CH720073A1 - DEVICE AND METHOD FOR PROCESSING A SECURE ELECTRONIC DOCUMENT - Google Patents

Abstract

A cloud-based server computer (1) and a method for processing a secure electronic document are disclosed, the method comprising: creating and configuring a virtual machine (14) using a configuration file, executing the virtual machine (14), receiving a data set containing confidential information and forwarding the data set to the virtual machine (14), connecting a user's client computer (2) to allow the user to access the confidential information; receiving and forwarding user inputs from the client computer (2) and storing the user inputs in an electronic document associated with the confidential information; retrieving the electronic document from the virtual machine (14) and securely transmitting the electronic document to a document server (3) via the communications interface (13); and terminating and deleting the virtual machine (14).

Description

AREA OF REVELATION

[0001] The present disclosure relates to an apparatus and method for editing a secure electronic document. In particular, the present disclosure relates to a server computer apparatus, method, and computer program product that enable human users to securely edit a secure electronic document.

BACKGROUND OF REVELATION

[0002] When editing a secure electronic document, multiple users are often involved. For example, a first user provides the information relevant to the document, a second user creates the document, and a third user reviews, corrects, and finalizes the document.

[0003] In a typical computer-implemented process in which multiple users collaborate on such a secure electronic document over the Internet, confidential information forming the basis of the secure electronic document is typically uploaded to a server computer and users connect to the server computer via client computers to view the confidential information.

[0004] Typically, the first user creates the document locally on their client computer and uploads it to the server. While the document is typically encrypted during transmission to the server, it is often stored unencrypted on the server. If multiple users are to access or edit the document, the document must be transferred from one user to another or downloaded from the server to other users, often resulting in copies of the document existing in multiple locations, such as the server and the client computers. Alternatively, the secure electronic document may be placed on a file sharing server that allows only selected users access to the document. In this case, the document may often also be copied from the file sharing server to the user's client computer. This poses an unnecessary security risk because the document could be accessed or shared by any of the user's client computers. In addition, after the secure electronic document is completed, copies of the document on the client computers as well as further copies on the file sharing server may remain undeleted. In addition, the data can be retrieved even after the secure electronic document has been deleted using data recovery software.

[0005] A virtual machine is a virtualization of a physical computer system, where the virtual machine includes software-based (or "virtual") hardware, such as a processor, memory, and input/output hardware (e.g., communications interfaces and a user interface). The virtual machine typically comes with a pre-installed operating system and drivers for the emulated hardware. The virtual machine is stored in a computer file in the computer's memory and can run on many types of computers, such as client computers or server computers. Virtual machines are often used to develop software applications and test them for compatibility with various underlying computer hardware or operating systems, or to deploy software applications in a predetermined and fixed computing environment. A virtual machine creates an additional level of separation between a software application running on the virtual machine and the underlying physical computer hardware. Creating, configuring, or running a virtual machine may require virtual machine management software, such as a virtual machine application program, depending on the underlying computer hardware. B. a hypervisor or a virtual machine manager, as is known to those skilled in the art.

[0006] A software application running on the virtual machine will in most cases run no differently than on identically configured physical computer hardware and will be unaware of the fact that it is running on the virtual machine.

[0007] A virtual machine occupies a portion of the memory of the computer on which it is implemented. In particular, the virtual machine occupies a portion of the non-volatile memory (e.g., the hard disk) and, when running, a portion of the volatile memory (e.g., the RAM). The software application running on the virtual machine is provided by the virtual machine with virtual memory, where the virtual memory resides in the portion of the non-volatile and volatile memory of the underlying computer hardware that is occupied by the virtual machine. The virtual memory is typically allocated to the virtual machine at the time the virtual machine is created, but may be dynamically expanded at runtime depending on the computing needs of the virtual machine.

[0008] Similarly, the virtual machine is executed in one or more processing threads of the computer on which the virtual machine is implemented. The software application running on the virtual machine is provided with processing resources of the computer, in particular one or more processors of the underlying computer hardware, which are mediated by the virtual machine. These processors of the underlying computer hardware are provided by the virtual machine as one or more virtual processors.

[0009] Similarly, the virtual machine connects to the Internet or other communications networks through one or more network interfaces of the underlying computer. These network interfaces are provided to the software application running on the virtual machine as one or more virtual network interfaces.

