Privacy-preserving of user profile and Real-Time Bidding(RTB) based ad delivery system through Functional Encryption(FE) and Method for the same

Abstract

The user information protection utilizing function cryptography and the real-time bidding-based digital advertising delivery system utilizing the same according to the present invention may include: a supplier-side platform server that performs an advertising request for the sale of advertising inventory exposed to a user terminal; a demand-side platform server that bids on advertising campaigns to be placed on the advertising inventory; an advertising exchange server that mediates a real-time auction of the advertising inventory between the supplier-side platform server and the demand-side platform server; and a third trusted authority server that transmits an encryption key to encrypt the user profile of the user terminal to the user terminal, generates a function key by encrypting a part of the bidding function transmitted from the demand-side platform, and transmits the generated function key to the demand-side platform.

Description

Technology Field

[0001] The present invention relates to a real-time bidding-based advertising delivery system (RTB), and more specifically, to user information protection utilizing a functional cryptography that can protect user profiles and internal advertiser bidding algorithms, thereby enhancing security, and a real-time bidding-based digital advertising delivery system utilizing the same. Background Technology

[0003] Advertising is a paid information delivery activity conducted by advertisers through various media with the goal of influencing customers' attitudes or behaviors and ultimately leading them to purchase the advertiser's products. Such advertising aims to induce actions that are valuable to the advertiser's business, such as purchasing; conversion refers to the process where a customer who has interacted with an advertisement (e.g., clicking on a text / image ad, viewing a video ad) performs the action targeted by the advertisement.

[0004] The emergence of various online advertising media, such as search ads, banner ads, reward ads, and social media ads, has made it possible to provide diverse forms of advertising using various media. Depending on the type of online advertising medium, characteristics such as advertising execution costs, conversion rates, the scale of exposure, and the characteristics of the customers exposed to the ads can vary.

[0005] The online advertising market and related research have developed rapidly in a short period of time and are constantly growing to acquire more superior customers more conveniently and at lower costs.

[0006] In the past, advertisers (or agencies) had to directly contact media outlets to negotiate rates, finalize contracts, and purchase ad inventory to display their ads on specific media. This traditional method required significant time and resources, and because ad inventory was purchased in bulk—such as by media or space unit—ads were sometimes displayed to users who did not match the advertiser's target audience, resulting in low performance.

[0007] Recently, programmatic buying, which involves purchasing advertising inventory through automated software systems, has become popularized. Systems have come to efficiently execute tasks previously performed by humans. Programmatic advertising automatically analyzes users, displays ads tailored to their gender, age, and interests, and optimizes campaigns by analyzing advertising data. However, such programmatic advertising has raised concerns regarding personal information protection, as it exposes even sensitive user information.

[0008] The online advertising industry is facing demands for change due to the surging interest in user privacy protection. Currently, online and digital advertising is delivered in a customized manner based on user and webpage information through Real-Time Bidding (RTB) techniques. When a user accesses a webpage containing an ad space, personal details such as age, race, gender, language, and country, as well as the user's current location, type of device used, and category of visited websites, are transmitted to the RTB network. Furthermore, based on the user's web browsing history accumulated through cookies and shopping cart data from online stores, interests and preferences are inferred; subsequently, advertisers bid on the advertisements to display to the user based on this data.

[0009] Although the amount of user personal information exposed through RTB has decreased to some extent due to the abolition of third-party cookies and the emergence of legal regulations such as Europe's GDPR and the US CCPA, user data transmitted in advertising requests still contains data that infringes on privacy and is being stored and utilized by businesses seeking to improve targeting performance and profitability, so there is a need to protect user personal information.

[0010] Meanwhile, the information described above is presented merely as background information to aid in understanding the present invention. No decision has been made, nor is any claim made, regarding whether any of the above contents are applicable as prior art relating to the present invention. Prior art literature

[0012] Republic of Korea Published Patent Application No. 10-2022-0169768 (Date of publication: Dec. 28, 2022) The problem to be solved

[0013] The present invention was devised to solve the aforementioned problems, and one technical objective of the present invention is to provide user information protection utilizing functional cryptography capable of protecting personal information in real-time bidding advertising (RTB) while simultaneously protecting trade secrets, such as internal algorithms that determine an advertiser's bid price, and a real-time bidding-based digital advertising delivery system utilizing the same. means of solving the problem

[0015] A user information protection system utilizing a function cryptography and a real-time bidding-based digital advertising delivery system utilizing the same, according to an embodiment of the present invention for realizing the above-mentioned technical problem, may include: a supplier-side platform server that performs an advertising request for the sale of advertising inventory exposed to a user terminal; a demand-side platform server that bids on advertising campaigns to be posted on the advertising inventory; an advertising exchange server that mediates a real-time auction of the advertising inventory between the supplier-side platform server and the demand-side platform server; and a third trusted authority server that transmits an encryption key to encrypt the user profile of the user terminal to the user terminal, generates a function key by encrypting a part of the bidding function transmitted from the demand-side platform, and transmits the generated function key to the demand-side platform.

