Patent Publication Number: US-11645372-B2

Title: Multifactor handwritten signature verification

Description:
BACKGROUND 
     The present disclosure relates to signature verification and, more specifically, to handwritten signature verification based on a predictive model. 
     Handwritten signatures are used for authentication in various applications, such as on documents related to purchases, agreements, and authorizations. In some instances, signatures are accompanied by additional forms of identification, such as face and/or voice recognition. A signature can be compared to an earlier example of an individual&#39;s signature in order to determine whether the signature is authentic. The comparison can be carried out automatically (e.g., via image recognition and similarity algorithms) or by human handwriting experts. 
     SUMMARY 
     Various embodiments are directed to a system that includes at least one processing component, at least one memory component, and a reference storage comprising a set of reference signatures. The system also includes a model generator configured to generate a signature model based on the set of reference signatures. Further, the system includes a verification component configured to receive a signature, and determine whether the signature is valid. The verification component can determine that the signature is valid. The model generator can also update the signature model if it is determined that the signature is valid. The model generator can also reject the signature, and optionally update the signature model with the rejected signature, if the signature is determined not to be valid. The model generator can also generate a secondary model based on a set of reference secondary identifying information. The verification component can generate a signature progression score for the signature, and a secondary progression score for secondary identifying information. The verification component can then determine that the signature progression score and secondary progression score are consistent. Additionally, the verification component can determine that the signature progression score and secondary progression score are not consistent, reject the signature, and optionally update the set of reference signatures to include the rejected signature. In some embodiments, the signature model is a progression model. 
     Further embodiments are directed to a method that includes generating a signature model based on a set of reference signatures, receiving a signature, and determining whether the signature is valid. The method can also include determining that the signature is valid, and updating the signature model in response. The method can also include generating a secondary model based on a set of reference secondary identifying information, generating a signature progression score for the signature, and generating a secondary progression score for secondary identifying information. The method can also include determining that the signature progression score and secondary progression score are consistent. It can also be determined that the signature progression score and secondary progression score are inconsistent, the signature can be rejected, and the set of reference signatures can be updated to include the rejected signature. The signature model can be a progression model. 
     Additional embodiments are directed to a computer program product that includes a computer readable storage medium having program instructions that are executable by a processor to cause a device to perform a method that includes generating a signature model based on a set of reference signatures, receiving a signature, and determining whether the signature is valid. The method can also include determining that the signature is valid, and generating a secondary model based on a set of reference secondary identifying information, generating a signature progression score for the signature, and generating a secondary progression score for secondary identifying information. The method can also include determining that the signature progression score and secondary progression score are consistent. It can also be determined that the signature progression score and secondary progression score are inconsistent, and the signature can be rejected. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a block diagram illustrating a signature verification environment, according to some embodiments of the present disclosure. 
         FIG.  2    is a flow diagram illustrating a process of verifying a signature, according to some embodiments of the present disclosure. 
         FIG.  3    is a block diagram illustrating a computer system, according to some embodiments of the present disclosure. 
         FIG.  4    is a block diagram illustrating a cloud computing environment, according to some embodiments of the present disclosure. 
         FIG.  5    is a block diagram illustrating a set of functional abstraction model layers provided by the cloud computing environment, according to some embodiments of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Handwritten signatures are used in a variety of contexts. For example, documents related to purchases, agreements, and authorizations; ballots; identification (ID) and/or credit cards; cheques; artwork; etc. are frequently hand-signed. Because these signatures are hand-signed, there can be variations between different copies of a signature written by the same person. However, it can be necessary to compare copies of the signature (e.g., automatically via image recognition and similarity measuring algorithms) in order to determine the veracity of a particular copy (e.g., to identify a forged signature). When current signature verification techniques are used for these comparisons, the signatures can be incorrectly identified due to variations caused by aging and/or health conditions that can affect a signing individual&#39;s movements and, thereby, handwriting. Thus, genuine signatures can be falsely identified as forgeries when they are compared to a static model based on an earlier version of an individual&#39;s signature. Similarly, forgeries can be falsely identified as genuine signatures despite mimicking only earlier versions of an individual&#39;s signature. 
     Disclosed herein are techniques for analyzing signatures while taking into account variations in individuals&#39; handwriting over time. Timestamped reference signatures for a signing individual are gathered, and used to generate a model. This model can determine how a signature changes over time relative to the reference signatures. In some embodiments, the model simulates future versions of the signature. When the individual provides a signature, the signature is compared to the signature model to calculate a likelihood of the signature being authentic. 