GENERAL DESCRIPTION OF REVELATION

[0010] An object of this disclosure is to provide an apparatus and a method for processing a secure electronic document. In particular, an object of the present disclosure is to provide an apparatus and a method for processing a secure electronic document that do not have at least some of the disadvantages of the prior art.

[0011] According to the present disclosure, these objects are achieved by the features of the independent claims. Furthermore, further advantageous embodiments emerge from the dependent claims and the description.

[0012] The present disclosure relates to a server computer comprising a processor, a memory, and a communications interface. The processor is configured to create and configure a virtual machine using a configuration file, and is configured to store the virtual machine in the memory. The processor is configured to execute the virtual machine. The processor is configured to receive a record containing confidential information via the communications interface, and is configured to forward the record to the virtual machine, wherein the virtual machine stores the record in a virtual memory. The processor is configured to initiate a secure remote session on the virtual machine that connects a user's client computer to the virtual machine via the communications interface, wherein the virtual machine is configured to allow the user to access the confidential information. During the remote session, the processor is configured to receive user input via the communications interface and forward it to the virtual machine. The virtual machine stores the user input in an electronic document associated with the confidential information. The processor is configured to terminate the secure remote session, retrieve the electronic document from the virtual machine through the communications interface, and securely transmit it to a document server. The processor is configured to terminate and delete the virtual machine.

[0013] In one embodiment, the processor of the server computer is further configured to receive, via the communication interface, an access list comprising the user credentials of one or more users, and to configure the access rights for the virtual machine using the access list.

[0014] In one embodiment, the processor of the server computer is further configured to receive and forward a user access request from a user's client computer from the communication interface to the virtual machine. The user access request includes user access information. The processor transmits a user access confirmation to the user's client computer via the communication interface. This occurs when the virtual machine has authorized the user access request using the user access information and the stored user credentials.

[0015] In one embodiment, the processor of the server computer is configured to transmit the user access confirmation to the user's client computer via the communication interface. This occurs after a request message has been transmitted to another device of the user and an appropriate response message has been received from either the client computer or the other device.

[0016] In one embodiment, the virtual machine is further configured to prohibit any installation or execution of software not specified in the configuration file; to allow only predefined network communication via the communication interface; and/or to prohibit copying of data from the virtual machine to the client computer during the secure remote session.

[0017] In addition to a server computer, the present disclosure also relates to a method for processing a secure electronic document. The method includes creating and configuring a virtual machine in a processor of a cloud-based server computer using a configuration file. The method includes storing the virtual machine, by the processor, in a memory of the server computer. The method includes executing the virtual machine in the processor. The method includes receiving a set of data including confidential information via a communication interface of the server computer and forwarding the set of data to the virtual machine. The method includes initiating, by the processor, a secure remote session on the virtual machine that connects a user's client computer to the virtual machine via the communication interface and allows the user to access the confidential information. The method includes receiving user input from the client computer via the communication interface and forwarding it to the virtual machine during the secure remote session. The method includes the virtual machine storing the user input in an electronic document associated with the confidential information. The method includes terminating the secure remote session. The method includes retrieving the electronic document from the virtual machine and securely transmitting the electronic document to a server via the communication interface. The method includes terminating and deleting the virtual machine in the cloud-based server computer, in particular in the processor.

[0018] In one embodiment, the method further receives, via the communication interface, an access list comprising the user credentials of one or more users, and configures, in the processor, the access rights for the virtual machine using the access list.

[0019] In one embodiment, the method further comprises receiving a user access request from a user's client computer via the communication interface and forwarding it to the virtual machine, the user access request comprising user access information. The method comprises transmitting a user access confirmation via the communication interface to the user's client computer after the virtual machine has authorized the user access confirmation using the user access information and the stored user credentials.

[0020] In one embodiment, the method further comprises transmitting the user access confirmation via the communication interface to the user's client computer after transmitting a request message to another device of the user, and receiving an appropriate response message from either the client computer or the another device.

[0021] In one embodiment, the method further comprises configuring the virtual machine in the processor to prohibit the installation or execution of any software not specified in the configuration file and to allow only predefined network communication via the communication interface and/or to prohibit the copying of any data from the virtual machine to the client computer during the secure remote session.

