Apparatus and method for performing hosted and secure identity authentication using biometric voice verification over a digital network medium

Apparatus, methods, and machine-readable articles of manufacture enable a means of performing vocal tract based authentication and vocal tract based enrollment via the Internet or similar computing network as a communication medium. A protocol and process is outlined which enables Internet or similar network based authentication among three parties; a party wishing to prove a claimed identity, a party requesting to authenticate the claimed identity, and a party performing the authentication or enrollment process. Further, the party requesting authentication is a separate entity from the party performing authentication or enrollment. In such an arrangement, the party performing the authentication or enrollment is termed “hosted” or “software as a service”. The protocol and process is suitable for execution by distinct software components installed and running on computers located at the location of each of the three parties.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to computing, biometrics, cryptography and digital networking. More particularly, the invention relates to the use of a digital network as a medium for performing vocal-based biometric identification on behalf of another party requesting identity verification, utilizing cryptographic techniques to protect information as it is transferred over the digital network.

2. Discussion of Related Art

With the explosion of the Internet in recent years, more and more companies are hosting web sites that allow a client to log into their accounts via those websites by typing a password entered at a computer terminal. Many of these accounts are banking and financial based. Since a text password can easily be compromised, in order to prevent theft and fraud, alternate means of identification are needed. In general, biometric verification is a useful means of proving claimed identity. However, it can be argued that certain types of biometrics, such as retinal scans and thumbprint scans are only useful if the person to be verified is physically present at the location of the challenging party or entity requesting authentication. Vocal tract based biometric verification is however distinctly different from the static measurement of say a retinal scan or thumbprint scan, in that it is a dynamically produced measurement, whereby the information used to verify identity can be distinctly different each time a proof of identity is required. For example, the challenging party formulates a new random challenge phrase each time authentication is needed. This challenge phrase must then be recited or spoken to the challenging party in exact order by an individual desiring to prove their identity.

Vocal tract based biometric verification generally includes two phases; an enrollment phase and a verification phase. During enrollment, a speech processor running on a computer is used to segment spoken phrases in audio form into feature vectors. Next, these feature vectors are fed into a data classification engine, which produces a unique voiceprint, or model of an individual's voice. During the verification phase, an enrolled individual's voiceprint is loaded into the data classification engine. The individual who desires to be verified is prompted to speak one or more randomly chosen phrases via a Text-to-Speech (TTS) component. These phrases are digitally captured by a microphone attached to a computer, and are first identified for correctness, by providing them as input to an Automatic Speech Recognizer (ASR). The ASR determines if the phrase spoken matches the challenge phrase in terms of human understandability. For example if the challenge phrase is “one two three four”, and the individual speaks “four three two one”, this first test fails. Secondly, the phrases are again fed as input through a speech processor which produces feature vectors. These feature vectors are then fed as input into the data classification engine, which compares the data model produced to the previous voiceprint. Based on certain criteria specific to the verification algorithm, the identity verification is either accepted or rejected.

SUMMARY OF THE INVENTION

A general object of the invention is to provide an apparatus, method and article of manufacture for performing a vocal-based biometric authentication or enrollment process over the internet in a hosted fashion or a Service Oriented Architecture (SOA) model.

Another object of the present invention is to perform the authentication or enrollment process in such a fashion as to be cryptographically secure, given the fact the Internet is an open, public network. Due to the present popularity of mobile Internet use, a need also exists to perform the authentication or enrollment process without restricting the end user, who is an individual desiring to be vocally authenticated or enrolled, to a static or fixed location on the Internet at time of verification.

Embodiments of the present invention are directed to methods, apparatus, and articles of manufacture that satisfy one or more of these needs. In some embodiments, the invention herein disclosed is a method of performing vocal-tract based authentication via a packet switched network, such as Transmission Control Protocol/Internet Protocol (TCP/IP) based networks, wherein a communication protocol is used among three parties at hand; a user operating a terminal, an institution, and a verification service. Each party is preferably located at a distinct location with respect to Internet addresses.