     Models can also be generated based on other reference identifying information that is age-dependent, such as facial appearance, voice, etc. These models can be used to validate the signature model and/or confirm the identity of the signing individual. It should be noted that, while the techniques disclosed herein are discussed in the context of signature verification, the techniques can have various applications. For example, progressive models can be generated for handwriting samples other than signatures, hand-drawn images, etc. 
       FIG.  1    is a block diagram illustrating a signature verification environment  100 , according to some embodiments of the present disclosure. The signature verification environment  100  includes a signature  110  and, optionally, secondary identifying information  115  provided by a signing individual, an authentication module  120 , and a reference storage  125 . The reference storage  125  contains a set of timestamped reference signatures  130  written by the signing individual and a signature model  135  for comparison to the signature  110 . The reference storage  125  can also include a set of reference secondary identifying information  136  and a secondary model  137 . 
     The signature model  135  is generated by a model generator  140  in the authentication module  120 , and is based on the reference signatures  130 . The authentication module  120  also includes a verification component  150  for verifying the signature  110  based on the signature model  135 . In some embodiments, the signature model  135  is a progression model. However, the signature  135  can also be a generative model. Types of signature models  135  are discussed in greater detail below. The model generator  140  can also generate the secondary model  137  based on the reference secondary identifying information  137 . In embodiments, the model generator  140  and the verification component  150  can be processor executable instructions that can be executed by a dedicated or shared processor using received inputs. 
     The signature  110  and reference signatures  130  are provided in a computer-readable format (e.g., as a digital photographic image). For example, a signed document can be photographed or scanned to produce a JPEG file, PDF file, etc. A user can optionally select the signature  110  in the document image using cursor movements in a user interface. In some embodiments, the signature  110  is automatically extracted from an image of a signed document using image recognition techniques known to persons of ordinary skill in the art. The signature can also be automatically located based on the document field it is in, such as a field located in a particular position on the document (e.g., the bottom right corner) and/or labeled “signature”. In other embodiments, the signature  110  can be entered directly via a user interface. For example, an individual can sign on a touchscreen using a finger or stylus. Additional direct signing techniques can include cursor movements, hand gestures (e.g., in an augmented reality user interface), etc. The techniques used to obtain the signature  110  can also be used to obtain the reference signatures  130 . The images of the signature  110  and each reference signature  130  can be processed using techniques such as gray conversion, noise reduction, edge enhancement, binarization, etc. These techniques are used to extract features such as width, height, aspect ratio, etc. from the signatures  110  and  130 . 
     The reference storage  125  can be in the memory of a computing device such as a personal computer or a server (see, e.g.,  FIG.  3   ) and/or a blockchain configuration. For example, reference data such as the reference signatures  130  and associated extracted features can be stored in the blockchain as a record for the signing individual, along with logs of ongoing verification steps. The time, date, and context of each reference signature can be documented in the reference storage  125  as well. In some embodiments, a snapshot of selected reference data can be stored in the blockchain, based on risk analysis, to create the record. The reference signatures  130  can be updated when a current signature  110  is analyzed and added to the reference storage  125 . This is discussed in greater detail with respect to  FIG.  2   . 
     The reference signatures  130  can be input by the signing individual (e.g., by signing at various intervals and/or providing previously signed documents) or another person who has access to documents signed by the signing individual. The reference signatures  130  can also be gathered automatically by the model generator  140 . For example, reference signatures  130  can be obtained from a set of computer-readable images of signed documents (e.g., receipts) stored in a database. 
     In addition to reference signatures  130 , the reference storage  125  can include reference secondary identifying information  136  such as sets of facial images (e.g., timestamped graphical images of the signing individual&#39;s face), voice recordings (e.g., timestamped audio recordings of the signing individual&#39;s voice), context information regarding the signing individual (e.g., name, age, health and/or demographic information, etc.), etc. The reference storage  125  can also include a secondary model  137  associated with each type of secondary identifying  115  information. Secondary model  137  examples are discussed in greater detail below. Further, the reference storage  125  can include verified modality of signature templates, such as associated workflows for a signature template (e.g., for creating, storing, or changing signatures). 
     Additional identifying information stored in the reference storage  125  can include biometric data (e.g., fingerprints and/or iris scans), copies of identifying documents (e.g., a birth certificate, passport, government ID, etc.) and/or associated information (e.g., name, date of birth, government ID number, etc.), records of the amount of time taken to write a signature, etc. Context information for signed documents associated with the reference signatures  130  can be stored as well. This information can include sensitivity scores (e.g., measures of document importance) and/or document categories (e.g., government documents, payment agreements, employment contracts, ballots, etc.). 
