WO2008127115A1

WO2008127115A1 - Detachable secure videoconferencing module

Info

Publication number: WO2008127115A1
Application number: PCT/NO2007/000133
Authority: WO
Inventors: Ole Hansvold
Original assignee: Ole Hansvold
Priority date: 2007-04-17
Filing date: 2007-04-17
Publication date: 2008-10-23

Abstract

An electronic module is presented comprising functions for encryption and decryption of data streams including associated key management, compression and decompression of streams for video conferencing and embedding of stream describing parameters into or alongside the data streams. The module is based on a tamper-resistant hardware, being based on a card-type form factor for conveniently being operatively attachable to and detachable from a network terminal.

Description

"Detachable secure videoconferencing module"

TECHNICAL FIELD

The present invention relates to detachable security modules for data transmission. Specifically the invention relates to conveniently attachable and detachable integrated hardware/software modules bringing secure video conferencing to standard terminals having little security means.

BACKGROUND AND PRIOR ART

Systems for videoconferencing needing high level of security, e.g. high level corporate or governmental meetings, are today mainly based on proprietary and dedicated terminals, and not on industry-standard, open, general purpose terminals. These dedicated terminals can be expected to support security functions for confidential conferencing. Most such terminals are designed for use in well protected conference rooms, and not for being conveniently portable or transportable in the briefcase outside the office.

Systems for videoconferencing designed for ease of use or low price, e.g. SKYPE, are available for consumer installation on PCs and mobile terminals, but as the terminal is open, the level of security that can be provided via such terminals is limited as encryption/decryption keys will have to be stored in general purpose memory available for other software. This means that if the terminal comes outside the control of the owner or otherwise available to intruders, the keys can easily be copied or manipulated enabling an intruder to make an eavesdropping device that can monitor subsequent video conferences without being detected.

Whereas the high-quality, dedicated, secure terminals are the preferred choice for videoconferencing from the conference room, and will probably remain so, there is a need for enabling users to participate in confidential videoconferencing wherever they are, even via open terminals like mobile phones or PCs and even via wireless networks easily available to eavesdroppers. The present invention can fill this need.

SUMMARY

The present invention is an electronic module comprising functions for encryption and decryption of data streams including associated key management, compression and decompression of streams for video conferencing and embedding of stream describing parameters into or alongside the data streams.

The module is based on a tamper-resistant hardware with a card-type form factor for conveniently being operatively attachable to and detachable from a network terminal.

Generally the present invention is defined by the attached claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Below the invention will be described with reference to the attached illustrating, but not limiting drawings, where fig. 1 describes videoconferencing based on present art proprietary terminals featuring secure storage and use of keys for encryption of the information exchange, fig. 2 shows the structure of a present art open non-tamper-resistant terminal, fig. 3 shows videoconferencing based on both open terminals and proprietary (secure) terminals where the open terminals are secured by the module according to the present invention, fig. 4 shows the same as figure 3 besides that embedding of meta information is added, fig. 5 shows a module-secured open terminal where the compression and decompression functions are moved out of the module to the terminal, and fig. 6 shows a module-secured open terminal where also the encryption and decryption is moved out of the module to the terminal. DESCRIPTION OF PREFERRED EMBODIMENTS The present invention is an easy detachable and highly tamper resistant module (the Module) containing compression and key-based encryption functions and the corresponding key-handling functions for secure videoconferencing and being embedded in a small card or cartridge form factor, for example Integrated Circuit Cards (Smart Cards), USB- and IEEE 1394 dongles, SD card, Multimedia card (MMC) or Subscriber Identity Module (SIM, UIM, RIM and UICC), compact flash, Smart Media, PCMCIA cards. To increase tamper resistance, the various functions shall preferably reside in a single chip inside the Module.

The light-weight form factor makes the present invention easy to carry around and to install it with the necessary facilities for secure videoconferencing in open terminals thereby solving the re-location problem of rugged proprietary terminals.

Different embodiments of the present invention connect to the network terminal using for instance typical socket type connections (SIM, SD-card), via a wire or close proximity wireless communication.

