Midnight, I received a voice message. A developer with five years of experience choked up and said: "My 3 million dollar study abroad fund is gone." His wife clicked on an "Airdrop Claim" link, and the family account assets were instantly transferred to a black hole address. He ended with a chilling remark: "I thought as long as the code was secure, that was enough. Turns out, the vulnerability was right in the living room."

Such crash cases are so common in the crypto world that they’re frightening. Someone took a screenshot of their mnemonic phrase and uploaded it to a cloud drive named "123456," only to be completely locked out by ransomware later; someone transferred funds over a public Wi-Fi at a coffee shop, and their address was tampered with; another person wrote their private key in a phone memo, lost the phone, and their account was emptied in two hours. After seeing so many of these cases, I realized one thing: the risk of crypto assets is ninety-nine percent not about technology, but about daily habits and human vulnerabilities.

I’ve summarized three life-saving rules: avoiding just one pitfall is like earning yourself an extra house.

**Rule 1: Mnemonics must be physically isolated**

Mnemonics are the lifeline of assets, but most people have fallen into traps—storing on their phones, uploading to the cloud, or "backing up" via WeChat. These ideas seem cautious but are actually extremely dangerous. The cost for hackers to attack is far lower than you imagine.

The most reliable method I’ve used is simple and straightforward: buy a fireproof and corrosion-resistant metal plate (costs a few dozen yuan), write the mnemonic by hand with a pen, and lock it in a home safe. If you don’t have a safe, find a hidden spot to store it—most importantly, keep it far away from any electronic devices.