     The model generator  140  generates a signature model  135  based on the reference signatures  130 . This model  135  is based on observed variations in the timestamped reference signatures  130 , and predicts how features of the signing individual&#39;s handwritten signature will change over time. The model&#39;s  135  prediction can also take into account other factors that may affect how the signature  110  will appear at a given time based on, for example, health conditions that can affect mobility and handwriting (e.g., Parkinson&#39;s disease, Alzheimer&#39;s disease, etc.). In some embodiments, the signature model  135  is a progression model. For example, the signature model  135  can be generated with a recurrent neural network (RNN) such as a long short-term memory (LSTM). However, any appropriate modeling techniques can be used. For example, the signature model  135  can be a generative model generated using, e.g., Hidden Markov Models or Naïve Bayes models. 
     Using techniques such as those used to generate the signature model  135 , the model generator  140  can generate at least one secondary model  137  based on the reference secondary identifying information  136 . For example, a secondary model  137  can be based on variations in timestamped facial images. In some embodiments, the secondary model  137  incorporates factors such as health conditions, demographic information, and/or environmental factors that can affect the progression of secondary identifying information  115 . For example, a secondary model  137  based on facial images can take into account predicted sun exposure based on the geographical location of the signing individual&#39;s residence. 
     The verification component  150  compares the signature  110  to the signature model  135 , and determines whether the signature  110  is valid. When the signature model  135  is a generative model, the verification component  150  determines that the signature  110  is valid if the signature  110  has a similarity to a signature generated by the model  135  that is greater than a similarity threshold (e.g., 80%, 90%, 95%, etc.). When the signature model  135  is a progression model, the verification component  150  determines whether the signature  110  is a valid signature in the sequence of reference signatures  130  consisting with aging. 
     Further, when the signature  110  has been validated, a signature progression score based on the degree of change in the signature  110  relative to the reference signatures  130  can also be generated. For example, a signature progression score can be a number of years (e.g., five years, fifteen years, thirty years, etc.) assumed to have elapsed based on a degree of change in current signature  110  relative to the reference signatures  130 . A secondary progression score can also be generated based on a comparison between the current secondary identifying information  115  and the secondary model  137 . For example, the secondary progression score can be a number of years assumed to have elapsed based on a degree of change in the current secondary identifying information  115  relative to the reference secondary identifying information  136 . For example, a secondary progression score can be based on a comparison of a current facial image to a secondary model  137  based on reference facial images. 
     The verification component  150  can determine the probability of a progression score being correct based on the confidence of the associated progression model  135  or  137 . For example, if the signature model  135  generates a progression score of five years with a confidence value of 0.8, the verification component  150  can determine that there is an 80% probability of the score being accurate. The progression score and probability can then be used to further verify the signature  110  based on the consistency between the signature progression score and a secondary progression score, weighted by their respective probabilities. 
     For example, the signature progression score can be five years with a probability of 80%, and the secondary progression score can be thirty years with a probability of 30%. Five years can then be selected as the progression score because of its higher probability. For example, five years can have a probability (80%) greater than a probability threshold (e.g., 75%), while thirty years can have a probability (30%) lower than the probability threshold. The authenticity of the validated signature  110  can then be confirmed because the secondary identifying information  115  does not produce a conflicting score having a high enough confidence value to be inconsistent. In another example, the signature progression score (five years) and secondary progression score (thirty years) can each have probabilities of 90%. Therefore, the signature progression score would not be consistent with the secondary progression score, resulting in rejection of the signature  110 . 
     In another example, the signature  110  can be accompanied by signatures of witnesses. The verification component  150  can verify the witness signatures using signature models and/or secondary models for the witnesses, if available. The signature  110  may be accepted as authentic only if the witness signatures are also accepted. Whether or not the signature  110  is accepted can also be based on a document sensitivity score. The sensitivity score can be automatically set or selected by a user (e.g., the originator or signer of the document) based on factors such as the category and/or importance of the document. For example, a government document can have a higher sensitivity score than a receipt for a retail purchase. There can be a sensitivity score threshold associated with a document. If the sensitivity score for the signed document is above a threshold sensitivity score, the verification component  150  can automatically raise the similarity threshold and/or the probability threshold for the signature  110  and, optionally, secondary identifying information  115 . 
