Distributed ledgers, such as blockchains, are transparent and ensure integrity by design. Any party who has access to the distributed ledger can read the data it contains. Distributed ledgers are particularly useful in scenarios where multiple institutions want to keep consensus and provide public verifiability of some statement. One such scenario is “mass balancing.” In mass balancing, a producer of some product or service is entitled to produce a quota (e.g., by a governmental or a non-governmental organization). This quota represents a maximum value that is publicly known (e.g., one million barrels or $2,000,000 worth of a product). To ensure that the producer does not exceed this production-output limit, information about produced and/or sold amounts can be stored on a distributed ledger. This provides public verifiability. Everyone who has access to the distributed ledger (e.g., consumers, governmental authorities or non-governmental organizations) can read each of the produced amounts, sum them up, and compare the resulting amount to the producer's overall quota.
While this approach ensures transparency and enables verifiability, it may be associated with some disadvantages. For example, such a technique may reveal details about a final product such as, depending on the industry, a recipe (e.g., single ingredients or amounts of medicine in pharmaceutical industry). That is, this form of publicly verifiable mass balancing does not preserve any privacy and could adversely impact a producer's competitive advantage. Furthermore, this type of non-privacy-preserving storage of customer data in a distributed ledger might conflict with legal regulations, such as the General Data Protection Regulations (“GDPR”) of the European Union.
It would therefore be desirable to provide an improved mass balancing protocol in an automatic and efficient manner.
According to some embodiments, methods and systems may be associated with a producer who supplies amounts xi of a good to a plurality of consumers Ci in a series of transactions and is subject to a mass balancing verification protocol after every K transactions. A producer platform may compute K random shares (r1 through rK) of a random value r, publish blinded amounts ti representing xi+ri to a secure, distributed transaction ledger, and transmit an encrypted ri to consumer Ci using an asymmetric cryptosystem. A consumer platform may receive and decrypt ri directly from the producer platform as well as an amount {circumflex over (x)}i of the good in the physical world. The consumer platform may compute {circumflex over (x)}i+ri and generate a fraud alert signal if it differs from the blinded amount ti of the good that was published to the secure, distributed transaction ledger by the producer platform. The consumer platform may also transmit an encrypted rolling sum value to a next consumer Ci+1. A verifier platform may, after K transactions, execute the mass balance verification protocol to determine a total amount of the good that the producer had collectively supplied to the consumers Ci. The verifier platform may also generate a fraud alert signal when appropriate based on the total amount and a maximum allowed amount.
Some embodiments comprise: means for computing K random shares (r1 through rK) of a random value r; means for publishing blinded amounts ti representing xi+ri to a secure, distributed transaction ledger using additive secret sharing to store information associated with amounts xi in a privacy-preserving form; means for transmitting an encrypted ri to consumer Ci using an asymmetric cryptosystem; means for receiving, at a consumer platform of consumer Ci, the encrypted ri from the producer platform while the consumer Ci actually receives an amount {circumflex over (x)}i of the good from the producer; means for executing, by the consumer platform, a decryption algorithm to determine ri; means for computing {circumflex over (x)}i+ri and generating, by the consumer platform, a fraud alert signal if it differs from the published ti; means for transmitting an encrypted rolling sum value to a next consumer Ci+1; means for executing, by a verifier platform after K transactions, the mass balance verification protocol to determine a total amount of good that the producer had collectively supplied to the consumers Ci; and means for generating, by the verifier platform, a fraud alert signal when appropriate based on the total amount and a maximum allowed amount.
Some technical advantages of some embodiments disclosed herein are improved systems and methods to provide an improved mass balancing protocol in an automatic and efficient manner.
In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of embodiments. However, it will be understood by those of ordinary skill in the art that the embodiments may be practiced without these specific details. In other instances, well-known methods, procedures, components and circuits have not been described in detail so as not to obscure the embodiments.
One or more specific embodiments of the present invention will be described below. In an effort to provide a concise description of these embodiments, all features of an actual implementation may not be described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure.
