Crypto student accuses WhatsApp of blocking calls to Saudi numbers

A cryptography PhD student has accused WhatsApp of blocking calls to Saudi Arabia phone numbers and deceiving users about why the service does not work with the accounts.

New America Foundation adviser and PhD student studying applied cryptography at the French Institute for Research in Computer Science and Automation (Inria) Nadim Kobeissi wrote in a tweet on Wednesday that the messaging service claims that “they haven't coded in a block of encrypted calls and that a Saudi firewall is dropping connections.” The security researcher added, “Total. Lie.”

He published a detailed takedown of WhatsApp's claims on GitHub. “The only way the Saudi government could have stopped encrypted calls is by also dropping encrypted WhatsApp messages,” he wrote.

He said that the company appears to block encrypted calls to WhatsApp accounts Saudi phone numbers, even when the user is not located in Saudi Arabia. This is contradictory to the service's FAQ, which state only that encrypted calls are unavailable in some countries. “If you are in one of these countries, you will not be able to place or receive calls,” the website states.

WhatsApp, a popular messaging service in the monarchy, is used exclusively for text messaging, according to a survey of Saudi users published in February.

Kobeissi examined WhatsApp's APK binary code, the file format used by the Android application and discovered evidence that “strongly supports” his initial suspicions that WhatsApp blocks encrypted calls based on the country code of the registered phone number.