I've spent eight years analyzing on-chain data and have seen more cases of lost coins than I can count. But what happened at 3 a.m. yesterday almost made me spit my coffee all over the keyboard—the voice message that suddenly blew up in our WeChat group chat.

It was from Old Lin, a seasoned player I’ve known for five years, and this time he was really panicking. I still remember the first thing he said in a hoarse voice: "All the money I saved for my son's overseas studies is gone! Three million! All because my wife pressed a 'confirm' button!"

I was stunned—who is Old Lin? An early miner, always so cautious that he set up three layers of passwords even for two-factor authentication on exchanges. How could someone like him lose his wallet?

I took a deep breath and asked, "Did you send the mnemonic through a chat app? Or take a photo and store it on your phone?"

There was about ten seconds of silence on the other end. That silence was even more unsettling than his earlier shouting.

The story was so absurd it left me speechless: Before going on a business trip, Old Lin was worried his wife wouldn’t know how to operate the wallet, so he took a screenshot of the 12-word mnemonic, thoughtfully labeled the steps “Step 1, 2, 3,” and sent it straight to the family group chat. To make it even clearer, he recorded a demonstration video.

And the result? His wife followed his "tutorial" step by step, and six transfers later, a total of three million USDT was swept clean. When he contacted customer support, their reply was ice-cold: "Our system shows you voluntarily authorized these operations; we cannot be held responsible."

This isn’t a misoperation—this is literally handing the keys to your safe directly to a thief!

Honestly, in this space, "security" is never just a slogan written in a whitepaper—it’s a lesson learned with real blood and money. There are three ironclad rules I recommend you engrave in your mind—their importance is on par with remembering your own birthday password:

**Rule #1: Your mnemonic is your life—never let it touch any device with a screen**

I've seen too many people save their mnemonic in phone notes, WeChat favorites, or even synced to a cloud drive—bro, how is that any different from writing your bank card PIN on your forehead? Hackers dig up this stuff easier than you scroll through short videos.

The right way? Get a piece of 304 stainless steel (the anti-rust, corrosion-resistant kind), use a steel stamp or laser engraver to permanently mark the mnemonic, then lock it in a safe. Don’t think it’s too much trouble—compared to three million, this is nothing.

(More security advice to come—stay tuned for the next part)