[0016] Here, the third trusted authority server can generate a master key pair consisting of a master public key (MPK) and a master private key (MSK), transmit the MPK to the user terminal to encrypt the user profile, and generate a function key by encrypting a part of the bidding function with the MSK and transmit it to the demand-side platform server.

[0017] In addition, the third trusted authority server may transmit a hash value used to recognize the MPK when the MPK is generated to the user terminal along with the MPK.

[0018] In addition, the user terminal can transmit an encrypted user profile encrypted by the MPK and a hash value corresponding to the MPK to the provider-side platform server.

[0019] Additionally, the bidding function includes a similarity derivation function that determines the similarity between a user and an advertising campaign and a bid price determination function that determines the bid price for purchasing the advertising inventory, and the similarity derivation function can be transmitted to the third trusted institution server.

[0020] In addition, the demand-side platform server can decrypt the encrypted user profile with the function key to obtain the output value of the similarity derivation function for the user profile, and then determine the bid price for the advertising inventory through the bid price determination function.

[0021] In addition, the user-side platform server can match a function key corresponding to the MPK used when creating the encrypted user profile through the hash value transmitted along with the encrypted user profile.

[0022] Additionally, it may further include an advertising media server that provides the advertising inventory within the website to which the user terminal is connected and transmits an encrypted user profile encrypted with the encryption key to the provider-side platform server.

[0023] In addition, the advertising media server may post the advertising campaign won by the advertising exchange server to the advertising inventory and receive a commission from the advertiser of the winning advertising campaign.

[0024] A digital advertising delivery method using a digital advertising delivery system based on real-time bidding utilizing user information protection using a function cryptography according to an embodiment of the present invention comprises: an advertising request step (S110) in which a user terminal is connected to a website containing advertising inventory and makes an advertising request to the supplier-side platform server; an encryption key request and encryption data generation step (S120) in which, in response to the advertising request, the third trusted institution server transmits an encryption key and a corresponding hash value to the user terminal to generate an encrypted user profile; and a similarity derivation function request step (S130) in which, in response to the advertising request, the third trusted institution server requests the transmission of a similarity derivation function for calculating user similarity to the demand-side platform server. In response to the above advertisement request, the third trusted institution server transmits an encryption key and a hash value to the user terminal, generates a function key by encrypting the similarity derivation function with a secret key corresponding to the encryption key, and transmits it to the demand-side platform server, thereby generating and transmitting a function key pair (S140); the demand-side platform server decrypts the encrypted user profile with a function key corresponding to the hash value of the encryption key used to generate the encrypted user profile, derives the output value of the similarity derivation function, and determines the bid price of the advertisement inventory, thereby including an encrypted data decryption step (S150).

[0025] Herein, the method may further include a real-time advertising bidding step (S160) in which the demand-side platform server transmits the determined bid price to the advertising exchange server to proceed with bidding for the advertising inventory; and an advertising campaign winning and providing step (S170) in which the advertising exchange server determines the winning bid for an advertising campaign based on a plurality of bid prices and provides the winning advertising campaign to the user terminal through the supplier-side platform server.

[0026] In addition, the third trusted authority server may generate a functional cryptographic key pair comprising a plurality of master public keys and a plurality of corresponding master private keys used to encrypt the user profile, and transmit a plurality of hash values ​​corresponding to the master public keys and the plurality of master public keys to the user terminal.

[0027] In addition, the user terminal can encrypt the user profile using one of the multiple master public keys transmitted from the third trusted authority server, and transmit the hash value corresponding to the encrypted user profile and the encryption key used to the provider-side platform server.

[0028] In addition, the user-side platform server receives multiple function keys encrypted with the similarity derivation function from the third trusted institution server, and can decrypt the encrypted user profile by determining a function key corresponding to the encrypted user profile among the multiple function keys based on a hash value transmitted from the supplier-side platform server.

[0029] The technical problems to be solved by the present invention are not limited to those mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art to which the present invention belongs from the description below. Effects of the invention

[0031] According to an embodiment of the present invention, through a real-time bidding digital ad delivery system based on functional encryption, it is possible to protect the personal information of users consuming ads while simultaneously protecting trade secrets, such as internal algorithms that determine the bid price of advertisers. Brief explanation of the drawing

[0033] FIG. 1 is a schematic diagram of a user information protection system utilizing a function password according to the present embodiment and a real-time bidding-based digital advertising delivery system utilizing the same. FIG. 2 is a schematic diagram of a method for protecting user information using a function password according to the present embodiment and delivering real-time bidding-based digital advertisements using the same. FIG. 3 is a schematic diagram showing an example of a user profile of the present embodiment. FIG. 4 is a schematic diagram showing an example of a user structure of a user profile of the present embodiment. FIG. 5 is a schematic diagram showing the similarity derivation functions of the present embodiment. Figure 6 is a schematic diagram showing the flow of a real-time auction of an advertisement using an encrypted user profile and a function encryption key. Specific details for implementing the invention