Some embodiments described herein provide a mechanism that allows for public verifiability in mass balancing scenarios and ensures privacy of the producer's production details such as amounts. The mechanism may be based on an information security technology referred to as “additive secret sharing.” As a result, a system may store single data points, e.g., amounts, on a distributed ledger in a way that preserves privacy. The data held by the distributed ledger might not reveal anything about the single amounts but still allows for public verifiability of an overall sum of produced amounts. This, in turn, may enable comparison to a producer's quota.
Some embodiments disclosed herein may utilize an asymmetric cryptosystem. As used herein, the phrase “asymmetric cryptosystem” (also known as “public-key cryptography”) may refer to a cryptographic system that uses pairs of keys, including: (1) public keys, which may be disseminated widely; and (2) private keys, which are known only to the owner. The generation of such keys may depend on cryptographic algorithms (e.g., based on mathematical problems) to produce one-way functions. Effective security then only requires keeping the private key private, and the public key can be openly distributed without compromising security. In such a system, any person can encrypt a message using the receiver's public key, but that encrypted message can only be decrypted with the receiver's private key. In some cases, authentication may also be provided. For example, a sender may combine a message with a private key to create a short digital signature associated with the message. Anyone with the sender's corresponding public key can then combine the same message and a potential digital signature associated with it to determine if the signature is valid (i.e., made by the owner of the corresponding private key).
An asymmetric cryptosystem may be associated with a tuple S=(G, E, D) consisting of three polynomial-time algorithms:
Some embodiments described herein may utilize additive secret sharing. As used herein, the phrase “additive secret sharing” may refer to a party that wants to split a secret into several shares given to shareholders, in such a way that each individual shareholder does not know the secret, yet if enough shareholders re-combine their shares then the secret can be reconstructed.
Some embodiments described herein may utilize one or more secure, distributed transaction ledgers. As used herein, the phrase “distributed ledger” (also called a shared ledger or distributed ledger technology) may refer to a consensus of replicated, shared, and synchronized digital data that might be geographically spread across multiple sites, countries, or institutions without incorporating a central administrator or centralized data storage. A peer-to-peer network and consensus algorithms may help ensure accurate replication. For example, a distributed ledger database might be spread across several nodes (e.g., devices) on a peer-to-peer network, and each node may replicate and save an identical copy of the ledger (updating itself independently). When a ledger update happens, each node may construct the new transaction and the nodes may vote by consensus algorithm on which copy is correct. Once a consensus has been determined, all of the nodes update themselves with the new, correct copy of the ledger. Security may be accomplished through cryptographic keys and signatures. As long as most of the nodes are honest, such a secure, distributed ledger will ensure data integrity. One very common form of distributed ledger is blockchain technology (e.g., associated with a public or private blockchain).
As used herein, devices, including those associated with the system 200 and any other device described herein, may exchange information via any communication network which may be one or more of a Local Area Network (“LAN”), a Metropolitan Area Network (“MAN”), a Wide Area Network (“WAN”), a proprietary network, a Public Switched Telephone Network (“PSTN”), a Wireless Application Protocol (“WAP”) network, a Bluetooth network, a wireless LAN network, and/or an Internet Protocol (“IP”) network such as the Internet, an intranet, or an extranet. Note that any devices described herein may communicate via one or more such communication networks.
The producer platform 210 and/or the other devices in the system 200 may store information into and/or retrieve information from various data stores (e.g., data storage devices), which may be locally stored or reside remote from the producer platform 210 and/or the other devices. Although a single producer platform 210 and verifier platform 290 are shown in
A user or administrator may access the system 200 via a remote device (e.g., a Personal Computer (“PC”), tablet, or smartphone) to view information about and/or manage operational information in accordance with any of the embodiments described herein. In some cases, an interactive graphical user interface display may let an operator or administrator define and/or adjust certain parameters (e.g., to configure quota rules or requirements, add consumers, etc.) and/or provide or receive automatically generated recommendations or results from the system 200.
