Patent Publication Number: US-2022239705-A1

Title: Processing sensitive information over voip

Description:
BACKGROUND 
     a. Field of the Invention 
     Contact centres are extensively used by service providers for delivering services to, and communicating with, customers. Contact centres typically comprise a large group of agents taking or making telephone calls with customers. Contact centres often use call recording technologies, where an audio recording of the customer conversation is stored, and/or screen recording technologies, where a video or static snapshot of the agent&#39;s computer terminal is stored in order to aid in staff training, customer complaint management, compliance monitoring or record-keeping. 
     In many contact centre transactions the customer is either required to confirm his identity by providing the answer to security-based questions, or to provide his payment card details to pay for a transaction. The nature of much of this information is highly sensitive. In particular, the information can include passwords, personally-identifiable information such as a date of birth, a PIN, a memorable phrase, bank account numbers, credit card security codes and the like. 
     Data and identity theft, as well as fraudulent financial transactions, are widespread, and so it is of particular interest to the caller to keep secret as much of the information as possible. Disclosing personally-sensitive financial or other security information to a contact centre agent has the potential to increase personal data loss in a number of ways. For example, the contact centre agent can write down or memorise the customer&#39;s information for later use. It has even been known for agent&#39;s to make their own personal recordings of the information using their personal mobile phones or devices. 
     Furthermore, where audio or video recordings or screen shots are recorded, such data is vulnerable to fraudulent access. 
     The Payment Card Industry (“PCI”) has developed a Data Security Standard (DSS) for businesses that store, process and/or transmit credit card data. 
     Compliance with the PCI security standards is not optional for such businesses. The DSS dictates the methods and ways in which companies processing credit card data (including telephone-based credit card transactions) can store card and personal data. Regulations and guidelines such as these have a direct impact on contact centre which take customers&#39; sensitive data in telephone conversations. 
     Secure telephony payment systems have been developed which can be used in order to allow potentially sensitive information such as payment card information to be transmitted directly to a payment processing system whilst preventing such information being transmitted in any form to the contact centres agent or contact centre agent terminal. In general a call is routed via the secure system and the system uses one of a number of various techniques such as suppression of Dual Tone Multi Frequency (DTMF) tones or muting the caller&#39;s voice stream in order to prevent potentially sensitive data from reaching the contact centre. 
     Contact centres have complex telephony systems optimised to provide bulk routing of calls at minimum cost. The majority of calls into the contact centre may not typically contain sensitive information, but it is important for the contact centre to be able to handle sensitive information securely should the need arise during any call handled by the contact centre staff. It is therefore desirable, but more expensive, to route all calls through the secure telephony system prior to entry into the contact centre. As the proportion of an individual call actually containing the sensitive information is small compared to the total length of the call it is not desirable or cost effective to use the secure telephony payment system for the entire duration of the call. 
     Ideally the secure telephony payment system would only be utilised for the relatively short period of time whilst secure information is being relayed to the payment processing system, but would be available for use by other transactions once the part of the call requiring transmission of secure information is complete. 
     However, it is problematic to switch a secure telephony payment system in and out of the call path once the call has been received by an agent in the contact centre. The process typically involves terminating the call and the contact centre agent calling back the original caller on a secure line. Alternative methods, such as creating a conference call with the secure payment system are ineffective as the sensitive data will still be detectable within the contact centre telephony system and therefore the advantage of removing the sensitive data from the contact centre is lost. Processes to place the caller ‘on hold’ within the public telephony system (i.e. external to the contact centre) whilst the contact centre agent is disconnected and reconnected via the secure payment system are also typically problematic as, for efficiency, in most contact centre systems when a call is terminated the agent handling the call generally becomes free again and available for subsequent calls. Hence the agent handling the initial call might not be available once the call returns to the centre via the secure payment system. 
     Historically calls have been routed using circuit switched connections in the public switched telephone network (PSTN). A caller would call the contact centre via the PSTN and the call centre private branch exchange (PBX) and the Automatic Call Distribution (ACD) system would connect the caller to an agent. All signalling was transmitted over the voice channel and the signalling and voice were very much bound together. 