[0034] The terms used in this specification will be briefly explained, and the present invention will be described in detail. The terms used in this invention have been selected to be as generally used as possible, taking into account their functions within the invention; however, these terms may vary depending on the intent of those skilled in the art, case law, the emergence of new technologies, etc. Additionally, in specific cases, terms have been arbitrarily selected by the applicant, and in such cases, their meanings will be described in detail in the relevant description of the invention. Therefore, the terms used in this invention should be defined not merely by their names, but based on their meanings and the overall content of the invention.

[0035] The system, device, and each module or unit constituting the same according to the embodiments may have aspects that are entirely hardware or partially hardware and partially software. For example, each component of the system refers to a combination of hardware and software driven by said hardware. The hardware may be a data processing device including a CPU (Central Processing Unit) or other processor. Additionally, the software driven by the hardware may refer to a running process, object, executable, thread of execution, program, etc.

[0036] When a part of a specification is described as "including" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components.

[0037] Embodiments of the present invention are described below with reference to the attached drawings so that those skilled in the art can easily implement them. However, the present invention may be embodied in various different forms and is not limited to the embodiments described herein.

[0038] Various embodiments of the present invention will be described in more detail below with reference to the attached drawings. However, in describing the present invention, if it is determined that a detailed description of related known functions or configurations may unnecessarily obscure the essence of the present invention, such detailed description will be omitted.

[0040] FIG. 1 schematically illustrates a system for protecting user information using a function cryptography according to the present embodiment and a real-time bidding-based digital advertising delivery system using the same; FIG. 2 schematically illustrates a method for protecting user information using a function cryptography according to the present embodiment and a real-time bidding-based digital advertising delivery method using the same; FIG. 3 schematically illustrates an example of a user profile of the present embodiment; FIG. 4 schematically illustrates an example of a user structure of a user profile of the present embodiment; FIG. 5 schematically illustrates similarity derivation functions of the present embodiment; and FIG. 6 schematically illustrates the flow of a real-time auction of an advertisement using an encrypted user profile and a function cryptography key.

[0042] As illustrated in FIG. 1, a user information protection system utilizing a function cryptography according to an embodiment of the present invention and a real-time bidding-based digital advertising delivery system (100, hereinafter referred to as the advertising delivery system) utilizing the same may include an advertising media server (110) (Publisher), a supplier-side platform server (120) (SSP; Supply Side Platform), an advertising exchange server (130) (ADX; Ad Exchange), a demand-side platform server (140) (DSP; Demand Side Platform), and a third trusted institution server (150) (TTP; Trusted Third Party). In this embodiment, the supplier-side platform server (120), the demand-side platform server (140), and the advertising exchange server (130) may form a Real-Time Bidding (RTB) network.

[0043] An advertising media server (110) may have an advertising inventory that displays advertising campaigns exposed to a user terminal (10). The advertising media server (110) may include, for example, a website, an application, a video, etc., as a means of communication used by an advertiser to deliver advertising campaigns to consumers. This advertising media server (110) includes an advertising inventory, which is an advertising space or advertising surface where advertisements are displayed, and the advertising inventory may be designated, for example, as a specific area where advertisements are displayed within a specific page of a website, or a specific area where advertisements are displayed within an application. When a user terminal (10) connects to the website or application provided by the advertising media server (110), the server receives and stores an encrypted user profile from the user terminal (10), and can display customized advertisements corresponding to the user profile in the advertising inventory by utilizing the stored encrypted user profile. The advertising media server (110) can post the advertisement or advertising campaign of the advertiser who was finally awarded the bid through a real-time bidding process onto the advertising inventory and provide it to the user terminal (10), and receive an advertising revenue commission from the awarded advertiser. Here, an advertising campaign refers to a series of advertising activities carried out systematically and organizationally based on a specific topic within a set period with a specific purpose. That is, an advertising campaign is not a one-time advertisement intended to obtain immediate results, but a long-term advertisement conducted with a specific goal. Meanwhile, an encrypted user profile stored in the advertising media server (110) and used to display customized advertisements (or advertising campaigns) can be transmitted to the provider-side platform server (120) and used by the advertising exchange server (130) for real-time bidding and similarity determination of various advertisers.The user profile provided from the user terminal contains sensitive information such as personal details like the user's age, race, gender, language, and country, the user's current location, the type of device used, classification of websites accessed, web browsing history, shopping cart information, and keywords used, thus requiring information security for the existing RTB system. To this end, in this embodiment, the user profile containing sensitive information is encrypted using an encryption key provided by a third trusted authority server (150) and then transmitted to the advertising media server (110) and the supplier-side platform server (120).