The methods of
The information transmitted at S316 may then be evaluated by the consumer Ci. For example,
For simplification purposes, assume that a single producer P transfers amounts xi of a particular good to consumers Ci. These amounts are published via a distributed ledger DL in a privacy-preserving form. Each of these entries can be verified by the respective consumer Ci. This may be referred to as “single amount verification.” Furthermore, the producer P tries to convince verifier V that the total amount x=Σi xi does not exceed a maximum xmax (e.g., a threshold quota). This maximum amount xmax of a good that producer P is entitled to produce is public information. This verification may be referred to as “balance verification.”
Also assume that every consumer Ci has an individual key pair (pki, ski) of an asymmetric cryptosystem, consisting of a public encryption key pki and a secret decryption key ski. Applying the encryption function Epk
Further assume a balance verification frequency of once every K produced amounts. At the beginning of each K-cycle, P secret-shares a random value r by computing K random shares such that r1=r1, . . . , rK=rK of r such that r=Σi=1K ri.
The protocol specification includes an amount publication that begins with the producer P blinding the amount xi by adding the i-th random share ri. Producer P then publishes the resulting blinded value ti via the distributed ledger DL as follows:
P→DL:ti=xi+ri
The amount publication then has producer P encrypt ri with consumer Ci's public key and send the resulting ciphertext si to consumer Ci as follows:
P→Ci:si=Epk
Next, the protocol specification performs single amount verification. Initially, consumer Ci decrypts si and obtains the random blinding share ri used for blinding as follows:
Ci:ri=Dsk
Next in the single amount verification, consumer Ci adds the decrypted ri to the (physically) received amount {circumflex over (x)}i and verifies ti by comparing it to this sum. If the two values are not equal, consumer Ci reports fraud as follows:
Ci:ti{circumflex over (x)}i+ri
a) if ti≠{circumflex over (x)}i+ri: report fraud (producer dishonest)
Finally, the single amount verification performs the following to allow for removing the overall blinding r=Σi ri later during balance verification, the consumers maintain the sum rΣ of the used ri. To do so, each consumer Ci sends rΣ to the consumer Ci+1 of the next transaction. To prevent consumer C2 from learning r1, consumer C1 blinds r1 with a randomly chosen r0. The sum rΣ is transferred in an encrypted form from consumer Ci to consumer Ci+1 to prevent uninvolved participants from inferring ri by comparing two consecutive rΣ as follows:
Ci→Ci+1:
a) If i=1: Epk
b) If 1<i<K: Epk
c) If i=K: Epk
Next, the protocol specification performs balance verification. Initially the balance verification, after K produced amounts (i.e., at the end of a K-cycle or “epoch”), consumer C1 subtracts r0 from the blinded sum rΣ of random values ri to obtain the unblinded sum. The unblinded sum of the j-th K-cycle is denoted by rΣ
C1→DL: if i=K:rΣ
Balance verification then involves, once every K produced amounts (i.e., once i=K), verifier V computes the balance by adding all ti and subtracting their sum from the maximum amount xmax. The random shares ri (used in each ti=xi+ri) of each K-cycle add up to rΣ=r. Therefore, the rΣ
V: δj=xmax−Σiti+ΣjrΣ
a) If δj<0: report fraud (mass balance exceeded)
b) If δj=0: report fraud once P publishes another ti
For recurring balance verification, a verifier V might speed up the calculation of δj by caching the balance after every K-cycle (either locally by each verifier V or on distributed ledger DL) and thus achieve a number of additions that is independent of the number of previous K-cycles. To do so, when computing δj the verifier V may subtract the ti of the current K-cycle from the previous balance δj−1 and add rΣ
Furthermore, according to some embodiments producer P could secret-share r=0 instead of some random r. This may simplify the balance computation because the random ri of a K-cycle will cancel out automatically (assuming that the producer P always behaves in an honest fashion during secret sharing).
Note that any communication between producers P and consumers C (or between consumers C and other consumers C) might be performed via direct communication channels and/or through the distributed ledger DL.
