoshop, it would be super hard to photoshop something that the algorithms won't pick up. But say you can, right? It still wouldn't work because the name on the check would not match up with the new number that you put on the check. The number on the check is the account number for the sender not the receiver. The banks programs would notice this and flag the check.

  • Any support why photoshop would be difficult to catch? Jun 18, 2019 at 21:16
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    You don't need photoshop. Everyone can order blank checks for self-printing, with any account number he cares to specify - this is standard for businesses printing checks. The core point is you will get caught, and the money will be removed form your account.
    – Aganju
    Jun 18, 2019 at 22:28
  • @sevensevens I didn't say it was hard to catch. I said it was hard to get past the algorithms AKA it is easy to get caught Jun 18, 2019 at 22:50
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    @Vality Yes. At some point, all those "copies" of the cheque will make their way back to the bank of the issuer of the check who will realise that there are five claims on the same money. At least four of those would be clawed-back (possibly, since all the recipient accounts would need to be in the same name, they would claw-back all five and start fraud investigations).
    – TripeHound
    Jun 19, 2019 at 6:59
  • 1
    Interesting on the destroying checks link. My bank requires that I keep the checks for 60 days after they have accepted a mobile deposit. It's curious how she didn't know her check was stolen, too.
    – topshot
    Jun 19, 2019 at 12:07

First and foremost, I think it's important to remember that things are illegal and there are courts and jails to ultimately handle people that contravene laws.

If you have the ability to deposit a check in to an account, then "know your customer" vetting applies; so the bank has seen and recorded two forms of identification and verified your address. This is why a major part of fraud scams include getting access to the account of a patsy to use as the vehicle for illegal activity.

Most banks (I think it's actually all, but I'll go with most for the inevitable outlier) that allow mobile deposit are outsourcing that task to a vendor and enter in to fraud liability agreements where the vendor absorbs some responsibility for fraud. While it is true that funds verification at the bank level is not done in real time, I'm sure the vendors performing the mobile deposit function are doing other checks to guard against this sort of check fraud.

Rest assured that there are behind the scenes fraud prevention tools in place.

  • 3
    I work (via outsourcing) for one of those vendors. In fact, one of the servers I manage has DEDUP in it's name.
    – RonJohn
    Jun 18, 2019 at 20:38

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