Twitter's new encrypted DMs aren't better than the old ones

a year ago

Twitter's encrypted DMs were initially flawed, allowing easy key injection and lacking features like sending pictures.
Elon Musk announced 'XChat', a new encrypted messaging platform, but it still has significant security issues.
The new system uses Libsodium's boxes for encryption but lacks forward secrecy, making past messages vulnerable if a private key is leaked.
Twitter's old system had scaling issues and didn't allow new devices to decrypt old messages.
The new approach uses the Juicebox protocol to store private keys, protected by a PIN, but the PIN can be brute-forced relatively easily.
Juicebox's security relies on trustworthy backends, but Twitter controls all backends, making them potentially untrustworthy.
Twitter can still MITM (man-in-the-middle) messages by providing fake public keys, and metadata leakage remains a significant issue.
Signal is recommended as a more secure alternative, offering better encryption and privacy features.

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