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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