Latest Posts
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Cryptoperiods Explained: How Long Should Keys Live and Why It Matters
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There are some topics in security that sound very deep and complicated at first. Cryptoperiods is one of those. The first time I encountered this in a real project, I honestly thought it was something only big banks cared about. Later on, when I got more involved with HSMs, RKI processes, and PCI requirements, I…
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Understanding Cryptographic Keys: The Beginner Friendly Breakdown
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Whenever I talk to people who are new in security or payments, one thing always surprises me. The moment I say the word keys they immediately think it is something complicated or something only seniors can understand. I get that feeling because I used to be the same. When I first touched topics like symmetric…
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What is NIST SP 800-57? A Practical Guide for Payments, Fintech, and Security Teams
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I want to share something that honestly took me years to fully understand. If you work in fintech, in payments, or anywhere near security and compliance, you will eventually hear this one document again and again. It is called NIST SP 800 57. To be honest, the first time I saw it, it felt like…
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EMV Cryptograms Explained: ARQC, TC, and AAC Made Simple
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I want to talk to you about something that confused me a lot back when I first started working with EMV transactions. If you are like me, when you hear the word cryptogram, it feels like something advanced or very deep. But once I actually saw how this is used in real payment flows, I…
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TVR, TSI and IAC: The Brains Behind EMV Logic
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When I first started working on EMV transaction processing, I remember feeling completely lost looking at those cryptic acronyms such as TVR, TSI and IAC. They looked like random three-letter codes, but every time something went wrong in an EMV transaction, those were the first places I had to check. If you’ve ever debugged an…
About Me
Hi I’m Assi—I’m dedicated to advancing cashless payment technology and sharing insights with fellow developers and solution architects on my blog, Cashless Nomad.
I embrace a mobile lifestyle by replacing cash with digital payments, enabling seamless transactions anywhere. Going cashless keeps me connected, agile, and financially flexible—perfect for traveling light and skipping currency hassles.
Checkout my other blogs at marai.dev