[0022] In addition to the server computer and method for processing a secure electronic document, the present disclosure also relates to a computer program product comprising a non-transitory computer-readable medium having stored thereon computer program code configured to enable a processor of a cloud-based computer server to execute the method described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present disclosure will be further explained by way of example and without limitation of the invention described in the appended claims with reference to the drawings, in which: Figure 1: shows a block diagram schematically illustrating a server computer for processing a secure electronic document; Figure 2: shows a flow chart illustrating an embodiment for processing a secure electronic document according to the present disclosure; Figure 3: shows a flow chart illustrating a further embodiment for processing a secure electronic document according to the present disclosure.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0024] Reference will now be made in detail to specific embodiments, examples of which are illustrated in the accompanying drawings, in which some, but not all, features are shown. Indeed, the embodiments disclosed herein may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will conform to applicable legal requirements. Wherever possible, like reference numerals are used to refer to like components or parts.

[0025] Figure 1 shows a block diagram schematically illustrating a cloud-based server computer 1 for processing a secure electronic document. The server computer 1 comprises at least a processor 11, a memory 12 and a communication interface 13.

[0026] The server computer 1 is cloud-based, i.e. the server computer 1 is a cloud-based computer system that provides computing resources, including processing and storage capabilities, to client computers 2 or other external devices.

[0027] The processor 11 includes a central processing unit (CPU) for executing computer program code stored in the memory 12. The processor 11 may, for example, include more specific processing units such as application specific integrated circuits (ASICs), reprogrammable processing units such as field programmable gate arrays (FPGAs), or processing units specifically configured to accelerate certain applications.

[0028] The memory 12 comprises one or more volatile (transitory) and/or non-volatile (non-transitory) memory components. The memory components may be removable and/or non-removable and may also be fully or partially integrated into the server computer 1. Examples of memory components include RAM (random access memory), flash memory, hard disks, data storage and/or other data storage. Depending on the embodiment, the memory 12 comprises a database that may be implemented locally on a particular physical device of the server or decentrally, for example distributed on the cloud-based computer system. Computer program code is stored in the memory 12 that is configured to control the processor 11 of the server computer 1 so that the server computer 1 performs one or more method steps and/or functions as described herein.

[0029] In particular, the memory 12 is configured to store a virtual machine 14. Depending on whether the server computer 1 is in operation or not, the virtual machine 14 is stored in the volatile and/or non-volatile memory, as will be explained in more detail below.

[0030] Depending on the embodiment, the computer program code is compiled or uncompiled program code and/or machine code. The server computer 1 is configured to perform one or more steps and/or functions according to the computer program code. In particular, the processor 11 performs the one or more steps and/or functions according to the computer program code. The computer program code defines and/or is part of a stand-alone software application. Those skilled in the art will understand that the computer program code may also be distributed across a plurality of software applications, which software applications may be distributed and executed on a plurality of devices that together form the server computer 1.

[0031] The software application(s) are installed on the server computer 1. Alternatively, the computer program code can also be retrieved and executed on request from the server computer 1. In one embodiment, the computer program code also provides interfaces such as APIs (Application Programming Interfaces) so that functions and/or data of the server computer 1 can be accessed remotely, e.g. via a client application or via a web browser.

[0032] The processor 11 is configured to create and configure a virtual machine 14, store the virtual machine 14 in the memory 12, and execute the virtual machine 14, as will be explained in more detail with reference to Figures 2 and 3. The virtual machine 14 is configured to emulate portions of a computer system, such as hardware, memory, and interfaces. The virtual machine 14 is also configured to have software, such as an operating system, software libraries, and/or drivers.

[0033] The virtual machine 14 provides an emulated, self-contained computing environment for software applications running on it (referred to as guest software) by providing the necessary operating system and other software, as well as emulated hardware, to enable the guest software to run. The guest software, of course, ultimately runs on the server computer 1, with the virtual machine 14 providing an additional hardware abstraction layer.

[0034] By carrying out the steps and/or functions described here in the virtual machine 14 and not on the server computer 1 itself, it is ensured that other processes or software of the server computer 1 cannot access the steps and/or functions mentioned or otherwise interfere with them. The execution of these steps and/or functions is therefore safer. This is because the steps and/or functions are shielded from other processes of the server computer 1 by the virtual machine 14. This also applies to the data stored in the virtual machine 14, to which processes or software running on the server computer 1 have no access outside the virtual machine 14.