Performing encryption/decryption and key management inside the highly tamper resistant environment of the present invention solves the security problem associated with management of secret keys in open general purpose terminals. Even if an intruder has stolen or otherwise captured the module according to the present invention, the high level of tamper resistance will make it infeasible for the intruder to retrieve the keys necessary to compromise the system.

The present invention also makes it easy for the user to change from using one terminal to another simply by unplugging it from one terminal, e.g. the laptop PC, and plug it into the next, e.g. the mobile phone, a handheld video display unit or a PDA. This level of convenience is not possible with proprietary terminals or with most other security schemes designed for open terminals. Figure 1 describes videoconferencing based on proprietary terminals featuring secure storage and use of keys for encryption of the information exchange. The proprietary terminals, connected to a common network structure - for instance the Internet - comprise 5 modules for key management, data compression, encryption, decryption and data decompression, where the key management supplies the necessary keys to the encryption and decryption modules. Additionally video input means (for instance a camera), audio input means (typically a microphone), video output means ("display") and audio output means (a loudspeaker or similar) are connected to or integrated with the terminal. As the terminal is proprietary, an intruder will not have immediate access to all its construction details, and one can therefore assume that proprietary terminals will have a relatively high level of security compared with open terminals.

Figure 2 on the other hand shows an open terminal for videoconferencing such as a PC or a mobile phone. Open interoperable network terminals do not in general provide for a secure environment for management of secret keys. An example of such a system is the free SKYPE system, downloadable from the Internet to standard network terminals to be used on the Internet.

Figure 3 describes the present invention. In figure 3 the present invention is denoted the Module. The Module, being substantially a secure area by being implemented within tamper-resistant hardware, receives the un-compressed digital audio/video streams (1) coming from the video camera of the open terminal. The digital audio/video streams are compressed to create the compressed outgoing audio/video streams (2) using the compression algorithm (C). The streams are encrypted using a cryptographic key (SK) supplied by the key management part and an encryption algorithm (A) to create the outgoing encrypted audio/video streams (3) which are returned to the open terminal for transmission via the communication network to the other terminals participating in the video conference.

Simultaneously, the Module receives one or more incoming encrypted audio/video streams from the other participating terminals (of the proprietary kind according to prior art or of the open kind together with a module according to the present invention) connected to the communication network. These streams are first decrypted using A inverse and, depending on type of A, the SK or the SK inverse cryptographic key provided by the key management part in the Module, to retrieve the compressed clear text audio/video streams (5). The compressed incoming audio/video streams are decompressed using C inverse to retrieve the un-compressed incoming audio/video streams (6) which are delivered back to the open terminal for presentation to the user via display and speakers. The SKs (and SK inverses) may be fixed for the entire session or may dynamically change during the session.

Prior to the video conference, the Modules in the participating open terminals and possibly other types of terminal security modules may have to synchronize or exchange SKs/SK inverses. This process may involve just the terminals, or be managed by a central key server. SKs/SK inverses may be generated using management keys or distributed using messages encrypted by management keys. Each Module or terminal security module will in such a case have at least one unique management key, and normally also several domain management keys. A domain can for example be all the Modules and terminal security modules associated with the national branch of a multinational company or all the doctors of a group of hospitals.

Domains can also be formed based on sharing of logical privileges in which case the members of the videoconference not only must share the SK/SK inverse, but also have the appropriate privilege to participate. The use of privileges may simplify set-up of video conferences.

A practical realization of the present invention will normally include security mechanisms not allowing the Module to be functional for a user until the identity of the user has been checked and accepted by the Module. An example of an authentication mechanism is the provision of a PIN. Figure 4 illustrates an embodiment with time-stamping of one or more of the data streams. A secure time-stamp that authenticates when the video conference stream was processed by the Module is one of several possible parameters that can be added to describe a video conference stream. Other such session describing parameters are the identity of the Module having processed a video conference stream, geo-location information indicating the location of the Module while it is processing the video stream, and any other parameter characterizing the video stream or the video stream processing. The video conference stream describing parameters can be used to authenticate when a video conference took place, from which locations it took place, who participated, and so on, and as a tool to identify traitors who consciously or un-consciously have made clear text video conference streams available to others than the intended recipients.