     However, with the advent of Voice over Internet Protocol (VoIP) technologies signalling and voice are generally transmitted using different protocols from one another. VoIP isn&#39;t a protocol itself. Rather, VoIP is an umbrella term for a set of protocols involved in transporting voice information using IP. VoIP protocols include Session initiation Protocol (SIP), Media Gateway Control Protocol (MGCP) and H.323, for example. Whilst VoIP protocols are not yet standardised, SIP appears to be emerging as a popular choice. For secure transmissions of SIP messages over insecure network links, the protocol may be encrypted with Transport Layer Security (TLS). 
     SIP doesn&#39;t encode audio information in a phone call, nor does it transport audio information. SIP simply initiates and terminates communications sessions, for example the session may be a voice call between two people or a video conference between a whole team. 
     The job of SIP is to set up a call, conference or other interactive communication session and terminate it when it&#39;s over. This is achieved by sending messages between endpoints known as “SIP addresses.” SIP doesn&#39;t do much during the session itself as its primary purpose is to establish the session and then end it. Therefore, the bandwidth of a SIP signalling stream is relatively small, for example, approximately 5 Kbps. 
     The session media (for example speech/voice or image data/video) is transmitted via a separate media stream. SIP can be used in conjunction with various protocols that specify and carry the session media. Media type and parameter negotiation and media setup is performed using Session Description Protocol (SDP), which is carried as payload in SIP messages. 
     Before voice can be sent over IP, it is encoded using a voice codec to convert audio signals into data. 
     The encoded packets of audio data are usually sent using Real-time Transport Protocol (RTP) or Secure Real-time Transport Protocol (SRTP), specialised application-layer protocols for transporting audio and video data when real-time streaming is necessary. 
     Signalling or media stream packets are themselves transmitted using transport layer protocols such as Transmission Control Protocol (TCP) or User Datagram Protocol (UDP). TCP is a protocol designed to transmit packets in an ordered sequence and to retransmit any packets that are lost along the way. Packet headers specify the order of each packet in the sequence. If packets are received out of order, they can be reordered at the receiving end. UDP is a protocol designed to transmit data without retransmission of lost packets or detection of out-of-sequence packets. 
     UDP is better than TCP for voice streams. Lost and out-of-sequence packets can cause audio quality issues, but usually these aren&#39;t detectable by the human ear. The amount of delay caused by the re-ordering and retransmission of TCP packets can ultimately result in much worse audio quality problems. SIP signalling streams on the other hand are usually transmitted using TCP. 
     Two of the most common codec standards are G.711 for uncompressed digital voice and G.729 codec for compressed voice. The bandwidth of the media stream is relatively large compared to that of the signalling stream, for example the bandwidth of an uncompressed voice stream is likely to be 100 Kbps. Compression degrades audio quality in order to reduce the amount of data transmitted in order to reduced the amount of bandwidth consumed by the call. However, compression usually corrupts Dual Tone Multi-Frequency (DTMF) tones which have been sent over the voice stream. 
     Historically this problem has been overcome by using ‘out of band’ DTMF whereby DTMF tones are detected and sent using an uncompressed voice stream. Alternatively the DTMF data may be sent as separate packets in the RTP stream. More recently the data represented by the detected DTMF tone is sent over a SIP signalling stream associated with the voice stream. 
     b. Related Art 
     In United Kingdom patent application number 1604668.2 a secure data collection system is described which uses an on demand appliance (ODA) in the contact centre to place a call out to a secure data collection system whilst sensitive data is transmitted. The secure data collection system prevents the sensitive data from reaching the agent. However, the sensitive data is routed through the ODA, which is located in the contact centre, to the secure data collection system. Whilst any security risk may be mitigated by physical security measures to prevent access to the ODA it is undesirable for the sensitive data to ever pass through the contact centre. 
     The separation of the signalling stream from the voice stream allows for a novel and inventive solution to the problem of processing sensitive information over VoIP. 
     SUMMARY OF THE INVENTION 
     According to the invention there is provided a method of processing, by a call processor, a media call comprising the steps of: receiving a first signalling stream from a first entity; creating a second signalling stream to a second entity; forwarding signals received from the first signalling stream to the second signalling stream; receiving a third signalling stream from the second entity; creating a fourth signalling stream to the first entity; and forwarding signals received on the third signalling stream to the fourth signalling stream; the first signalling stream containing instructions to set up a media call between the first entity and the second entity such that media is transmitted over a first media stream from the first entity to the second entity and a media is transmitted over a second media stream from the second entity to the first entity without intervention by said call processor. 