According to this method, the user operating the terminal, where the terminal possibly includes a computer equipped with a web browser, soundcard (or similar on-board device capable of digital-to-analog audio conversion, and analog-to-digital audio conversion), speaker, microphone, and/or other software capable of communicating via the communication protocol establishes a first connection to software executing at the institution. This first connection can be a Hyper Text Transfer Protocol (HTTP) or similar network connection. At some time later, the user claims a particular identity, which is transmitted by the first connection to the institution. This first connection may be secured by a secured socket layer (SSL) protocol or similar, with at least the institution providing proof of identity. Proof of identity may be accomplished with, for example, a X509 certificate.

The institution then initiates the next step of the protocol process by establishing a second connection to software executing at the verification service. The second connection may be secured by an SSL protocol or similar. Further certificates, such as X509 certificates, may be utilized to provide proof of identity on the institution end and the verification service end of the connection. Within the second connection, a session is established for vocal enrollment and/or vocal authentication.

For vocal authentication, the institution provides a first identifier, for the institution, and a second identifier, for the user operating the terminal, to the verification service. In return the verification service sends a session identifier to the institution, along with a first binary string, a secret key, representing pending success of the authentication process. A file is then generated within an Extensible Markup Language (XML) or similar format by the institution, which is subsequently transmitted to the terminal via the first connection. This file contains specific information regarding the session identifier previously established, as well as an address that the software of the terminal may use to interact with the verification service. When the XML file is transmitted to the terminal from the institution, it is associated with a new Multipurpose Internet Mail Extension (MIME) specific for the purpose of vocal authentication. The web browser of the terminal is preconfigured to launch a previously installed software component on the computer of the terminal, when an object of this MIME type is received. As the next stage of the protocol, this previously installed software component establishes a third connection to the verification service. The third connection transmits a Simple Object Access Protocol (SOAP) or a HTTP request or similar to start the authentication process and may be encrypted via SSL with X509 or similar method. For this third connection, only the verification service preferably provides an X509 certificate. The third connection preferably provides a control layer, an audio transmission layer from the verification service and an audio transmission layer from the terminal. In an alternative embodiment this third connection between the terminal and the verification service may comprise a plurality of separate connections for each of the layers or combinations of the layers. The control layer relays the state of the authentication system. In this embodiment, the authentication system state is determined by the verification service.

The vocal-based biometric authentication further includes a cycle of challenge and response exchanges. To begin, a challenge, for example, a random prompt, is sent in human comprehensible audio form from the verification service to the computer of the terminal via the audio transmission layer from the verification service and is rendered via the soundcard and speakers installed in the computer of the terminal. In response to the challenge, the user responds vocally to the challenge and is recorded via a microphone attached to the computer of the terminal. This recording, a voice print, is transmitted, preferably in encrypted form, to the verification service via the audio transmission layer from the terminal. The cycle of challenge and response may repeat one or more times if the vocal data analyzed by the verification service does not initially match both the challenge phrase and a pre-existing voiceprint associated with the identity claimed by the user operating the terminal. When the challenge and response cycle has ended, a second binary string is transmitted via the third connection, the control layer, from the verification service to the previously installed software component on the computer of the terminal. Next, the previously installed software component on the computer of the terminal completes the protocol by relaying the second binary string to the institution via the first connection. The software service running on the institution determines the authentication result by comparing the first binary string to the second binary string. If the first binary string and the second binary string are identical, then the user operating the terminal is successfully authenticated. If the first binary string and the second binary string are not identical then the authentication fails.

In an alternate embodiment the previously described procedure can also be applied to vocal enrollment, which is a prerequisite to vocal authentication. Yet, in further alternate embodiments, other forms of biometric based authentication, apart from vocal tract based biometric authentication and including retinal scans and fingerprint identification, may be substituted or incorporated into the apparatus and method provided by this invention. Alternate embodiments may use other apparatus apart from a web browser to initiate the authentication process.

