A method for accessing a data store of a cloud computer system via a gateway computer system, wherein the gateway computer system is assigned an IP address, and wherein the gateway computer system is connected via a network to the cloud computer system, wherein the cloud computer system is assigned a URL, wherein the gateway computer system stores authentication data of a user for authentication to the cloud computer system and at least one cryptographic key, wherein in an operating system of a terminal device of the user a DNS is defined, said method having the following steps: - transferring a request from the terminal device to the DNS defined in the operating system via the network in order to call up an IP address of the cloud computer system which is assigned to the URL of the cloud computer system, - answering the request by the DNS by transferring the IP address of the gateway computer system to the terminal device, wherein an assignment of the URL of the cloud computer system to the IP address of the gateway computer system is stored in the DNS, - setting up a protected connection between a first terminal device of the user and the gateway computer system, wherein the protected connection is set up in accordance with the TCP/IP protocol with the IP address of the gateway computer system, - transferring a file from the terminal device to the gateway computer system over the protected connection, - setting up a session between the gateway computer system and the cloud computer system over the network, - authenticating the user to the cloud computer system by the gateway computer system through the session in that the gateway computer system accesses the authentication data of the user stored in the gateway computer system for the authentication of the user. - encrypting the file by the gateway computer system using the cryptographic key, - transferring the encrypted file from the gateway computer system to the cloud computer system through the session, - storing the encrypted file in the data store of the cloud computer system. - transferring a request from the terminal device to the DNS defined in the operating system via the network in order to call up an IP address of the cloud computer system which is assigned to the URL of the cloud computer system, - answering the request by the DNS by transferring the IP address of the gateway computer system to the terminal device, wherein an assignment of the URL of the cloud computer system to the IP address of the gateway computer system is stored in the DNS, - setting up a protected connection between a first terminal device of the user and the gateway computer system, wherein the protected connection is set up in accordance with the TCP/IP protocol with the IP address of the gateway computer system, - transferring a file from the terminal device to the gateway computer system over the protected connection, - setting up a session between the gateway computer system and the cloud computer system over the network, - authenticating the user to the cloud computer system by the gateway computer system through the session in that the gateway computer system accesses the authentication data of the user stored in the gateway computer system for the authentication of the user. - encrypting the file by the gateway computer system using the cryptographic key, - transferring the encrypted file from the gateway computer system to the cloud computer system through the session, - storing the encrypted file in the data store of the cloud computer system.