[0035] The various components of the server computer 1 are interconnected by interconnections. The term "interconnection" refers to means that enable power transfer and/or data communication between two or more modules, devices, systems, subsystems or other entities. A given interconnection may comprise a wired connection, e.g. via a cable or a system bus, or a wireless connection via direct or indirect wireless transmissions.

[0036] Furthermore, the server computer 1 is connected via a communication interface 13 to one or more networks, which include local area networks such as a local computer network (LAN) and other networks such as the Internet. The communication interface 13 is configured to enable wired and/or wireless data transmission between the server computer 1 and one or more further devices and/or computer systems, in particular the cloud-based computer system, either directly or via an intermediate network. In particular, the communication interface 13 is configured to receive and forward confidential data and login user data.

[0037] A client computer 2, a document server 3 and an optional further client device 4 are communicatively connected to the server computer 1. In particular, the client computer 2, the document server 3 and the optional further client device 4 are connected to the communication interface 13 via one or more networks. These devices typically also comprise a processor, a memory and a communication interface via which they can communicate with the server computer 1. Depending on the embodiment, the client computer 2 and the further device 4 have a human-machine interface (HMI) which comprises output means and/or input means. The output means can comprise a display (with or without touch) and/or a loudspeaker. The input means can comprise a touch interface, a keyboard, a mouse, a pen, etc. The client computer 2 and the further device 4 can be designed as a laptop computer, as a desktop computer, as a server computer, as a smartphone and/or as a computer system comprising several connected computers.

[0038] Depending on the embodiment, the document server 3 is implemented as a server computer and/or as a computer system comprising a plurality of connected computers. It is known to those skilled in the art that some or all of the functionalities described in relation to the document server 3 can also be provided by the cloud-based server computer 1, depending on the embodiment. The cloud-based server computer 1 is particularly well suited to providing a large memory for storing data, for example in a database.

[0039] In the following sections, a series of steps performed by the processor 11 to process a secure electronic document are described with reference to Figures 2-3.

[0040] As shown in Figure 2, in a preparation step S0, the processor 11 is configured to create, configure and store the virtual machine 14 in the memory 12. The processor 11 configures the virtual machine 14 according to the configuration file. In particular, the configuration file stores configuration information required to set up the virtual machine 14 and the processor 11 configures the virtual machine 14 according to the configuration file. During the creation of the virtual machine 14, the processor 11 allocates a portion of the physical memory 13 to the virtual machine 14, this portion of the physical memory 13 being referred to as virtual memory. The virtual memory is used by the virtual machine 14 to store applications and libraries as well as data, in particular a data set containing confidential information and the electronic document associated with the confidential information, as will be explained in more detail below.

[0041] In one embodiment, the configuration file defines access rights and restrictions with respect to the virtual machine 14 as well as the type of operating system running on the virtual machine 14 and/or certain software installed on the virtual machine 14. The dependent claims show further embodiments in which the configuration file contains more configurations to be configured on the virtual machine 14.

[0042] In one embodiment, the virtual machine 14 is configured according to the configuration file such that the virtual machine 14 prohibits the installation or execution of software that is not specified in the configuration file.

[0043] In one embodiment, the virtual machine 14 is configured according to the configuration file such that the virtual machine 14 only allows predefined network communication via the communication interface 13. In particular, secure protocols such as data transmission encrypted with Secure Sockets Layer (SSL) are used.

[0044] In one embodiment, the virtual machine 14 is configured according to the configuration file such that the virtual machine 14 prevents the copying of any data from the virtual machine 14 to the client computer 2 during the secure remote session. Even outside of the established secure remote session, it is not possible to copy data from the virtual machine 14, since access to the virtual machine 14 is only possible during the secure remote session.

[0045] In a step S1, the processor 11 of the server computer 1 is configured to run the virtual machine 14. The virtual machine 14 runs on the processor 11 in one or more processes and provides an operating system and applications to the software running on the virtual machine 14. In particular, the virtual machine 14 is configured to have access to the network via the communication interface 13 of the server computer 1. The processor 11 assigns to the virtual machine 14 a portion of the memory 12, which is referred to as virtual memory, in which the virtual machine 14, including the operating system, the applications, the libraries and other data, in particular the data set described here, are stored. The virtual memory comprises, as explained above, a virtual volatile memory and a virtual non-volatile memory.

