It's not even considered a good implementation. It's opt-in instead of by default and uses non-standard cryptographic techniques. People who are critical of en

It's not even considered a good implementation. It's opt-in instead of by default and uses non-standard cryptographic techniques. People who are critical of encrypted apps like to use Telegram as the chief boogyman but the real reason that Telegram is preferred by criminals isn't the encryption, it's that Telegram has a history of not moderating at all, allowing huge private groups, and refusing any cooperation with law enforcement or CSAM reporting groups.