When the SFTP Client (the trading partner) first connects to
Managed File Transfer
(the Server), the encryption algorithm will be negotiated, along with various other connection parameters. Once the encryption algorithm is determined, then the following steps are performed:
The Server will send its public key to the Client.
The Client will generate a random session key and will encrypt it with the Server’s public key.
The Client will then send the encrypted session key to the SFTP server.
The Server will decrypt the session key with the Server’s private key. From then on, all data will be encrypted with that session key.