[0046] Depending on the embodiment, the processor 11 may temporarily suspend execution of the virtual machine 14, wherein the virtual machine 14 and, depending on the embodiment, all data relating to the applications currently executing on the virtual machine 14, as well as other data currently stored in the virtual volatile memory, are stored in the virtual non-volatile memory.

[0047] In a step S2, the processor 11 of the server computer 1 receives a data set containing confidential information from the communication interface 13 and forwards it to the virtual machine 14. The virtual machine 14 then stores the data set in the virtual volatile memory and/or the virtual non-volatile memory. The reception and forwarding of the data set from the communication interface 13 to the virtual machine 14 depends on the specific implementation of the virtual machine 14, which includes any auxiliary software running on the server computer 1 that is required to implement the virtual machine 14.

[0048] In one embodiment, the storage of the data set is encrypted using the virtual memory. As a result, the data set is also securely stored in the underlying memory 12 of the server computer 1. The encryption of the memory is typically carried out using symmetric encryption, for example according to the Advanced Encryption Standard (AES) 256.

[0049] In a step S3, the processor 11 of the server computer 1 initiates a secure remote session with the client computer 2, which is connected to the server computer 1 via the communication interface 13. The secure remote session enables a user of the client computer 2 to access the confidential information of the data set stored in the virtual memory. A session is a connection-based form of communication between server and client units. Increased security of the session can be provided in various ways, e.g. by encryption and/or authentication. In particular, the client computer 2 accesses the confidential information by temporarily storing a copy of the confidential information in the volatile memory of the client computer 2 so that the user can access this information. Depending on the type of confidential information, accessing the information includes viewing and/or listening to the confidential information via a display and/or a speaker of the client computer 2.

[0050] In one embodiment, the data communication between the server computer 1 and the client computer 2 during the secure remote session is carried out with increased security, in particular with Secure Sockets Layer/Transport Layer Security (SSL/TLS), wherein the secure remote connection is authenticated using a digital certificate provided by a trusted certification authority that vouches for the authenticity of the certificate when validation is requested, and wherein the data transmission is encrypted. In particular, the client computer 2 sends a request message to the server computer 1, whereupon the server computer 1 responds with a response message to the client computer 2, wherein the server computer 1 preferably also sends a digital certificate to authenticate itself to the client computer 2. The client computer 2 then validates the certificate. Optionally, the server computer 1 can also validate the client computer 2 with the digital certificate received from the client computer 2. Establishing the authenticated connection involves generating a common symmetric key that is known to both the server computer 1 and the client computer 2. After establishing the authenticated connection, the data transmitted between the server computer 1 and the client computer 2 is encrypted with the common symmetric key.

[0051] In a step S4, the processor 11 of the server computer 1 receives user inputs from the client computer 2 via the communication interface 13 during the secure remote session. The server computer 1 is configured to forward the user inputs to the virtual machine 14, wherein the virtual machine 14 stores the user inputs in an electronic document associated with the confidential information. The electronic document is associated with the confidential information, for example by being attached to the confidential information or vice versa. Alternatively or additionally, the electronic document is stored together with the confidential information, contains an identifier associated with the confidential information, or otherwise refers to the confidential information. Alternatively, the electronic document is associated with the confidential information by the confidential information identifying or being associated with the electronic document. The user inputs include, for example, keyboard inputs, mouse movements, and/or recorded speech of the user.

[0052] The present disclosure particularly relates to electronic documents containing information in written form. However, the creation, access and editing of other types of documents is also envisaged. These include, for example, audio, graphic and/or video documents.

[0053] The present disclosure is particularly useful for translating confidential data or for creating report documents based on confidential information. For example, the uploaded dataset is a text document in a particular language uploaded by a first user, and the electronic document is a translation of the confidential information of the dataset into another language. The translation in the form of the electronic document is typically created by another second user. A third user, who may be the same as the first user, may proofread or otherwise review the electronic document.

[0054] In one embodiment, the electronic document is stored in the virtual volatile memory and/or the virtual non-volatile memory of the virtual machine 14 during its processing.