Note that the embodiments described herein may also be implemented using any number of different hardware configurations. For example,
The processor 510 also communicates with a storage device 530. The storage device 530 may comprise any appropriate information storage device, including combinations of magnetic storage devices (e.g., a hard disk drive), optical storage devices, mobile telephones, and/or semiconductor memory devices. The storage device 530 stores a program 512 and/or a verification engine 514 for controlling the processor 510. The processor 510 performs instructions of the programs 512, 514, and thereby operates in accordance with any of the embodiments described herein. For example, when the platform 500 is associated with a producer the processor 510 may compute K random shares (r1 through rK) of a random value r, publish blinded amounts ti representing xi+ri to a secure, distributed transaction ledger using additive secret sharing to store information associated with amounts xi in a privacy-preserving form, and transmit an encrypted ri to consumer Ci using an asymmetric cryptosystem. When the platform 500 is associated with a consumer, the processor 510 may receive the encrypted ri from the producer platform (while the consumer Ci actually receives an amount {circumflex over (x)}i of the good from the producer), execute a decryption algorithm to determine ri, and compute {circumflex over (x)}i+ri and generate a fraud alert signal if differs from the published ti. The processor 510 may also transmit an encrypted rolling sum value to a next consumer Ci+1. When the platform 500 is associated with a verifier, the processor 510 may execute a mass balance verification protocol to determine a total amount of good that the producer had collectively supplied to the consumers Ci. The processor 510 may also generate a fraud alert signal when appropriate based on the total amount and a maximum allowed amount (e.g., a production quota).
The programs 512, 514 may be stored in a compressed, uncompiled and/or encrypted format. The programs 512, 514 may furthermore include other program elements, such as an operating system, clipboard application, a database management system, and/or device drivers used by the processor 510 to interface with peripheral devices.
As used herein, information may be “received” by or “transmitted” to, for example: (i) the platform 500 from another device; or (ii) a software application or module within the platform 500 from another software application, module, or any other source.
In some embodiments (such as the one shown in
Referring to
The transaction identifier and date 602 might be a unique alphanumeric label that is associated with a transaction between a producer and a consumer along with a date that the transaction was executed. The producer identifier and quota 604 might identify who supplied the good to the consumer (along with any mass balance limits associated with that type of good). The consumer identifier 606 might identify who received the good and the transaction verified indication 608 might indicate whether or not that party has verified that the producer reported the correct amount (as compared to the physical amount that was received). The fraud signal 610 might indicate that the system has detected that the producer has exceeded the associated quote (along with the actual total amount of good that was provided by the producer to all of the consumers in aggregate without revealing exactly how much each consumer received individually).
Thus, embodiments may let the data required for mass balancing be kept confidential. Instead, the information is made available in a privacy preserving way. This enables novel business scenarios for distributed ledgers, such as blockchains, where confidentiality can play a substantial role. Furthermore, by using additive secret sharing, embodiments may not only help ensure confidentiality but may also reduce computational complexity (encouraging good scalability). Furthermore, embodiments may enable a variety of use cases based on latest technologies (e.g., distributed ledgers and/or blockchain as well as secret sharing) to improve analytics and intelligent processes in enterprise applications.
Although specific hardware and data configurations have been described herein, note that any number of other configurations may be provided in accordance with some embodiments of the present invention (e.g., some of the information associated with the databases described herein may be combined or stored in external systems). Moreover, although some embodiments are focused on particular types of producers, consumers, and goods, any of the embodiments described herein could be applied to other types of applications. For example, a protocol might help ensure that a single consumer does not exceed an overall quota limiting how much of a particular type of good they are allowed purchase from various producers (without revealing how much each producer individually sold to that consumer).
Moreover, the displays shown herein are provided only as examples, and any other type of user interface could be implemented. For example,
The present invention has been described in terms of several embodiments solely for the purpose of illustration. Persons skilled in the art will recognize from this description that the invention is not limited to the embodiments described, but may be practiced with modifications and alterations limited only by the spirit and scope of the appended claims.
Number | Name | Date | Kind |
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20180137512 | Georgiadis | May 2018 | A1 |
20200259828 | Shaffer | Aug 2020 | A1 |
Number | Date | Country |
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1656600 | Jun 2017 | EP |
Number | Date | Country | |
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20210327002 A1 | Oct 2021 | US |