Set a screen lock on your phone and a PIN on your SIM card
Grade CBig benefitMoneyFreeLittle timeNo willpower
The SIM card is the small card in your phone; SMS verification codes arrive through it. If you lose the phone, whoever finds it can pull out the card, put it in another phone, collect verification codes, and reset your accounts one by one. A PIN on the card means that when the card moves to another phone, you must enter that code at startup first, and that path is cut off.
- Cost
- No cost. Set the screen lock and the SIM PIN once each.
- Benefit
- After a phone is lost, the fastest move for whoever finds it is to put the SIM in another phone and collect your SMS verification codes. With those codes they can reset your accounts one by one. With a SIM PIN, another phone asks for the code at startup, so they cannot use the card to receive codes. In October 2020 the Ministry of Industry and Information Technology (工信部) reported a real case. After a user’s phone was stolen, they did not suspend the line in time, which left a gap. Wrongdoers used “mobile number plus verification code” to log into a government service app and obtained the user’s ID number and other data. They then changed the mobile service password. The user later suspended the card, and they talked the carrier’s customer service into unsuspending it. Finally they exploited a “forgot password” flaw on a lending platform, reset the payment password, and stole loan funds. MIIT used the case to remind users to set a SIM PIN promptly and to suspend the line immediately when a phone is lost. For the screen-lock half, the US Federal Communications Commission advises setting a strong password on the phone to limit others’ use; when the phone is lost or stolen, that helps stop unauthorized charges and misuse of personal data
- Notes
- Set the PIN under “SIM card lock” in phone settings. Factory default codes are usually 1234 or 0000. 3 wrong entries in a row require the carrier’s PUK code to unlock, so write the PIN on paper after you set it. Rated C because both sources are official reminders plus one case, with no study quantifying how much money a PIN saves. What to do first when a phone is lost is in item 4 (if your phone is lost, follow this order).
Sources · 2
- 工业和信息化部 (2020). 工信部提醒！强化个人信息保护意识. 中国政府网转载工信微报，2020-10-22. app.www.gov.cn/govdata/gov/202010/22/464049/a…
- US FCC. Protect Your Smart Device. fcc.gov/consumers/guides/protect-your-mobile-…