There has been an alarming rise in the number of scam calls and SMSes from spoofed numbers. On answering these calls, I will hear an automated message warning of some authority investigating a package sent to me.

What is extremely disconcerting is that the calls come from spoofed numbers that belong to regular Singaporeans, meaning that I cannot meaningfully block these numbers. At best the numbers will always change and at worst, the number I block belongs to someone who may, in the future, legitimately need to contact me.

The Infocomm Media Development Authority (IMDA) recently mandated that telcos add the "+" prefix to international calls, but this does not prevent scammers from spoofing local numbers, nor does it address the issue that the legitimate owner of the spoofed number may eventually be inconvenienced. I have had my number spoofed, and have had people call me regarding a missed call I never made.

Why has IMDA not mandated that telcos implement the Stir/Shaken authentication method - which combats caller ID spoofing - that the Federal Communications Commission in the United States has implemented?

The telcos should be required to perform simple verification that the number is not spoofed.

Jonathan Boon