DESCRIPTION OF PREFERRED EMBODIMENTS

The invention herein disclosed can be implemented in an open digital network of heterogeneous computers, such as the Internet. The invention is inherently designed to provide a biometric voice verification on behalf of a first party wishing to be authenticated, a second party wishing to authenticate and a third party providing authentication services. The framework of the invention provides for multiple parties to interact simultaneously. Each party is preferably, though not necessarily, located at a separate location on the network. The first party wishing to authenticate optionally may be located on a separate network, partitioned behind a firewall. The firewall is a computing device residing on two or more networks, which permits computing devices located on a separate, generally smaller network, access to a greater network. At each location, a computing device is present which executes code instructions comprising the process and articles of manufacture of the invention. A code may be loaded into the memory of the computing device from a machine-readable medium, such as a CD, a DVD, a flash memory, a floppy or a hard drive, or a similar memory or storage device.

Reference will now be made in detail to several embodiments of the invention that are illustrated in the accompanying drawings. The drawings are in simplified form, not to scale, and omit apparatus elements and method steps that can be added to the described systems and methods, while including certain optional elements and steps.

FIG. 1illustrates a block diagram10of entities involved in a “hosted” service based speaker authentication framework in accordance with an embodiment of the present invention. The hosted service based speaker authentication framework includes three primary entities: a verification service20; an institution40; and a terminal60. The verification service20includes a user verification web service22, an institution verification web service24and an ASR/TTS/verification subsystem26. According to a preferred embodiment of the invention, the institution40includes a web server42, an authentication servlet44and an institution web service46. The authentication servlet44is preferably written in java, however, the authentication servlet44may be written in any language. The terminal60preferably includes a computer62, a web browser64, a soundcard66, a speaker68, a microphone70and an identifier application72. A certificate entity80is a software service, pertinent to the present embodiment making use of Secure Socket Layer (SSL) which provides authentication between software services running on the institution40and the verification service20. All connections between the three primary entities—the verification service20, the institution40and the terminal60—are preferably TCP/IP based connections and bi-directional. A digitally signed certificate of the verification service28is present to validate authentication of the user verification web service22and the institution verification web service24running on the verification service20. Also, a digitally signed certificate of the institution48is present to validate authentication of the web server42, the authentication servlet44and the institution web service46running on the institution40respectively.

Referring toFIG. 2, a sequence diagram100, the interactions of the entities shown inFIG. 1are illustrated, for the purpose of displaying a process for vocal enrollment or vocal authentication according to one preferred embodiment of the invention. It should be noted that the connections and messages in all three figures are similar, and all three figures apply to both enrollment and authentication interactions.FIG. 2shows connections and messages sent between the various entities within the scope of a particular embodiment of the invention.

As shown inFIG. 2, a first connection102is established between the web browser64and the web server42, which is encrypted via SSL and the authentication of the web server42is validated via the digitally signed certificate of the institution48. The digitally signed certificate of the institution48is provided from the web server42to the web browser64via the first connection102to ensure authentication of the institution40to the terminal60. A first message104is transmitted via the first connection102, from the terminal60to the institution40, which claims an identity.

Typically, a user operating the terminal60claims the identity via a method of identification such as a user-name and a password, to establish a session. The state of the session is preferably managed by the code running within the web server42and the authentication servlet44. When the user operating the terminal60decides to request execution of a transaction, it sends a transaction message106from the web browser64to the web server42, within the context of the session. In sequence, the web server42communicates to the authentication servlet44, a software component running within the institution40computer(s) which provides backend logic for serving dynamic web pages. A pre-existing connection108is assumed between the web server42and the authentication servlet44, alternatively, both the web server42and the authentication servlet44may exist within the same binary executable image, executing at the institution40.