[0044] The supplier-side platform server (120) is a supplier-side platform server that conducts an ad auction using the Real Time Bidding (RTB) method together with the ad exchange server (130) and the demand-side platform server (140). The supplier-side platform server (120) can receive a request to sell ad inventory from the ad media server (110) based on an encrypted user profile transmitted from the ad media server (110). The request to sell ad inventory includes the action of requesting an ad campaign to be displayed on the ad inventory. In response to the request to sell ad inventory, the supplier-side platform server (120) can request the ad exchange server (130) to bid on ad campaigns to purchase the ad inventory. The supplier-side platform server (120) can transmit the ad campaign that was won at the ad exchange server (130) to the ad media server (110) and transmit the ad cost from the advertiser of the selected ad campaign to the ad media server (110).

[0045] The demand-side platform server (140) can receive multiple advertising campaigns intended for sale from multiple advertisers through the advertiser terminal (20), and is a demand-side platform server capable of bidding the received advertising campaigns to the advertising exchange server (130) in response to a bidding request from the supplier-side platform server (120). Bidding on advertising campaigns may include the action of providing advertising campaigns that wish to purchase advertising inventory to the advertising exchange server (130) along with the bidding price. When the demand-side platform server (140) receives user profiles, user terminal information, and web page information accessed by the user from the advertising exchange server (130), it can predict the user's reaction when the advertising inventory intended for bidding is exposed to the user. For example, it can predict whether the user will click on an advertisement for an insurance product suitable for the user's gender and age group when the advertisement is exposed. Alternatively, it can predict whether the user will be led to a purchase by exposing a shopping cart that the user passed by without payment at an online shopping mall. Subsequently, the cost required to expose the advertisement is estimated, and the final bidding price is determined. To this end, the bidding function of the demand-side platform server (140) may be configured to include a similarity derivation function that determines the similarity between the user and the ad campaign, and a bid price determination function that determines the bid price for purchasing ad inventory.

[0046] The ad exchange server (130) is an ad exchange that receives an ad bidding request from the supplier-side platform server (120) and a bid participation request from the demand-side platform server (140), conducts a real-time auction, and transmits the final winning bidder (winning ad campaign) to the supplier-side platform server. The ad exchange server (130) can select the ad campaign capable of generating the highest ad revenue as the winning bidder for the ad inventory by considering the bid prices of the ad campaigns bid on by the demand-side platform server (140). The advertiser of the selected ad campaign pays the advertising costs associated with placing the ad campaign on the ad media server (110) that sold the ad inventory.

[0047] The third trusted authority server (150) is a third trusted authority for encrypting the user profile transmitted through the advertising media server (110) and the similarity derivation function of the advertiser transmitted from the demand-side platform server (140). The user profile, collected from the advertising media server (110) and used in real-time advertising auctions through the supplier-side platform server (120), contains various personal information of the user, and the bidding function for purchasing the advertiser's advertising inventory from the demand-side platform server (140) is a trade secret of the advertiser, thus requiring information protection. That is, for the information security of both the user consuming the advertisement and the advertiser providing the advertisement, encryption through a third authority trusted by the real-time auction participants is required, and to this end, this embodiment may further include a third trusted authority server (150). The third trusted authority may be a platform operator such as Google or Meta, or a business operator performing the role of a Certificate Authority in the Web Public Key Infrastructure (Web PKI). The third trusted institution server (150) of this embodiment can provide a real-time auction with established information security by encrypting the user profile and the advertiser's bidding function using a function encryption method.

[0048] The third trusted authority server (150) of the present embodiment can generate, manage, and transmit keys used in the Inner-Product Functional Encryption (IPFE) method. The main functions of the third trusted authority server (150) may include generating a master key pair, such as a Master Secret Key (MSK) and a Master Public Key (MPK, encryption key), managing the validity period of each key pair, performing hash value calculations as identifiers for each key pair, and generating an overlapping key pair, which is a new key pair generated before the validity period of the key pair expires. The main operations of the third trusted institution server (150) may include receiving a request from the browser of the user terminal (10) and transmitting a valid MPK and the hash value of the corresponding key to the user terminal (10), and generating a function key by encrypting the similarity derivation function of the bidding function transmitted from the demand-side platform server (140) with an MSK corresponding to the valid MPK and transmitting it to the demand-side platform server (140).

[0049] As illustrated in FIG. 2, the digital advertising delivery method using a user information protection system utilizing a function encryption of the present embodiment having the above-described configuration and a real-time bidding-based digital advertising delivery system utilizing the same may include an advertising request step (S110), an encryption key request and encryption data generation step (S120), a similarity derivation function request step (S130), a function encryption key pair generation and delivery step (S140), an encryption data decryption step (S150), a real-time advertising bidding step (S160), and an advertising campaign winning and provision step (S170).

