ET Explains: Using blockchain to check spam is a work in progress

In the immediate term, the blockchain registration system was able to weed out unregistered spammers. The number of headers being used to send SMSes were reduced by one-third from about 900,000 in 2018 to about 600,000 in 2022. Lookalike headers of SBI, Uber, Amazon, etc. used by spammers were dropped. However, the scale of implementation was so huge that many companies didn't get it right. This led to the failure of 50% messages on March 8, 2021, when telecom companies started filtering their content templates. OTPs from banks, railways, Aadhaar authentication and even with Co-Win registrations needed for Covid vaccinations were disrupted then.