     The verification component  150  can add the signature  110  and any received secondary identifying information  115  (e.g., voice recordings, facial images, etc.) to the reference signatures  130  and reference secondary identifying information  136 , respectively. The updated reference information  130  and/or  136  can then be used to retrain the signature model  135  and/or the secondary model  137 . In some embodiments, the signature  110  is added to the reference signatures  130  only when it has been accepted as authentic. However, rejected signatures can be stored as well (e.g., as negative examples) in other embodiments. Additional information that can be stored can include confidence values for progression scores, probability threshold values, sensitivity threshold values, etc. Model updates can also be made based on non-signature information such as location, time, demographic information, etc. periodically added to the reference storage  125 . 
       FIG.  2    is a flow diagram illustrating a process  200  of verifying a signature, according to some embodiments of the present disclosure. To illustrate process  200 , but not to limit embodiments,  FIG.  2    is described within the context of the signature verification environment  100  of  FIG.  1   . Where elements shown in  FIG.  2    are identical to elements shown in  FIG.  1   , the same reference numbers are used in both Figures. 
     A signature  110  is received by the authentication module  120 . This is illustrated at step  210 . The signature  110  can be a handwritten signature from a document in a computer-readable format (e.g., extracted from a graphical image of the document). The signature  110  can also be entered directly into a user interface by the signing individual (e.g., via a touchscreen) in some embodiments. The signature  110  is processed in order to extract its features. This is discussed in greater detail with respect to  FIG.  1   . In some embodiments, other identifying information from the signing individual is received at step  210  as well. For example, the authentication module  120  can receive a voice recording, facial image, fingerprint, government-issued ID, iris scan, etc. from the signing individual. 
     It is then determined whether the signature  110  is valid based on a signature model  135 . This is illustrated at step  220 . The signature model  135  is generated by the model generator  140  (e.g., using deep learning techniques) based on a series of reference signatures  130  stored in the reference storage  125  (e.g., in a blockchain database). In some embodiments, the verification component  150  determines whether the signature  110  is authentic using a signature model  135  based on a sequence neural network (e.g., LSTM) that has learned the progression of how the signature evolves over time based on timestamped signature training data (e.g., the reference signatures  130 ). The signature model  135  takes as input the sequence of reference signatures  130  and the entered signature  110 , and determines whether the signature  110  is a valid progression of the reference signature  130  sequence. If the signature model  135  indicates that the signature  110  is a valid progression, the signature  110  is determined to be valid. In other embodiments, the signature model  135  can be a generative model, and the signature  110  can be identified as valid if the signature  110  and a signature generated by the model have a similarity greater than a threshold similarity. The threshold similarity can be raised if the signed document has a sensitivity score that is above a sensitivity score threshold. 
     If the signature  110  is determined not to be valid based on the signature model  135 , the signature  110  is rejected. This is illustrated at step  230 . When the verification component  150  rejects the signature  110 , the signature  110  and/or signed document can be tagged as possible forgeries. A notification can also be generated to indicate that a potential forgery has been detected. The notification can optionally be sent to a user (e.g., via email or a generated report). In some embodiments, the notification can prompt the user to enter a second signature, or to obtain a different type of validation. For example, a person can check a photo ID belonging to the signing individual. When the signature  110  has been rejected, process  200  can end. However, in some embodiments, process  200  can instead proceed to step  260  (see below), whereupon the rejected signature  110  is added to the reference signatures  130 , and used as a negative example when the signature model  135  is retrained. 
     However, if the signature  110  is determined to be valid based on the signature model  135 , an additional consistency verification is carried out to confirm the authenticity the signature  110 . This is illustrated at step  240 . The verification component  150  produces a progression score and probability for the signature  110 . The verification component  150  also produces a progression score and probability for provided secondary identifying information  115  (e.g., voice samples, facial images, etc.). This information  115  can be provided by the signing individual at step  210  or step  240 . The progression scores are degrees of change observed in the current signature  110  and secondary identifying information  115  relative to the reference signatures  130  and reference secondary identifying information  136 , respectively. The probabilities for each progression score are based on the confidence of the respective models  135  and  137 . For example, the signature progression score can be one year with a probability of 75%, and the secondary progression score can be ten years with a probability of 10%. 
     It is then determined whether the signature progression score is consistent with the secondary progression score. This is illustrated at step  250 . The progression scores are weighted based on their probabilities, and the consistency between the weighted progression scores is determined. This is discussed in greater detail with respect to  FIG.  1   . If the progression scores are determined to be inconsistent, process  200  proceeds to step  230 , whereupon the signature  110  is rejected. 