[0050] According to the present embodiment, when a user accesses a website with an advertising area provided by an advertising media server (110) using a browser (or app) of a user terminal (10), real-time advertising bidding (sale of advertising inventory) is performed through the RTB of the present embodiment, and the final winning advertisement (advertising campaign) can be exposed to the user through the user terminal (10).

[0051] In the ad request step (S110), when the user terminal (10) accesses a website provided by the ad media server (110), the ad media server (110) can make an ad request to the RTB network. Here, the ad media server (110) can receive a user profile from the user terminal (10) and transmit it to the RTB network for bidding on and displaying user-customized ads.

[0052] As illustrated in FIG. 3, the user profile of the present embodiment is data containing various user information and can be composed of a binary vector of size 2,000 expressed in binary encoding. User information that can be used for advertising is generally represented by hundreds to thousands of pieces of information. Of the approximately 6,000 codes defined by Google, about 600 can be used as user information categories, and the IAB defines about 1,500 Audience Taxons for use in user classification. Therefore, user information can be sufficiently represented with a vector size of 2,000. Referring to FIG. 3, for example, a user profile of "a 33-year-old single male who likes soccer and comedy movies and is planning to buy a new vehicle" can be constructed by assigning the value of each corresponding index to 1 and filling the other indices with 0, with the indices corresponding to each information being 30-34 (6), Male (50), Single (162), Comedy Movie (470), Soccer (663), and New Vehicles (806).

[0053] Meanwhile, the user structure transmitted from the advertising media server (110) of the present embodiment to the provider-side platform server (120) of the RTB network stores a user profile encrypted with the MPK of the third trusted authority server (150), and may have differences from the user structure previously provided to the RTB network.

[0054] As illustrated in FIG. 4, the field configuration of the user structure of OpenRTB, an example of an existing RTB network, and the user structure of the present embodiment may differ. OpenRTB refers to an interface for Real-Time-Bidding (RTB) between an ad seller and a buyer. As the need for a standard interface for exchanging ads arose, DSP companies such as DataXu, Fiksu, and [X+1], and SSP companies such as Nexage, Pubmatic, Smaata, and Jumptap, released OpenRTB 1.0 in February 2011 to standardize communication between parties during ad transactions, and it was adopted as a standard by the IAB in January 2012. Referring to FIG. 3, the user structure of OpenRTB provided by the existing RTB network stores the user's personal information through user details, interests, and various custom values. In contrast, the user structure of the present embodiment can store and provide user information through three representative fields consisting of ttp, keyhash, and profile. The ttp and keyhash fields of the user structure in this embodiment can function as identifiers to identify which third trusted authority server (150)'s MPK the user profile has been encrypted with. There may be multiple third trusted authorities (TTPs), and each third trusted authority has a different valid key pool. As a result, when decrypting the encrypted user profile at the provider-side platform server (120) of the RTB network, it is necessary to identify which TTP's function key should be used, and the TTP and MPK can be identified through the ttp and keyhash fields of the user structure.

[0055] The encryption key request and encryption data generation step (S120) involves requesting an encryption key from the browser of the user terminal (10) to the third trusted authority server (150) and encrypting the user profile with the received encryption key to generate an encrypted user profile. The encrypted user profile is provided to the advertising exchange server (130) via the advertising media server (110) and the supplier-side platform server (120) and can be utilized for the advertiser's bid judgment and advertising amount determination. The encrypted user profile is generated on the user terminal (10) or the browser (or app) of the user terminal (10) and transmitted to the advertising media server (110), and the advertising media server (110) can generate an RTB user structure and transmit it to the RTB network. In response to the encryption key request from the user terminal (10), the third trusted authority server (150) generates a functional encryption key pair (MPK, MSK) and the MPK (Master Public Key) and the corresponding to the MPK. It can be transmitted to the user terminal (10). The user terminal (10) is a user profile for online advertising ( ) generates a user profile ( MPK transmitted from the third trusted authority server (150) Encrypting ) to encrypt the encrypted user profile( ) can be generated. The encrypted user profile generated in this way ( As the ) is transmitted from the advertising media server (110) to the supplier-side platform server (120), then to the advertising exchange server (130) and the demand-side platform server (140), a real-time auction can be conducted. Encrypted user profile ( ) can be transmitted using the user structure illustrated in FIG. 4 and described above.

[0056] In the similarity derivation function request step (S130), when an advertisement request from the supplier-side platform server (120) is received in the RTB network, the third trusted agency server (150) may request the similarity derivation function of the bidding function from the advertiser terminal (20) through the demand-side platform server (140). The third trusted agency server (150) may generate a function key by encrypting the similarity derivation function received from the demand-side platform server (140) with an MSK corresponding to the valid MPK provided to the user terminal (10).

