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Money, Money, Money by Rich Cullen

Cash is Cyber King

Is it really worth using credit cards?

Let’s put aside personal financial management and assess credit cards from a cyber security viewpoint.

Digital Footprints

Each credit card transaction leaves a digital footprint of our spending behaviors. Credit card companies, financial institutions, marketing firms, and potentially hackers now know our spending behaviors. They can deduce your preferences, your geographical locations, and what items your order at restaurants (including how many persons were with you at dinner).

The Telephone Marketing Hack

Let’s hypothesize a hacker had determined you really love rubber ducks because you spend $100 per month at rubber duck related businesses. A robo caller or a clever hacker calls and gives you an offer for a limited edition rubber duck by signing up for an online promotion from your credit card company. All you need to do is visit a special website, log in with your credit card company’s credentials, and complete the online form to redeem this special offer. Now your login credentials were stolen and you gave away personal information.

The Cat is Away and the Mice a Will Play

You are on a vacation and you go out to dinner at a restaurant. Let’s assume this is a restaurant that is unique to the area, which would make the meal more special. You use your credit card. Your digital footprint confirms you are away from your home area. Your credit card company flags the credit card transaction and gives you a call to confirm. In this scenario, a hacker has been monitoring your credit card transactions. The hacker, knowing you are out of town and do not have have a home monitoring / protection system, decides to post on the dark web you are out of town and will sell the address to anyone who wants to burglarize the home.

You Cannot Hack Paper

By know you might be wondering about the protection your credit card offers you. This is definitely true if you catch it in time. The rise of e-statements makes it easy to forgot to check your credit card bills. If you find a fraudulent transaction too late, you are out of luck.

Better Personal Financial Management

Some financial advisers recommend avoiding credit cards or reducing their use to improve financial situations. You may also use it to negotiate a lower price on purchases.


Cash is still very valuable. It cannot be hacked. It can improve your finances. It might be worth considering next time you are at dinner.

A Note from the Author

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About the Author

Miguel is a Principal Security Engineer and is the author of the “Serverless Security “ book. He has worked on multiple serverless projects as a developer and security engineer, contributed to open-source serverless projects, and worked on large military systems in various engineering roles.



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Miguel A. Calles

Author · Engineer · Specializing in startups, serverless & cybersecurity