     However, if the progression scores are determined to be consistent, the signature  110  is accepted, and the signature model  135  is updated. This is illustrated at step  260 . The verification component  150  adds the accepted signature  110  and associated timestamp to the set of reference signatures  130  in the reference storage  125 . In some embodiments, a notification or label is generated to indicate that the signature  110  is accepted. In other embodiments, no notification is generated, but the signature  110  and/or signed document can be tagged as authentic. The verification component  150  can also add the secondary identifying information  115  to the reference secondary identifying information  136 , and the associated secondary model  137  can be updated. 
     The model generator  140  retrains the signature model  135  based on the updated reference signatures  130 . The model generator  140  can also retrain the secondary model  137  based on the updated reference secondary identifying information  136 . Techniques for retraining the models  135  and  137  can include principal component analysis, singular value decomposition, deep learning, LSTM-based sequence learning, etc. In some embodiments, the retraining occurs only when the signature  110  has been validated and/or confirmed. For example, validation of the signature  110  can trigger access to and analysis of the reference signatures  130 , reference secondary identifying information  136 , and any other information in a blockchain reference storage  125 . 
     When the signature  110  is accepted at step  260  and the signature model  135  and, optionally, the secondary model  137  have been updated, process  200  ends. It should be noted that, in some embodiments, step  250  can be omitted from process  200 . In these instances, the signature  110  can be accepted when it is determined at step  220  that the signature  110  is valid. 
       FIG.  3    is a block diagram illustrating an exemplary computer system  300  that can be used in implementing one or more of the methods, tools, components, and any related functions described herein (e.g., using one or more processor circuits or computer processors of the computer). In some embodiments, the major components of the computer system  300  comprise one or more processors  302 , a memory subsystem  304 , a terminal interface  312 , a storage interface  316 , an input/output device interface  314 , and a network interface  318 , all of which can be communicatively coupled, directly or indirectly, for inter-component communication via a memory bus  303 , an input/output bus  308 , bus interface unit  307 , and an input/output bus interface unit  310 . 
     The computer system  300  contains one or more general-purpose programmable central processing units (CPUs)  302 - 1 ,  302 - 2 , and  302 -N, herein collectively referred to as the CPU  302 . In some embodiments, the computer system  300  contains multiple processors typical of a relatively large system; however, in other embodiments the computer system  300  can alternatively be a single CPU system. Each CPU  302  may execute instructions stored in the memory subsystem  304  and can include one or more levels of on-board cache. 
     The memory  304  can include a random-access semiconductor memory, storage device, or storage medium (either volatile or non-volatile) for storing or encoding data and programs. In some embodiments, the memory  304  represents the entire virtual memory of the computer system  300 , and may also include the virtual memory of other computer systems coupled to the computer system  300  or connected via a network. The memory  304  is conceptually a single monolithic entity, but in other embodiments the memory  304  is a more complex arrangement, such as a hierarchy of caches and other memory devices. For example, memory may exist in multiple levels of caches, and these caches may be further divided by function, so that one cache holds instructions while another holds non-instruction data, which is used by the processor or processors. Memory can be further distributed and associated with different CPUs or sets of CPUs, as is known in any of various so-called non-uniform memory access (NUMA) computer architectures. The memory  304  also contains an authentication module  120  and a reference storage  125  (illustrated in  FIG.  1   ). 
     These components are illustrated as being included within the memory  304  in the computer system  300 . However, in other embodiments, some or all of these components may be on different computer systems and may be accessed remotely, e.g., via a network. The computer system  300  may use virtual addressing mechanisms that allow the programs of the computer system  300  to behave as if they only have access to a large, single storage entity instead of access to multiple, smaller storage entities. Thus, though the authentication module  120  and the reference storage  125  are illustrated as being included within the memory  304 , components of the memory  304  are not necessarily all completely contained in the same storage device at the same time. Further, although these components are illustrated as being separate entities, in other embodiments some of these components, portions of some of these components, or all of these components may be packaged together. 
     In an embodiment, the authentication module  120  and reference storage  125  include instructions that execute on the processor  302  or instructions that are interpreted by instructions that execute on the processor  302  to carry out the functions as further described in this disclosure. In another embodiment, the authentication module  120  and reference storage  125  are implemented in hardware via semiconductor devices, chips, logical gates, circuits, circuit cards, and/or other physical hardware devices in lieu of, or in addition to, a processor-based system. In another embodiment, the authentication module  120  and reference storage  125  include data in addition to instructions. 