[0057] As illustrated in FIG. 5, the demand-side platform server (140) may include a similarity derivation function that calculates a User Score using a user profile provided through an RTB network in response to an ad bidding request. The User Score serves as a measure for determining the similarity between the user and the target population (age group, gender, region, income level, etc.) set by the advertiser. For a user profile represented as a binary vector, the demand-side platform server (140) uses two vector dot product functions, and the vector dot product function and This can represent the target user base set in two different advertising campaigns. Each value of the vector dot product function, based on the index of the binary vector such as age group, gender, and interests, represents the weight or priority of the advertising campaign for that index. For example, in the case of a user, it can be seen that the user score of advertising campaign b is higher. Since the specific algorithm for determining the bid price falls within the realm of trade secrets of the demand-side platform server (140), transmitting the function for determining the bid price to the third-party trusted institution server (150) can be burdensome for the demand-side platform server (140). Therefore, the existing bidding algorithm (bidding function) can be divided into two parts, and only the similarity derivation function that derives the “user suitability score” from the user profile can be transmitted to the third-party trusted institution server (150), and the function encryption key can be received.

[0058] The function cryptographic key pair generation and transmission step (S140) is to conduct a real-time auction on the RTB network in response to an ad request from the supplier-side platform server (120) and an ad campaign bid request from the demand-side platform server (140), and the third trusted institution server (150) provides a user profile ( A valid MPK for encrypting ) and the hash value of the corresponding key are transmitted, and a similarity derivation function received from the user-side platform server (140) ( Encrypting ) with the MSK corresponding to the valid MPK to form the function encryption key( ) can be generated and transmitted to the user-side platform server (140). At this time, the third trusted institution server (150) receives a request from the user-side platform server (140) for the generation of a function encryption key, in addition to a similarity derivation function ( When ) is received, verification of this function can be performed. Verification of whether the function received from the user-side platform server (140) is a malicious function intended to restore the original user profile, etc., may be performed. In addition, the third trusted authority server (150) recognizes the encryption key for encrypting the user profile by using a hash value (MPK) corresponding to the encryption key ( ) to the user-side platform server (140) function encryption key ( It can be transmitted together with ). That is, since the third trusted authority server (150) can be composed of one or more and the third trusted authority server (150) can operate multiple encryption key pairs, a matching hash value ( ) is transmitted along with the encryption key pair.

[0059] As described above, an encrypted user profile by the third trusted institution server (150) ( ), hash value( ) and function cryptographic key( Once the creation and delivery of ) is complete, a real-time auction of advertisements utilizing an encrypted user profile and a function encryption key can be conducted, as illustrated in FIG. 6.

[0060] As illustrated in FIG. 6, the encrypted data decryption step (S150) is an encrypted user profile (transmitted from the provider-side platform server (120) along with an advertisement request) ) can be decrypted with a corresponding function encryption key to derive an intermediate parameter of the user suitability score and determine the bid price for the advertising campaign based thereon. Here, the demand-side platform server (140) encrypts the user profile ( Before decrypting ), the corresponding encrypted user profile ( A function encryption key matching ) can be searched. At this time, an encryption user profile ( Hash value transmitted along with ) A matching function cryptographic key can be retrieved using ). Encryption user profile( Matching of function cryptographic keys corresponding to ), encryption user profile( When the bid price determination is completed based on the decryption of ) and the user suitability score, the determined bid price can be transmitted to the ad exchange server (130).

[0061] In the real-time ad bidding stage (S160), bids from various demand-side platform servers (140) corresponding to the ad bidding for the ad inventory of the ad media server (110) are received, and the ad bidding can proceed. The ad exchange server (130) can consider the bid prices of the bidders for the ad campaigns and select an ad campaign capable of generating high ad revenue as the winner of the ad inventory.

[0062] The advertising campaign winning and provision step (S170) may select and win one of the advertising campaigns that have bid on the advertising inventory. The advertiser of the winning advertising campaign pays the advertising cost for placing the advertising campaign on the advertising media server (110) that sold the advertising inventory, and the advertising media server (110) may display the winning advertising campaign on the advertising inventory to expose it to users. The advertising cost provided to the advertising media server (110) may be determined according to the bidding price and bidding method determined in correspondence with the advertising campaign. For example, if the bidding price and bidding method for the first advertising campaign are determined as a CPM of 100 won, the advertising cost may be set at 100 won per 1,000 impressions, and if the bidding price and bidding method for the second advertising campaign are determined as a CPC of 200 won, the advertising cost may be set at 200 won per click, but the determination of the advertising cost is not limited to this and may be made through various contractual matters.

[0064] Meanwhile, the functional operations and embodiments of the subject described herein may be implemented as digital electronic circuits, or as computer software, firmware, or hardware comprising the structures and structural equivalents disclosed herein, or as a combination of one or more of these. The embodiments of the subject described herein may be implemented as one or more computer program products, that is, as one or more modules relating to computer program instructions encoded on a tangible program storage medium for controlling the operation of a control system or for execution by such control system.