The authentication servlet44next establishes a second connection110, from the authentication servlet44to the institution verification web service24. The second connection110is preferably secured via SSL with client and server side certificates, the digitally signed certificate of the verification service28and the digitally signed certificate of the institution48. Via the second connection110, a second message112is sent from the authentication servlet44to the institution verification web service24to request establishment of a session between the institution40and the verification service20for vocal enrollment into the system, or to validate the claimed identity. One purpose of the second message112depends on the purpose of the transaction message106, namely vocal enrollment or vocal authentication, but may include a secret key, a large binary string that will provide authentication of the user operating the terminal60.

In order to establish the session between the institution40and the verification service20, the institution40provides the second message112from the authentication servlet44to the institution verification web service24wherein, preferably, at least two pieces of information are specified: an account ID for the institution40and a user ID for the user operating the terminal60to be authenticated or enrolled. If credentials match, the session between the institution40and the verification service20is created within the context of the verification service20, and a third message114containing pertinent information is transmitted via the second connection110. A fourth message116is then transmitted via the web server42and the first connection102to the web browser64, which in turn launches the identifier application72. The fourth message116may take the form of a particular Multipurpose Internet Mail Extension (MIME) type, which can be pre-registered with the web browser64to trigger launch of the identifier application72. The fourth message116preferably contains data, which is fed into the identifier application after its launch. Among the items in the data of fourth message116are the location of the verification service20and a session identifier created for authenticating the particular user. Next, the web browser64waits for a current web page to change by polling for refreshes, or alternatively, by using other common web technologies, such as AJAX/JavaScript, to provide notification when the authentication session is complete.

Again referring toFIG. 2, the identifier application72establishes a third connection118to user verification web service22. This third connection118is secured via SSL and the digitally signed certificate of the verification service28. The identifier application72sends a fifth message120to the user verification web service22to begin the vocal authentication process. The fifth message120preferably contains at least the session identifier, which is temporarily valid, and establishes the start of the vocal authentication procedure. The identifier application72then establishes a fourth connection122and a fifth connection124, which are of a different type, and set up a recording audio path through the fourth connection122and a playing audio path through the fifth connection124. Each connection122,124is encrypted, via SSL or similar. The third message114, provided from the verification service20, presents the session identifier to the institution40. And, the fifth message120, provided from the institution40, presents the session identifier to the verification service20. A cycle is then entered, where, in one preferred embodiment:1) The verification service20generates an audio-based prompt126via the ASR/TTS/verification subsystem26. The audio-based prompt126is then transmitted within a sixth message128to the identifier application72via the fourth connection122in encrypted form. The identifier application72then renders this audio to the user of the terminal60via the soundcard66and the speaker68.2) The user repeats the prompt126into the microphone70and the identifier application72records. Generating audio data which is sent within a seventh message130to the verification service20via the fifth connection124.3) The verification service20sends the audio data to the ASR/TTS/verification subsystem26for analysis via an eighth message132. The ASR/TTS/verification subsystem26converts the audio data into a voice print. Then:a) If the present mode of operation is authentication, the analysis is focused on matching the voiceprint to a pre-existing voiceprint of the user within a predetermined confidence quantity.b) Alternatively, if the present mode of operation is enrollment, producing the pre-existing voiceprint, or training, the analysis is focused on ensuring that the audio data contains the correct human speech, again within the predetermined confidence quantity, that was prompted in cycle step1for the user to speak in step2.4) If the analysis in step3satisfies the predetermined confidence quality constraints mentioned in step3, then the cycle ends. Otherwise step1is resumed. If the cycle repeats a predetermined or actively determined maximum quantity of times, then the cycle ends. For example, in certain embodiments the maximum times the cycle may repeat is three. However, in another embodiment, the maximum times the cycle may repeat is five. Yet, in another embodiment the cycle count may be determined based on confidence values observed in step3of the cycle. A ninth message134queries the verification service20to determine if the cycle is due to repeat.

