A security card (보안카드, 保安카드, boan kadeu) is an identification card with many sets of numbers that are used for internet or mobile banking. This will come necessary near the end of a transaction as a safety feature to make sure no one hacked your account. The banking site will ask for the first two numbers on a certain line and the last two numbers of another line. In the example below, they want the first two numbers next to 25, which are 56 and the last two numbers next to 16, which are 34.

Image provided by Hi Korea eGovernment for Foreigners.

The front of the card shows the bank and the back of the card has all the important security information. These cards have a special ID number at the top right of the card. This eight-digit code identifies the card and connects the card to your account. Most of the cards displays 30 random number combinations, each four digits long. When you want to complete a transaction, you’ll be asked to enter the first two numbers from a randomly selected section and the last two numbers from another randomly selected section. If you lose your security card, you will get another one with different sets of numbers.

In order not to bring another plastic card in a wallet, some people take a picture of their card and save it on their phone. This is a security flaw as anyone with access to your phone could have access to your security card and accordingly be able to withdraw money. Unfortunately, this is not theoretical as there have been instances in which someone’s account has been hacked and money stolen electronically. During at least one investigation, it was discovered that the victim had a picture of their security card stored within their smartphone. The court has ruled that based on this lapse in security done by the victim, the bank was not responsible for the breach and related theft and therefore was not responsible to repay the stolen funds to the victim. With this in mind, we highly recommend you do not store an image of your security card in your phone or anywhere else.

While plastic and the same size as a credit card, these are slightly thinner so feel different to the touch. When the bank distributes these cards, they come in a semitransparent plastic wrap that is significantly blackened so even the tellers cannot see the numbers. This should be an indication to you that the card should not be shown to anyone, including banking staff.