A company asked me to provide the first six digits of my credit card, along with the last four, to identify a credit charge to my account.
I'm wondering - that's ten of sixteen digits. How secure is it to give away this information? Given that the formula to generate a credit card number is well-known, am I opening myself to any potential issues by disclosing this information?
This is for a Dropbox charge. I have an account with them that I can't access through conventional means (as it was a contractor account for an old workplace) and so they've required me to send this information so that they can verify my identity along with the charge. While it makes sense, I don't remember any companies asking for the first six before (which identifies the carrier and the type of card you have).