Referring toFIG. 2, a tenth message136is sent from the verification service20to the identifier application72. This tenth message136contains a large binary string, which denotes either failure or success of the authentication. The tenth message136is sent via the encrypted third connection118. Next, the identifier application72establishes a sixth connection138to the institution web service46, again encrypted via SSL or similar. Authentication of the institution40to the identifier application72, is performed in the SSL layer, utilizing certificate digitally signed certificate of the institution48. Via the sixth connection138, the identifier app sends an eleventh message140to the institution web service46. The eleventh message140, at a minimum, preferably contains the resultant large binary string and the session ID for this particular authentication or voice print training session. At this point in the process, the role of the web service46is to update internal data of the institution40, regarding whether or not the authentication or voiceprint training session succeeded, and secondly to cause a web page on the computer62to refresh for the user of terminal60. At this point in time, the institution40now has the result of the authentication session, and can allow/disallow the original user-requested transaction to proceed.

Referring toFIG. 3, a diagram200of the interactions of the entities are shown from the viewpoint of state changes, as the various components change state throughout the operation of a preferred process. InFIG. 3, the mode of operation presented is authentication, which assumes that the user has established the pre-existing voiceprint via the verification service20.

Referring toFIG. 3, in step one202, the user first establishes the session between the terminal60and the web server42, and claims the identity in step two204. In step three206, the session is then created between the institution40and the verification service20and the secret key is created by the verification service20and sent to the institution40. In step four208, the identifier application72is launched. Then, in step five210, the session between the terminal60and the verification service20is created. In step six212, the recognition cycle begins. After prompting by the verification service20, step seven214, the voiceprint of the user is provided to the verification service in step eight216, the verification service20uses speech recognition and speech verification engines to compare the voiceprint of the user with the pre-existing voiceprint to determine if the user of terminal60matches their claimed identity, decision218. If the voiceprint provided by the user of terminal60is either misrecognized or does not match the pre-existing voiceprint, then the recognition cycle, step seven214and step eight216, may be repeated, arrow220. A non-arbitrarily chosen limit may be placed on the number of times the recognition cycle may repeat, arrow222and the verification service20determines an imposter, step nine(a)224. If the user's speech was correctly spoken and the voiceprint matched the existing voiceprint, step nine(b)226, then a valid binary string is selected, step ten(b)228, and is presented to the identifier application72, step eleven232. Otherwise, if the user's voiceprint did not match the pre-existing voiceprint, then an invalid binary string is selected, step ten(a)230, and provided to the identifier application72, step eleven232. The identifier application72has no, way of determining whether or not the binary string is valid or not, since the valid binary string, denoting successful authentication, is a shared secret between the verification service20and the institution40. The identifier application72then presents the binary string it received from the verification service to the institution40, step twelve234. The institution40in turn, compares the binary string to the shared secret key, decision236. If the two binary strings match, then the user of terminal60has successfully authenticated, result238. Otherwise, if the binary string presented by the identifier application72does not match the shared secret key, the user of terminal60has not successfully authenticated, circle240.

According to one preferred embodiment of this invention, as shown inFIG. 4, the identifier application72is replaced by a telephony-identifier50and a telephone74. The telephony-identifier50is preferably hosted by the institution40, though not necessarily physically located at the institution40. As such, the telephony-identifier50need only have network access to the institution40. For the user to perform the vocal authentication or vocal enrollment in this alternative embodiment, the user connects to the telephony-identifier50through the telephone74. The telephony-identifier50then establishes an encrypted connection with the user verification web service22.

The embodiments described are useful for performing vocal based speaker authentication over the Internet; however the protocol and method of the present invention may be used for performing authentication of other forms including retinal scans and fingerprint identification. By substituting an addition to or a replacement of the ASR/TTS/verification subsystem26with another type of authentication engine, and by replacing or adding to the speaker68with another medium of instruction or challenge and by replacing or adding to the microphone70for capturing input other forms of authentication may use the presented process for performing authentication.