He noted: the participants of the terrorist attack used WhatsApp to a greater extent.
Even if the Telegram team complied with the order of the FSB and passed the encryption keys to the special services for access to correspondence, this would not help to find the participants of the terrorist attack in Petersburg on April 3, 2017. This was reported by the creator of the messenger Pavel Durov.
Even if the FSB request was limited to assistance in capturing six terrorists who participated in the terrorist attack in St. Petersburg, we could hardly be of use: some of the mobile numbers that were of interest to the FSB had never had a Telegram account, the other part was automatically deleted for inactivity in the past  ] year.
As noted by Durov, “many people are asking” about whether a compromise solution was possible that would help to avoid blocking Telegram. “I think it’s hardly possible,” he replied.
The keys for decrypting the correspondence of all its users, neither Telegram, nor other messengers, could not issue at all desire. This is due to the technical features of encryption in 2018.
Durov recalled the publication of the Republic of October 31, 2017, according to which to coordinate the terrorist attack in St. Petersburg “more” was used not Telegram, and WhatsApp.
On April 16, the providers began to block Telegram in accordance with the decision of the Tagansky District Court, which decided to restrict access to the messenger due to the refusal to provide the FSB with encryption keys. According to the official version, the secret services wanted to get access to the correspondence of the accused in the terrorist attack in St. Petersburg.