[0055] In one embodiment, the electronic document is stored in encrypted form, for example with AES 256, as described above.

[0056] In a step S5, the processor 11 of the server computer 1 terminates the secure remote session to the client computer 2. In particular, the connection between server and client is terminated with the termination handshake of the underlying secure remote session protocol. In a step S6, the processor 11 of the server computer 1 retrieves the electronic document from the virtual machine 14 and transmits the electronic document securely to a document server 3 via the communication interface 13. To do this, the processor 11 loads the electronic document from the virtual volatile memory and/or the virtual non-volatile memory, converts it into a communication protocol packet and sends it to the document server 3. Increased security of the transmission can be provided by encryption and/or authentication.

[0057] In one embodiment, encryption and/or authentication is enabled by using SSL/TLS authentication and encryption of the electronic document.

[0058] In a step S7, the processor 11 of the server computer 1 terminates the virtual machine 14 and deletes the virtual machine 14 in the memory 12. To do this, running processes are stopped and the virtual machine 14 is shut down and then deleted from the server computer 1. In doing so, the processor 11 deletes the electronic document and the data set with the confidential information from the memory 12.

[0059] In one embodiment, the processor 11 deletes the electronic document and the record containing the confidential information in a non-recoverable manner, for example by deleting all encryption keys used to encrypt the electronic document and/or the record, or by overwriting the electronic document and/or the record with random data (or, e.g., zeros), or by turning off power to the virtual volatile memory for a sufficient period of time.

[0060] Figure 3 shows the optional steps S2a to S2d, which can be performed in addition to the steps described above with reference to Figure 2.

[0061] In a step S2a, the processor 11 of the server computer 1 receives an access list comprising the user login data of one or more users via the communication interface 13 and, in a step S2b, configures the access rights for the virtual machine 14 based on the access list. It should be noted that this step can also take place at an earlier point in time and that this information can also be provided in the configuration file of the virtual machine 14.

[0062] In a step S2c, the processor 11 of the server computer 1 receives a user access request from the user's client computer 2 via the communication interface 13, the user access request comprising login information. The processor 11 then forwards the user access request to the virtual machine 14. In particular, as part of establishing the secure remote session between the server computer 1 and the client computer 2, the user sends his user login data to the server computer 1 via the communication interface 13 in order to authenticate himself.

[0063] In a step S2d, the processor 11 of the server computer 1 transmits a user access confirmation to the user's client computer 2 via the communication interface 13 after the virtual machine 14 has authorized the user access request using the user access information and the stored user login data.

[0064] In particular, in one embodiment, when the user access request is transmitted from the processor 11 to the virtual machine 14, the virtual machine 14 initiates an identification process in which the virtual machine 14 checks whether the user name is included in the stored access list. As the authorization process continues, the user password sent by the user is compared with a password stored in the login data within the virtual machine 14. Typically, it is not the user passwords themselves that are compared, but hashed passwords.

[0065] The following sections present further possible sequences of steps that the processor 11 performs to process a secure electronic document.

[0066] In one embodiment, the processor 11 of the server computer 1 transmits the user access confirmation to the user's client computer 2 via the communication interface 13 in a further step and also sends a request message to another device 4 of the user. Either the other device 4 or the client computer 2 sends a suitable response message to the processor via the communication interface 13. In detail, the process of authentication involves the transmission of information from the virtual machine 14 to the other device, which is then sent back to the virtual machine 14 via either the client computer 2 or the other device 4. Typically, this information is generated pseudorandomly or randomly and is only valid for a limited period of time, typically half a minute or less. This linking to another device further increases security, particularly with regard to the login process.

[0067] It should be noted that in the description the computer program code has been associated with particular functional modules and the sequence of steps has been presented in a particular order; however, one skilled in the art will understand that the computer program code may be structured differently and that the order of at least some of the steps could be changed without departing from the scope of the disclosure.

