SSL and TLS Ciphers

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To further protect the Proton Community, Proton Mail utilizes only high-strength ciphers for SSL and TLS.

We are posting our ciphersuite configurations for Postfix and Apache here for reference, we recommend all system administrators adopt these settings for better security.

Postfix ( main.cf )

smtpd_tls_mandatory_protocols = SSLv3, TLSv1

smtpd_tls_mandatory_ciphers = high

Apache ( ssl.conf )

SSLProtocol -ALL +SSLv3 +TLSv1

SSLCipherSuite HIGH:!aNULL:!MD5

Finally, a quick note regarding TLS 1.2, we will transition to this protocol as soon as CentOS supports it.

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Andy Yen

Andy is the founder and CEO of Proton. He is a long-time advocate for privacy rights and has spoken at TED, Web Summit, and the United Nations about online privacy issues. Previously, Andy was a research scientist at CERN and has a PhD in particle physics from Harvard University.

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