     Although the memory bus  303  is shown in  FIG.  3    as a single bus structure providing a direct communication path among the CPUs  302 , the memory subsystem  304 , the display system  306 , the bus interface  307 , and the input/output bus interface  310 , the memory bus  303  can, in some embodiments, include multiple different buses or communication paths, which may be arranged in any of various forms, such as point-to-point links in hierarchical, star or web configurations, multiple hierarchical buses, parallel and redundant paths, or any other appropriate type of configuration. Furthermore, while the input/output bus interface  310  and the input/output bus  308  are shown as single respective units, the computer system  300  may, in some embodiments, contain multiple input/output bus interface units  310 , multiple input/output buses  308 , or both. Further, while multiple input/output interface units are shown, which separate the input/output bus  308  from various communications paths running to the various input/output devices, in other embodiments some or all of the input/output devices may be connected directly to one or more system input/output buses. 
     The computer system  300  may include a bus interface unit  307  to handle communications among the processor  302 , the memory  304 , a display system  306 , and the input/output bus interface unit  310 . The input/output bus interface unit  310  may be coupled with the input/output bus  308  for transferring data to and from the various input/output units. The input/output bus interface unit  310  communicates with multiple input/output interface units  312 ,  314 ,  316 , and  318 , which are also known as input/output processors (IOPs) or input/output adapters (IOAs), through the input/output bus  308 . The display system  306  may include a display controller. The display controller may provide visual, audio, or both types of data to a display device  305 . The display system  306  may be coupled with a display device  305 , such as a standalone display screen, computer monitor, television, or a tablet or handheld device display. In alternate embodiments, one or more of the functions provided by the display system  306  may be on board a processor  302  integrated circuit. In addition, one or more of the functions provided by the bus interface unit  307  may be on board a processor  302  integrated circuit. 
     In some embodiments, the computer system  300  is a multi-user mainframe computer system, a single-user system, or a server computer or similar device that has little or no direct user interface, but receives requests from other computer systems (clients). Further, in some embodiments, the computer system  300  is implemented as a desktop computer, portable computer, laptop or notebook computer, tablet computer, pocket computer, telephone, smart phone, network switches or routers, or any other appropriate type of electronic device. 
     It is noted that  FIG.  3    is intended to depict the representative major components of an exemplary computer system  300 . In some embodiments, however, individual components may have greater or lesser complexity than as represented in  FIG.  3   , Components other than or in addition to those shown in  FIG.  3    may be present, and the number, type, and configuration of such components may vary. 
     In some embodiments, the data storage and retrieval processes described herein could be implemented in a cloud computing environment, which is described below with respect to  FIGS.  4  and  5   . It is to be understood that although this disclosure includes a detailed description on cloud computing, implementation of the teachings recited herein are not limited to a cloud computing environment. Rather, embodiments of the present invention are capable of being implemented in conjunction with any other type of computing environment now known or later developed. 
     Cloud computing is a model of service delivery for enabling convenient, on-demand network access to a shared pool of configurable computing resources (e.g., networks, network bandwidth, servers, processing, memory, storage, applications, virtual machines, and services) that can be rapidly provisioned and released with minimal management effort or interaction with a provider of the service. This cloud model may include at least five characteristics, at least three service models, and at least four deployment models. 
     Characteristics are as follows: 
     On-demand self-service: a cloud consumer can unilaterally provision computing capabilities, such as server time and network storage, as needed automatically without requiring human interaction with the service&#39;s provider. 
     Broad network access: capabilities are available over a network and accessed through standard mechanisms that promote use by heterogeneous thin or thick client platforms (e.g., mobile phones, laptops, and PDAs). 
     Resource pooling: the provider&#39;s computing resources are pooled to serve multiple consumers using a multi-tenant model, with different physical and virtual resources dynamically assigned and reassigned according to demand. There is a sense of location independence in that the consumer generally has no control or knowledge over the exact location of the provided resources but may be able to specify location at a higher level of abstraction (e.g., country, state, or datacenter). 
     Rapid elasticity: capabilities can be rapidly and elastically provisioned, in some cases automatically, to quickly scale out and rapidly released to quickly scale in. To the consumer, the capabilities available for provisioning often appear to be unlimited and can be purchased in any quantity at any time. 
     Measured service: cloud systems automatically control and optimize resource use by leveraging a metering capability at some level of abstraction appropriate to the type of service (e.g., storage, processing, bandwidth, and active user accounts). Resource usage can be monitored, controlled, and reported, providing transparency for both the provider and consumer of the utilized service. 
