A method of operating a computer in a cloud network which is untrusted as a cloud-based enterprise application store via which a client computer establishes a connection to an enterprise application executing in an enterprise network which is trusted, comprising: in a login phase, performing a first user authentication for a user of the client computer and receiving security identifiers from the enterprise network, the security identifiers identifying the user as an authorized user of the enterprise network, the first user authentication including transmitting a public key of a private/public key pair of the enterprise network to the client computer and subsequently receiving from the client computer and transmitting to the enterprise network an encrypted password and encrypted key, the encrypted password being a user password encrypted under a first one-use symmetric key, the encrypted key being the first one-use symmetric key encrypted under the public key, the enterprise network decrypting the encrypted key and the encrypted password to obtain the user password for authenticating the user and returning the security identifiers to the enterprise application store; and in a subsequent application launch phase, performing a second user authentication as part of establishing the connection to the enterprise application, the second user authentication including transmitting the encrypted password and encrypted key to the enterprise network and subsequently receiving from the enterprise network and transmitting to the client computer a login ticket, the login ticket including a second one-use symmetric key under which the user password is encrypted and stored in encrypted form within the enterprise network, the client computer subsequently transmitting a connection-establishment message including the login ticket to the enterprise network, the enterprise network decrypting the encrypted form using the second one-use symmetric key from the login ticket of the connection-establishment message to obtain the user password for authenticating the user and establishing the connection of the client computer to the enterprise application. in a login phase, performing a first user authentication for a user of the client computer and receiving security identifiers from the enterprise network, the security identifiers identifying the user as an authorized user of the enterprise network, the first user authentication including transmitting a public key of a private/public key pair of the enterprise network to the client computer and subsequently receiving from the client computer and transmitting to the enterprise network an encrypted password and encrypted key, the encrypted password being a user password encrypted under a first one-use symmetric key, the encrypted key being the first one-use symmetric key encrypted under the public key, the enterprise network decrypting the encrypted key and the encrypted password to obtain the user password for authenticating the user and returning the security identifiers to the enterprise application store; and in a subsequent application launch phase, performing a second user authentication as part of establishing the connection to the enterprise application, the second user authentication including transmitting the encrypted password and encrypted key to the enterprise network and subsequently receiving from the enterprise network and transmitting to the client computer a login ticket, the login ticket including a second one-use symmetric key under which the user password is encrypted and stored in encrypted form within the enterprise network, the client computer subsequently transmitting a connection-establishment message including the login ticket to the enterprise network, the enterprise network decrypting the encrypted form using the second one-use symmetric key from the login ticket of the connection-establishment message to obtain the user password for authenticating the user and establishing the connection of the client computer to the enterprise application.