Eventually a private key will leak, and without forward secrecy, that private key will probably decrypt all past messages to that person, and all future messages to that person, until they give all their correspondents a new key.
With email, because people quote when replying, you'll get the other side's messages too.
Like, the simple PGP-like system where sender encrypts message using recipient's public RSA key.
And of course it's not improved by switching from RSA to ECIES.
You need to ratchet the key, or double ratchet like Signal protocol.
With email, because people quote when replying, you'll get the other side's messages too.
Like, the simple PGP-like system where sender encrypts message using recipient's public RSA key.
And of course it's not improved by switching from RSA to ECIES.
You need to ratchet the key, or double ratchet like Signal protocol.