     Service Models are as follows: 
     Software as a Service (SaaS): the capability provided to the consumer is to use the provider&#39;s applications running on a cloud infrastructure. The applications are accessible from various client devices through a thin client interface such as a web browser (e.g., web-based email). The consumer does not manage or control the underlying cloud infrastructure including network, servers, operating systems, storage, or even individual application capabilities, with the possible exception of limited user-specific application configuration settings. 
     Platform as a Service (PaaS): the capability provided to the consumer is to deploy onto the cloud infrastructure consumer-created or acquired applications created using programming languages and tools supported by the provider. The consumer does not manage or control the underlying cloud infrastructure including networks, servers, operating systems, or storage, but has control over the deployed applications and possibly application hosting environment configurations. 
     Infrastructure as a Service (IaaS): the capability provided to the consumer is to provision processing, storage, networks, and other fundamental computing resources where the consumer is able to deploy and run arbitrary software, which can include operating systems and applications. The consumer does not manage or control the underlying cloud infrastructure but has control over operating systems, storage, deployed applications, and possibly limited control of select networking components (e.g., host firewalls). 
     Deployment Models are as follows: 
     Private cloud: the cloud infrastructure is operated solely for an organization. It may be managed by the organization or a third party and may exist on-premises or off-premises. 
     Community cloud: the cloud infrastructure is shared by several organizations and supports a specific community that has shared concerns (e.g., mission, security requirements, policy, and compliance considerations). It may be managed by the organizations or a third party and may exist on-premises or off-premises. 
     Public cloud: the cloud infrastructure is made available to the general public or a large industry group and is owned by an organization selling cloud services. 
     Hybrid cloud: the cloud infrastructure is a composition of two or more clouds (private, community, or public) that remain unique entities but are bound together by standardized or proprietary technology that enables data and application portability (e.g., cloud bursting for load-balancing between clouds). 
     A cloud computing environment is service oriented with a focus on statelessness, low coupling, modularity, and semantic interoperability. At the heart of cloud computing is an infrastructure that includes a network of interconnected nodes. 
       FIG.  4    is a block diagram illustrating a cloud computing environment  400 , according to some embodiments of the present disclosure. As shown, cloud computing environment  400  includes one or more cloud computing nodes  410  with which local computing devices used by cloud consumers, such as, for example, personal digital assistant (PDA) or cellular telephone  420 - 1 , desktop computer  420 - 2 , laptop computer  420 - 3 , and/or automobile computer system  420 - 4  may communicate. Nodes  410  may communicate with one another. They may be grouped (not shown) physically or virtually, in one or more networks, such as Private, Community, Public, or Hybrid clouds as described hereinabove, or a combination thereof. This allows cloud computing environment  400  to offer infrastructure, platforms and/or software as services for which a cloud consumer does not need to maintain resources on a local computing device. It is understood that the types of computing devices  420 - 1 - 420 - 4  shown in  FIG.  4    are intended to be illustrative only and that computing nodes  410  and cloud computing environment  400  can communicate with any type of computerized device over any type of network and/or network addressable connection (e.g., using a web browser). 
       FIG.  5    is a block diagram illustrating a set of functional abstraction model layers  500  provided by the cloud computing environment  400 , according to some embodiments of the present disclosure. It should be understood in advance that the components, layers, and functions shown in  FIG.  5    are intended to be illustrative only and embodiments of the invention are not limited thereto. As depicted, the following layers and corresponding functions are provided: 
     Hardware and software layer  510  includes hardware and software components. Examples of hardware components include mainframes  511 ; RISC (Reduced Instruction Set Computer) architecture-based servers  512 ; servers  513 ; blade servers  514 ; storage devices  515 ; and networks and networking components  516 . In some embodiments, software components include network application server software  517  and database software  518 . 
     Virtualization layer  520  provides an abstraction layer from which the following examples of virtual entities may be provided: virtual servers  521 ; virtual storage  522 ; virtual networks  523 , including virtual private networks; virtual applications and operating systems  524 ; and virtual clients  525 . 
     In one example, management layer  530  provides the functions described below. Resource provisioning  531  provides dynamic procurement of computing resources and other resources that are utilized to perform tasks within the cloud computing environment. Metering and Pricing  532  provide cost tracking as resources are utilized within the cloud computing environment, and billing or invoicing for consumption of these resources. In one example, these resources may include application software licenses. Security provides identity verification for cloud consumers and tasks, as well as protection for data and other resources. User portal  533  provides access to the cloud computing environment for consumers and system administrators. Service level management  534  provides cloud computing resource allocation and management such that required service levels are met. Service Level Agreement (SLA) planning and fulfillment  535  provide pre-arrangement for, and procurement of, cloud computing resources for which a future requirement is anticipated in accordance with an SLA. 