The video conference stream describing parameters can be sent alongside the video conference stream or in specific fields in the video conference stream. A characteristic of the present invention is the possible use of compression (C) and decompression (C inverse) functions that supports the secure embedding of video conference stream describing parameters into the video conference stream itself.

As the present invention is highly tamper resistant, and as such embedding of the video conference stream describing parameters are performed on the video and/or audio data while inside the Module and possibly involving for example digital signature or watermarking techniques, the video conference stream describing parameters can obtain a high level of integrity against unauthorized manipulation.

Another embodiment of the present invention shown in Figure 5, is to move the video compression/decompression functions, i.e. C and C inverse out of the module and into the open terminal. The main data exchanged across the interface between the module and the terminal then becomes the clear text and encrypted incoming and outgoing compressed video streams. The advantage of this variant is a less complex Module. The disadvantages are that the terminal must support the appropriate compression/decompression algorithm, and that the above mentioned addition of video stream describing parameters will not obtain the high level of integrity as it will not be performed in the tamper resistant environment of the Module.

Another embodiment of the present invention illustrated by Figure 6, is to move also the encryption/decryption function, i.e. A and A inverse out of the module and into the open terminal. The main data exchanged across the interface between the Module and the terminal then becomes the delivery of SK and SK inverse and optionally configuration messages containing new SKs, management keys, access control data/PIN and/or stream describing parameters. The advantages of this variant are an even less complex Module and the possibility of including the remaining functions in a general purpose device like a Universal Integrated Circuit Card (UICC). The further disadvantages are that the terminal must support also the appropriate encryption/decryption algorithms, and that the SK and SK inverse traffic across the interface may be easier to eavesdrop than the entire compressed or uncompressed video streams present for the other alternatives.

An additional feature of an embodiment of the invention is to provide means for the terminal to download software from the Module where this software is necessary for further communication between the terminal and the Module.

Claims

PATENT CLAIMS

1. An electronic module comprising functions for encryption and decryption of at least one data stream,

CHARACTERIZED BY a tamper-resistant hardware, said hardware having a card-type form factor for conveniently being operatively attachable to and detachable from a network terminal, and means for secure handling of encryption and decryption keys.

2. Module according to claim 1 ,

CHARACTERIZED IN THAT said tamper-resistant card-type hardware is based on one of the following: generic Integrated Circuit Cards (Smart Cards), mobile subscriber identity modules including SIM, UIM, RIM and UICC, memory-cards for portable equipment like SD card, compact flash, MMC card, Smart Media, PCMCIA card, devices to be connected to a USB port like a USB dongle, and devices to be connected to a IEEE 1394 port like a dongle.

3. Module according to one of the preceding claims, CHARACTERIZED BY being arranged to perform functions to synchronize security keys with trusted elements in other network terminals prior to a data stream exchange session.

4. Module according to one of the preceding claims,

CHARACTERIZED IN THAT said module further comprises security mechanisms restricting said module to be functional for a user until the identity of said user has been checked and accepted by said module.

5. Module according to claim 4,

CHARACTERIZED IN THAT said security mechanism is based on entering a PIN- code.

6. Module according to one of the preceding claims, CHARACTERIZED BY said module further being arranged to perform compression and decompression of said data streams.

7. Module according to one of the preceding claims,

CHARACTERIZED IN THAT said module further being arranged to embed stream describing parameters describing at least one of said data streams in a stream exchange session into or alongside at least one of said data streams.

8. Module according to claim 7,

CHARACTERIZED IN THAT said stream describing parameters comprise at least one of secure time-stamps, secure identity of a sender or a receiver, and geo-location data.

9. Module according to one of the preceding claims, CHARACTERIZED BY said module connecting to said terminal directly via a socket type connection, via a wire, or via close proximity wireless communication.

10. Module according to one of the preceding claims, CHARACTERIZED IN THAT said module comprises a mechanism allowing said network terminal to read from said module a software necessary for said network terminal to further communicate with said module.

11. Module according to one of the preceding claims,

CHARACTERIZED IN THAT at least one of said data streams comprise video conferencing data.