[0065] A computer-readable medium may be a machine-readable storage device, a machine-readable storage substrate, a memory device, a composition of a material that affects a machine-readable radio wave signal, or a combination of one or more of these.

[0066] In this specification, the terms “system” or “device” encompass all mechanisms, devices, and machines for controlling data, including, for example, programmable processors, computers, or multiple processors or computers. In addition to hardware, the control system may include code that forms an execution environment for a computer program upon request, such as, for example, code constituting processor firmware, a protocol stack, a database management system, an operating system, or a combination of one or more of these.

[0067] A computer program (also known as a program, software, software application, script, or code) may be written in any form of a programming language, including compiled or interpreted languages, or a priori or procedural languages, and may be deployed in any form, including a standalone program, a module, a component, a subroutine, or other unit suitable for use in a computer environment. A computer program does not necessarily correspond to a file in a file system. A program may be stored in a single file provided to the requested program, in multiple interacting files (e.g., a file storing one or more modules, subprograms, or parts of code), or in a part of a file containing other programs or data (e.g., one or more scripts stored within a markup language document). A computer program may be deployed to be executed on multiple computers or a single computer located at a single site or distributed across multiple sites and interconnected by a communication network.

[0068] Meanwhile, computer-readable media suitable for storing computer program instructions and data may include all forms of non-volatile memory, media, and memory devices, such as semiconductor memory devices like EPROM, EEPROM, and flash memory devices, magnetic disks like internal hard disks or external disks, magneto-optical disks, and CD-ROM and DVD-ROM disks. Processors and memory may be supplemented by or integrated with special-purpose logic circuits.

[0069] An embodiment of the subject described herein may be implemented in a computing system comprising, for example, a backend component such as a data server, for example, a middleware component such as an application server, for example, a frontend component such as a client computer having a web browser or a graphical user interface through which a user can interact with the embodiment of the subject described herein, or any combination of one or more such backend, middleware, or frontend components. Components of the system may be interconnected by any form or medium of digital data communication, such as a communication network.

[0070] Although this specification contains details of a number of specific embodiments, they should not be understood as limiting the scope of any invention or claimables, but rather as descriptions of features that may be specific to a particular embodiment of a particular invention. Likewise, specific features described in this specification in the context of individual embodiments may be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may also be implemented in multiple embodiments individually or in any appropriate sub-combination. Furthermore, while features may operate in a specific combination and be described as initially claimed, one or more features from the claimed combination may be excluded from the combination in some cases, and the claimed combination may be changed to a sub-combination or a variation of the sub-combination.

[0071] Furthermore, although operations are described in the drawings in a specific order in this specification, it should not be understood that such operations must be performed in that specific or sequential order depicted to obtain a desirable result, or that all depicted operations must be performed. In certain cases, multitasking and parallel processing may be advantageous. Additionally, the separation of the various system components of the embodiments described above should not be understood as requiring such separation in all embodiments, and it should be understood that the described program components and systems can generally be integrated together into a single software product or packaged into multiple software products.

[0072] As such, this specification is not intended to limit the invention to the specific terms presented. Accordingly, although the invention has been described in detail with reference to the examples described above, those skilled in the art may make modifications, changes, and variations to these examples without departing from the scope of the invention. The scope of the invention is defined by the claims set forth below rather than by the detailed description above, and all modifications or variations derived from the meaning and scope of the claims and their equivalents should be interpreted as being included within the scope of the invention. Explanation of the symbols

[0074] 10 : User terminal 20 : Advertiser's terminal 100: Digital Advertising Delivery System 110 : Advertising Media Server 120 : Supplier-side platform server 130 : Ad Exchange Server 140 : Demand-side platform server 150 : Third-party trusted authority server