     Workloads layer  540  provides examples of functionality for which the cloud computing environment can be utilized. Examples of workloads and functions that can be provided from this layer include mapping and navigation  541 ; software development and lifecycle management  542 ; virtual classroom education delivery  543 ; data analytics processing  544 ; transaction processing  545 ; and signature verification  546 . 
     The present disclosure may be a system, a method, and/or a computer program product. The computer program product may include a computer readable storage medium (or media) having computer readable program instructions thereon for causing a processor to carry out aspects of the present disclosure. 
     The computer readable storage medium is a tangible device that can retain and store instructions for use by an instruction execution device. Examples of computer readable storage media can include an electronic storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the foregoing. A non-exhaustive list of more specific examples of the computer readable storage medium includes the following: a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), a static random access memory (SRAM), a portable compact disc read-only memory (CD-ROM), a digital versatile disk (DVD), a memory stick, a floppy disk, a mechanically encoded device such as punch-cards or raised structures in a groove having instructions recorded thereon, and any suitable combination of the foregoing. A computer readable storage medium, as used herein, is not to be construed as being transitory signals per se, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through a waveguide or other transmission media (e.g., light pulses passing through a fiber-optic cable), or electrical signals transmitted through a wire. 
     Computer readable program instructions described herein can be downloaded to respective computing/processing devices from a computer readable storage medium or to an external computer or external storage device via a network, for example, the Internet, a local area network, a wide area network and/or a wireless network. The network can comprise copper transmission cables, optical transmission fibers, wireless transmission, routers, firewalls, switches, gateway computers, and/or edge servers. A network adapter card or network interface in each computing/processing device receives computer readable program instructions from the network and forwards the computer readable program instructions for storage in a computer readable storage medium within the respective computing/processing device. 
     Computer readable program instructions for carrying out operations of the present disclosure may be assembler instructions, instruction-set-architecture (ISA) instructions, machine instructions, machine dependent instructions, microcode, firmware instructions, state-setting data, or either source code or object code written in any combination of one or more programming languages, including an object oriented programming language such as Smalltalk, C++ or the like, and conventional procedural programming languages, such as the “C” programming language or similar programming languages. The computer readable program instructions may execute entirely on the user&#39;s computer, partly on the user&#39;s computer, as a stand-alone software package, partly on the user&#39;s computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer may be connected to the user&#39;s computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider). In some embodiments, electronic circuitry including, for example, programmable logic circuitry, field-programmable gate arrays (FPGA), or programmable logic arrays (PLA) may execute the computer readable program instructions by utilizing state information of the computer readable program instructions to personalize the electronic circuitry, in order to perform aspects of the present disclosure. 
     Aspects of the present disclosure are described herein with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the present disclosure. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer readable program instructions. 
     These computer readable program instructions may be provided to a processor of a general-purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks. These computer readable program instructions may also be stored in a computer readable storage medium that can direct a computer, a programmable data processing apparatus, and/or other devices to function in a particular manner, such that the computer readable storage medium having instructions stored therein comprises an article of manufacture including instructions which implement aspects of the function/act specified in the flowchart and/or block diagram block or blocks. 
     The computer readable program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other device to cause a series of operational steps to be performed on the computer, other programmable apparatus or other device to produce a computer implemented process, such that the instructions which execute on the computer, other programmable apparatus, or other device implement the functions/acts specified in the flowchart and/or block diagram block or blocks. 
     The flowchart and block diagrams in the Figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present disclosure. In this regard, each block in the flowchart or block diagrams may represent a component, segment, or portion of instructions, which comprises one or more executable instructions for implementing the specified logical function(s). In some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems that perform the specified functions or acts or carry out combinations of special purpose hardware and computer instructions. 
     The descriptions of the various embodiments of the present disclosure have been presented for purposes of illustration, but are not intended to be exhaustive or limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terminology used herein was chosen to best explain the principles of the embodiments, the practical application or technical improvement over technologies found in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein. 
     The descriptions of the various embodiments of the present invention have been presented for purposes of illustration, but are not intended to be exhaustive or limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terminology used herein was chosen to best explain the principles of the embodiments, the practical application or technical improvement over technologies found in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein.