Abstract: Techniques are described for establishing a secure communication channel between a server computer and a client computer. A method includes (a) at the server computer, receiving a command from a user, the command including a secret passphrase, (b) at the server computer, generating a cryptographic key for use by the client computer, (c) at the server computer, storing the cryptographic key within a locked file in encrypted form, the locked file being protected by the passphrase, (d) at the server computer, sending the locked file to the client computer over a network connection, and (e) conducting secure communications between the server computer and the client computer over the network connection, using the cryptographic key for encrypting the secure communications. A corresponding method performed by the client computer is also described. Corresponding computer program products and apparatuses are also described.