Proton's crypto is not Transparent and not OPAQUE

- Blog post by a security researcher analyzing the cryptographic design of Proton (the company behind Proton Mail, Proton VPN, etc.). - "Transparent" and "OPAQUE" are two specific cryptographic protocols: **Transparent** is a widely-used public-key encryption scheme, and **OPAQUE** is a newer, more advanced protocol that prevents servers from ever seeing the user's password (using "password-authenticated key exchange"). - The author argues that Proton claims to use OPAQUE for its "Proton Pass" product but actually implements a weaker variant that doesn't provide the full security guarantees of true OPAQUE — specifically, the server could still learn the password. - This matters because Proton markets itself on privacy and "zero-access encryption"; if their crypto is mis-specified, user trust and actual security may be lower than advertised. - Prior context: Proton has been criticized before for misleading security claims (e.g., its "Swiss jurisdiction" privacy protections, law enforcement compliance issues). The post is part of a longer-running debate about whether Proton's engineering matches its marketing.