Claims (11)

1. A cloud-based server computer (1) comprising a processor (11), a memory (12) and a communication interface (13), wherein the processor (11) is configured to: create and configure (S0) a virtual machine (14) using a configuration file, and store the virtual machine (14) in the memory (12); execute the virtual machine (14) (S1); receive (S2) a data set containing confidential information via the communication interface (13) and forward the data set to the virtual machine (14), wherein the virtual machine (14) stores the data set in a virtual memory; initiate (S3) a secure remote session on the virtual machine (14) that connects a user's client computer (2) to the virtual machine (14) via the communication interface (13) and allows the user to access the confidential information; to receive (S4) user inputs from the client computer (2) during the secure remote session via the communication interface (13) and to forward them to the virtual machine (14), wherein the virtual machine (14) stores the user inputs in an electronic document associated with the confidential information; to terminate the secure remote session (S5); to retrieve (S6) the electronic document from the virtual machine (14) and to securely transmit the electronic document to a document server (3) via the communication interface (13); and to terminate and delete (S7) the virtual machine (14). 2. The cloud-based server computer (1) according to claim 1, wherein the processor (11) is further configured to: receive (S2a) an access list via the communication interface (13) comprising user login data of one or more users; and configure the access rights for the virtual machine (14) based on the access list (S2b). 3. The cloud-based server computer (1) according to one of claims 1 to 2, wherein the processor (11) is further configured to: receive (S2c) a user access request from the client computer (2) of a user via the communication interface (13) and forward it to the virtual machine (14), wherein the user access request comprises user access information; and transmit (S2d) a user access confirmation to the client computer (2) of the user via the communication interface (13) if the virtual machine (14) has authorized the user access confirmation using the user access information and the stored user login data. 4. The cloud-based server computer (1) of claim 3, wherein the processor (11) is configured to: transmit the user access confirmation to the user's client computer (2) via the communication interface (13) after a request message has been transmitted to another device (4) of the user and a matching response message has been received from either the client computer (2) or the another device (4). 5. The cloud-based server computer (1) according to any one of claims 1 to 4, wherein the virtual machine (14) is configured to: prohibit the installation or execution of software not specified in the configuration file; allow only predefined network communications via the communication interface (13); and/or prevent the copying of any data from the virtual machine (14) to the client computer (2) during the secure remote session. 6. A computer-implemented method for processing a secure electronic document, the method comprising: Creating and configuring (S0) a virtual machine (14) in a processor (11) of a cloud-based server computer (1) using a configuration file, and storing the virtual machine (14) in a memory (12) of the cloud-based server computer (1); Executing (S1) the virtual machine (14) in the processor (11); Receiving (S2) a data set via the communication interface (13) that includes confidential information and forwarding (S2) the data set to the virtual machine (14) of the cloud-based server computer (1); Initiating (S3) a secure remote session on the virtual machine (14) that connects a user's client computer (2) to the virtual machine (14) via the communication interface (13) and allows the user to access the confidential information; Receiving (S4) user inputs from the client computer (2) via the communication interface (13) and forwarding them to the virtual machine (14) during the secure remote session, wherein the virtual machine (14) stores the user inputs in an electronic document associated with the confidential information; terminating (S5) the secure remote user session; retrieving (S6) the electronic document from the virtual machine (14) and securely transmitting the electronic document to a server (3) via the communication interface (13); and terminating and deleting (S7) the virtual machine (14) in the cloud-based server computer (1). 7. The method of claim 6, further comprising: receiving (S2a), via the communication interface (13), an access list comprising user login data of one or more users; and configuring (S2b) the access rights for the virtual machine in the processor (11) using the access list. 8. The method of claim 6 or 7, further comprising: receiving (S2c), via the communication interface (13), and forwarding to the virtual machine (14), a user access request from a user's client computer (2), the user access request comprising user access information; and transmitting (S2d), via the communication interface (13), a user access confirmation to the user's client computer (2) if the virtual machine (14) authorizes the user access confirmation using the user access information and the stored user login data. 9. The method of claim 8, comprising transmitting the user access confirmation via the communication interface (13) to the user's client computer (2) after a request message has been transmitted to another device (4) of the user and an appropriate response message has been received from either the client computer (2) or the another device (4). 10. The method of any of claims 6 to 9, comprising configuring the virtual machine (14) in the processor (11) to: prohibit the installation or execution of software not specified in the configuration file; to allow only predefined network communications via the communication interface (13); and/or to prevent the copying of any data from the virtual machine (14) to the client computer (2) during the secure remote session. 11. A computer program product comprising a non-transitory computer-readable medium having stored thereon computer program code configured to enable a processor (11) of a cloud-based server computer (1) to execute the method of any of claims 6 to 10.