     Preferably the media streams are redirected via the call processor, upon receipt, by the call processor, of a message from the second entity the method further comprising the steps of: the call processor sending a message to the first entity to cause media to be transmitted over a third media stream to the call processor, the call processor creating a fourth media stream and forwarding media received from the first entity via the third media stream to the second entity over the fourth media stream such that the call processor may modify the media received from the first entity before forwarding the media to the second entity; and the call processor sending a message to the second entity to cause to cause media to be transmitted over a fifth media stream to the call processor, the call processor creating a sixth media stream and forwarding media received from the second entity via the fifth media stream to the first entity over the sixth media stream such that the call processor may modify the media received from the second entity before forwarding the media to the first entity. 
     In one embodiment the call processor modifies the media received from the first entity by removing sensitive information before forwarding the media stream to the second entity. 
     In another embodiment the call processor modifies the media received from the first entity by removing DTMF tones before forwarding the media stream to the second entity. 
     In a third embodiment the call processor modifies the media received from the first entity by removing spoken sensitive information before forwarding the media stream to the second entity. 
     Preferably the method further comprises the steps of: the contact centre sending a message to a secure data collection centre to indicate secure data collection is to be initiated on a particular media call; the secure data collection centre returning a personal identification number; and in which the message received by the call processor from the second entity contains said personal identification number. 
     Advantageously the media streams are reconnected to bypass the call processor, the method further comprising the steps of the call processor sending a message to the first entity to cause the media to be sent over the first media steam to the second entity; and the call processor sending a message to the second entity to cause media to be sent over the second media stream to the first entity. 
     The first entity may be a user and the second entity may be a contact centre. 
     The media call may be a VoIP call. The signalling streams may be SIP streams. The media stream may be an RTP stream. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an illustration of a call processing environment for use in a system for collection of sensitive information; 
         FIG. 2  is a simplified illustration of call paths when a call is in unsecured mode; 
         FIG. 3  is a simplified illustration of call paths showing a call conferenced with the call processor; 
         FIG. 4  is a simplified illustration of call paths showing removal of sensitive information from a media stream sent to a contact centre; and 
         FIG. 5  is a simplified illustration of call paths showing removal of sensitive information from a media stream sent to a user. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , a call processor  14  is accessed via a firewall  11  (eg AWS), and a Session Border Controller  12  (SBC) (eg AudioCodes or Sonus). The call processor  14  interfaces with a secure data collection environment  16 . 
     A first entity, in the embodiment described here, a user  17  initiates a VoIP call to a second entity, in the embodiment described here, a contact centre  18 . The VoIP call may originate from the PSTN via a trunk provider. When the contact centre&#39;s address is detected in the signalling stream (for example, when during call set up using a SIP INVITE message) the trunk provider redirects the signalling stream to the call processor  14 . 
     When call processor  14  receives a first signalling stream  20  from a user  17  the call processor  14  creates a second signalling stream  21  to the contact centre  18  and forwards any messages received via the first signalling stream  20  from the user to the contact centre  18  via the second signalling stream  21 . Reciprocally the call processor  14  forwards any messages received via a third signalling stream  22  from the contact centre to the user  17  via a fourth signalling stream  23 . The user is unaware that the signalling messages are intercepted and passed on by the call processor  14 . Hence once signalling messages are exchanged to set up a VoIP call between the user  17  and the contact centre  18  the VoIP call is created between the user  17  and the contact centre  18  without intervention by the call processor  14 . Hence, the bandwidth of the data that the call processor  14  needs to process is approximately 5 Kbps×2. As the call processor  14  retains signalling paths to both the user and to the contact centre the call processor  14  has the ability to control the interaction between the user  17  and the contact centre  18 . 
     In more detail, using SIP protocol the call set up process may be as follows: 
     1) SIP INVITE (first call ID) is sent by the user  17  to the call processor  14 . 
     2) SIP INVITE (second call ID) is sent by the call processor  14  to the contact centre  18 . 
     3) SIP OK (second call ID) is sent by the contact centre  18  to the call processor  14 . 
     4) SIP OK (first call ID) is sent by the call processor  14  to the user  17 . 
     5) A first voice media stream  24  (usually using RTP) is created from the user  17  to the contact centre  18 . 
     6) A second voice media stream  25  (usually using RTP) is created from the contact centre  18  to the user  17 . 
       FIG. 2  is a simplified illustration showing the signalling and media streams when the call is in an ‘unsecured’ mode ie when it is not required to transmit sensitive information between the user  14  and the contact centre  17 . 
     When it becomes necessary to transmit sensitive information between the user  17  and the contact centre  18  a request  26 , which may be initiated by an agent in the call centre, is sent to the secure data collection server  16 . The request  16  may be sent via the internet, via a private network or any other suitable means. The request from the contact centre  18  contains a unique identifier (sometimes called a SessionID) that identifies the contact centre agent within the contact centre. The unique identifier may be created (for example) when the contact centre agent logs onto the web interface of the Secure Data Collection  16  system. 
     The Secure Data Collection  16  system generates a Personal Identification Number (PIN) that is sends back to the contact centre agent over the Internet (typically displaying in a web browser). 
     The secure data collection server  16  returns a response  27  containing a unique identifier identifying the signalling streams and the media call in question. 
     The contact centre agent enters the PIN and generates a message requesting that a media call goes into ‘secure mode’ which is sent via signalling stream  22  to the call processor  14 . This message contains the PIN. Call processor  14  liaises with the secure data collection server  16  to confirm that the request is legitimate, for example by comparing the PIN received to those which have been previously been sent out. 
     Assuming the request is legitimate call processor  14  reroutes the media stream so that it is redirected via the call processor. 
     In more detail, using SIP protocol the call rerouting process may be as follows: 
     1) re-INVITE (first call ID) is sent by the call processor  14  to the user  17   
     2) SIP OK (first call ID) is sent by the user to the call processor  14   
     3) re-INVITE (second call ID) is sent by the call processor  14  to the contact centre  18   
     4) SIP OK (second call ID) is sent by the contact centre  18  to the call processor  14 . 
     The call processor  14  then initiates a conference call with the user  17  and the contact centre  18 .  FIG. 3  is a simplified illustration of the resultant signalling and media streams. 
     A third VoIP media stream  30  is created between the user  17  and the call processor  14 . VoIP data is transmitted over the third VoIP media stream  30  to the call processor  14 . The call processor  14  creates a fourth VoIP media stream  31  and forwards VoIP data received from the user  17  via the VoIP third media stream  30  to the contact centre  18  over the VoIP fourth media stream  31 . 
     This will enable the call processor to modify VoIP data received from the user, for example by removing DTMF tones or spoken sensitive information before forwarding the media to the contact centre  18 . 
       FIG. 4  shows schematically sensitive data being removed from the fourth media stream  31  before being forwarded to the contact centre  18 . 
     A fifth VoIP media stream  32  is created between the contact centre  18  and the call processor  14 . VoIP data is transmitted over the fifth VoIP media stream  32  to the call processor  14 . The call processor  14  creates a sixth VoIP media stream  33  and forwards VoIP data received from the contact centre  18  via the VoIP fifth media stream  32  to the user  17  over the VoIP sixth media stream  33 . 
     This will enable the call processor to modify VoIP data received from the contact centre  18 , for example by removing DTMF tones or spoken sensitive information before forwarding the media to the user  17 . 
       FIG. 5  shows schematically sensitive data being removed from the sixth media stream  33  before being forwarded to the user  17 . 
     The call processor  14  liaises with the secure data collection system  16  to obtain the required sensitive data from the user  17  and removes the sensitive data from the media that is forwarded to the contact centre  18 , thus preventing the sensitive information from ever entering the contact centre  18 . 
     The call processor  14  only needs to process the bandwidth required for the media call during the time that the call is in ‘secure’ mode. Once the sensitive data has been collected the media stream can be reconnected directly between the user  17  and the call centre  18  and the call processor  14  will drop out of the media stream. 
     The call is rerouted in a similar manner to previously: 
     1) re-INVITE (first call ID) is sent by the call processor  14  to the user  17   
     2) SIP OK (first call ID) is sent by the user to the call processor  14   
     3) re-INVITE (second call ID) is sent by the call processor  14  to the contact centre  18   
     4) SIP OK (second call ID) is sent by the contact centre  18  to the call processor  14 . 
     The call paths revert to those shown in  FIG. 2 . 
     It will be appreciated that features of the invention which are, for brevity, described in the context of a single embodiment, may also be provided separately, or in another suitable combination. 
     It will be recognised that various alterations, modifications, and/or additions may be introduced into the constructions and arrangements of parts described above whilst remaining within the scope of the invention as claimed.