I’ve been stopped for my signing device before - depending on the model, I’ve gone with, it’s a phone or it’s an encryption key for work. 

 Sir, that’s just my money laundering device 

 My unlicensed and unhosted money transmission device 🤣 

 It signs a cryptographic key that a number guessing computer somewhere records and then a record is stored on a database running in someone’s house. 

 how many bombs did you see on x-ray?  

 multiple phones, lap tops, headphones will get ya too. Happened to me many times. doesn't help that I keep a lock on my bag so they can't open without my permission 🤪 

 Cigars, travel size humidor with humidity meter and earphone wires were pretty rash too. Fortunately it was Cuba. They had probably seen it before.