Why is my bank asking for KYC?

Excuse me, but I'm a bit confused. I've been a long-time customer of my bank, and suddenly they're asking me to provide Know Your Customer (KYC) documentation. Can you explain why this is necessary? I've never had to do this before, and I'm wondering if it's a standard procedure or if there's a specific reason behind it. Additionally, I'm concerned about the security of my personal information. Could you assure me that my data will be kept SAFE and secure during this process? Thank you for your time and consideration.