Signing contracts on the telephone

Internet telephony has developed from a niche product into standard technology in recent years. Most telephone providers switched their background technology to Voice over IP, or VoIP for short, long ago. BITKOM, the German association for information technology, cites the economical rates and additional functions such as interaction between e-mail and voicemail as the primary forces driving this change.

The fusion of telephone and Internet is also resulting in new business forms and services that must be secure against tapping and manipulation. For example, the possibility of concluding or changing contracts by telephone. With this in mind, the security experts at the Fraunhofer Institute for Secure Information Technology SIT in Darmstadt have developed software that provides legally-binding archiving of VoIP telephone calls.

Let’s look at a possible application: A banker talks to a customer. This talk leads to a contract that is to be recorded in order to provide evidence. The banker presses the record button on his or her telephone, and the customer is automatically asked for consent. If the customer confirms, recording begins in accordance with the VoIPS principle, which is based on digital signature technology. The software from SIT divides the telephone calls into intervals and signs the transmitted data packets with corresponding metadata. To keep the separate packages from being stored in the wrong order, each interval is given a distinctive encoded “stamp”. In this way, VoIPS combines all the important information on a stored call into an indivisible chain. Any changes to the calls will be noticed, no matter when the change is made.

VoIPS is suitable for all situations where companies, public authorities, banks or insurance companies want to store calls with a tamper-proof method in order to rule out later legal uncertainties. For example, VoIPS could be used for telephone banking or for recording conversations in hospital operating rooms. Based on the applicable standards for Internet telephony, VoIPS can be installed on any IP telephone system.