Claims

Claim 1 A digital advertising delivery system based on user information protection using function encryption and real-time bidding using the same, comprising: a supplier-side platform server that performs an advertising request for the sale of advertising inventory exposed to a user terminal; a demand-side platform server that bids on advertising campaigns to be placed on the advertising inventory; an advertising exchange server that mediates a real-time auction of the advertising inventory between the supplier-side platform server and the demand-side platform server; and a third trusted authority server that transmits an encryption key to encrypt the user profile of the user terminal to the user terminal, generates a function key by encrypting a part of the bidding function transmitted from the demand-side platform, and transmits it to the demand-side platform. Claim 2 A user information protection system utilizing function encryption and a real-time bidding-based digital advertising delivery system utilizing the same, wherein, in claim 1, the third trusted authority server generates a master key pair composed of a master public key (MPK) and a master private key (MSK), transmits the MPK to the user terminal to encrypt the user profile, and encrypts a part of the bidding function with the MSK to generate a function key and transmits it to the demand-side platform server. Claim 3 A user information protection system utilizing a function cryptography and a real-time bidding-based digital advertising delivery system utilizing the same, wherein, in claim 2, the third trusted authority server transmits a hash value used to recognize the MPK together with the MPK to the user terminal when the MPK is generated. Claim 4 A user information protection system utilizing a function cryptography and a real-time bidding-based digital advertising delivery system utilizing the same, wherein, in claim 3, the user terminal transmits an encrypted user profile encrypted by the MPK and a hash value corresponding to the MPK to the provider-side platform server. Claim 5 A user information protection system utilizing a function encryption and a real-time bidding-based digital advertising delivery system utilizing the same, wherein, in claim 4, the bidding function includes a similarity derivation function for determining similarity between a user and an advertising campaign and a bid price determination function for determining a bid price for purchasing advertising inventory, and the similarity derivation function is transmitted to the third trusted authority server. Claim 6 A user information protection system utilizing a function encryption and a real-time bidding-based digital advertising delivery system utilizing the same, wherein, in claim 5, the user-side platform server decrypts the encrypted user profile with the function key to obtain the output value of the similarity derivation function for the user profile, and then determines the bid price for the advertising inventory through the bid price determination function. Claim 7 A user information protection system utilizing a function cryptography and a real-time bidding-based digital advertising delivery system utilizing the same, wherein, in claim 6, the user-side platform server matches a function key corresponding to the MPK used when creating the encrypted user profile through a hash value transmitted together with the encrypted user profile. Claim 8 A user information protection system utilizing function encryption and a real-time bidding-based digital advertising delivery system utilizing the same, characterized in that, in claim 1, it further comprises an advertising media server that provides the advertising inventory within a website to which the user terminal is connected and transmits an encrypted user profile encrypted with the encryption key to the provider-side platform server. Claim 9 A user information protection system utilizing function encryption and a real-time bidding-based digital advertising delivery system utilizing the same, wherein, in claim 8, the advertising media server posts an advertising campaign awarded by the advertising exchange server to the advertising inventory and receives a commission from the advertiser of the awarded advertising campaign. Claim 10 In an RTB network comprising a supplier-side platform server, a demand-side platform server, an ad exchange server mediating real-time auctions of ad inventory, and a third trusted authority server for encrypting supplier-side and demand-side information, the method comprises: an ad request step (S110) in which a user terminal is connected to a website containing ad inventory and makes an ad request to the supplier-side platform server; an encryption key request and encryption data generation step (S120) in which, in response to the ad request, the third trusted authority server transmits an encryption key and a corresponding hash value to the user terminal to generate an encrypted user profile; a similarity derivation function request step (S130) in which, in response to the ad request, the third trusted authority server requests the demand-side platform server to transmit a similarity derivation function for calculating user similarity; a function encryption key pair generation and transmission step (S140) in which, in response to the ad request, the third trusted authority server transmits the encryption key and hash value to the user terminal, generates a function key by encrypting the similarity derivation function with a secret key corresponding to the encryption key, and transmits it to the demand-side platform server; the demand-side platform A digital advertising delivery method using a digital advertising delivery system based on real-time bidding utilizing a function encryption, comprising: an encryption data decryption step (S150) in which the server decrypts the encrypted user profile using a function key corresponding to the hash value of the encryption key used to generate the encrypted user profile, derives the output value of the similarity derivation function, and determines the bid price of the advertising inventory. Claim 11 A digital advertisement delivery method using a digital advertisement delivery system based on real-time bidding utilizing a function encryption, further comprising: a real-time advertisement bidding step (S160) in which the demand-side platform server transmits the determined bid price to the advertisement exchange server to proceed with bidding for the advertisement inventory; and an advertisement campaign awarding and provision step (S170) in which the advertisement exchange server determines the award of an advertisement campaign based on a plurality of bid prices and provides the awarded advertisement campaign to the user terminal through the supplier-side platform server. Claim 12 A digital advertisement delivery method using a user information protection utilizing function cryptography and a real-time bidding-based digital advertisement delivery system utilizing the same, wherein, in claim 10, the third trusted authority server generates a function cryptographic key pair comprising a plurality of master public keys used to encrypt the user profile and a plurality of corresponding master private keys, and transmits a plurality of hash values ​​corresponding to the master public keys and the plurality of master public keys to the user terminal. Claim 13 A digital advertisement delivery method using a user information protection utilizing function cryptography and a real-time bidding-based digital advertisement delivery system utilizing the same, wherein, in claim 12, the user terminal encrypts a user profile using one of a plurality of master public keys transmitted from the third trusted authority server and transmits a hash value corresponding to the encrypted user profile and the encryption key used to the supplier-side platform server. Claim 14 A digital advertising delivery method using a user information protection utilizing function encryption and a real-time bidding-based digital advertising delivery system utilizing the same, wherein, in claim 13, the user-side platform server receives a plurality of function keys encrypted with the similarity derivation function from the third trusted authority server, determines a function key corresponding to the encrypted user profile among the plurality of function keys based on a hash value transmitted from the supplier-side platform server, and decrypts the encrypted user profile.

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