WO2020233628A1 - 结合事件函数类型和判断条件的收据存储方法和节点 - Google Patents

结合事件函数类型和判断条件的收据存储方法和节点 Download PDF

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Publication number
WO2020233628A1
WO2020233628A1 PCT/CN2020/091403 CN2020091403W WO2020233628A1 WO 2020233628 A1 WO2020233628 A1 WO 2020233628A1 CN 2020091403 W CN2020091403 W CN 2020091403W WO 2020233628 A1 WO2020233628 A1 WO 2020233628A1
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transaction
log
event function
smart contract
blockchain node
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PCT/CN2020/091403
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English (en)
French (fr)
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刘琦
闫莺
魏长征
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创新先进技术有限公司
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    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06Q—INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL OR SUPERVISORY PURPOSES; SYSTEMS OR METHODS SPECIALLY ADAPTED FOR ADMINISTRATIVE, COMMERCIAL, FINANCIAL, MANAGERIAL OR SUPERVISORY PURPOSES, NOT OTHERWISE PROVIDED FOR
    • G06Q20/00—Payment architectures, schemes or protocols
    • G06Q20/38—Payment protocols; Details thereof
    • G06Q20/382—Payment protocols; Details thereof insuring higher security of transaction
    • G06Q20/3823—Payment protocols; Details thereof insuring higher security of transaction combining multiple encryption tools for a transaction

Definitions

  • One or more embodiments of the present specification relate to the field of blockchain technology, and in particular to a receipt storage method and node that combine event function types and judgment conditions.
  • Blockchain technology is built on a transmission network (such as a peer-to-peer network).
  • the network nodes in the transmission network use chained data structures to verify and store data, and use distributed node consensus algorithms to generate and update data.
  • TEE Trusted Execution Environment
  • TEE can play the role of a black box in the hardware. Neither the code executed in the TEE nor the data operating system layer can be peeped. Only the pre-defined interface in the code can operate on it.
  • plaintext data is calculated in TEE instead of complex cryptographic operations in homomorphic encryption. There is no loss of efficiency in the calculation process. Therefore, the combination with TEE can achieve less performance loss. Under the premise, the security and privacy of the blockchain are greatly improved. At present, the industry is very concerned about TEE solutions.
  • TEE solutions including TPM (Trusted Platform Module) for software and Intel SGX (Software Guard Extensions) for hardware. , Software Protection Extension), ARM Trustzone (trust zone) and AMD PSP (Platform Security Processor, platform security processor).
  • one or more embodiments of this specification provide a receipt storage method and node that combine event function types and judgment conditions.
  • a receipt storage method combining event function type and judgment condition including:
  • the first blockchain node receives the encrypted transaction calling the smart contract
  • the first blockchain node decrypts the transaction in a trusted execution environment to obtain the smart contract, and the smart contract includes a special event function;
  • the first blockchain node executes the smart contract in the trusted execution environment to obtain receipt data, where the receipt data includes a log corresponding to the special event function;
  • the first blockchain node stores the receipt data so that at least one log field that meets a preset condition in the log corresponding to the special event function is stored in plain text, and the rest of the receipt data is stored in cipher text.
  • a receipt storage node combining event function type and judgment condition including:
  • the receiving unit receives the encrypted transaction that calls the smart contract
  • a decryption unit decrypting the transaction in a trusted execution environment to obtain the smart contract, the smart contract including a special event function
  • the storage unit stores the receipt data so that at least one log field that meets a preset condition in the log corresponding to the special event function is stored in plain text, and the rest of the receipt data is stored in cipher text.
  • an electronic device including:
  • a memory for storing processor executable instructions
  • the processor implements the method according to the first aspect by running the executable instruction.
  • a computer-readable storage medium is provided, and computer instructions are stored thereon, which, when executed by a processor, implement the steps of the method described in the first aspect.
  • Fig. 1 is a schematic diagram of creating a smart contract according to an exemplary embodiment.
  • Fig. 2 is a schematic diagram of invoking a smart contract provided by an exemplary embodiment.
  • Fig. 3 is a flowchart of a receipt storage method combining event function type and judgment condition provided by an exemplary embodiment.
  • Fig. 4 is a schematic diagram of implementing privacy protection on blockchain nodes according to an exemplary embodiment.
  • Fig. 5 is a schematic diagram of the functional logic of implementing a blockchain network through a system contract and a chain code provided by an exemplary embodiment.
  • Fig. 6 is a block diagram of a receipt storage node combining event function type and judgment condition provided by an exemplary embodiment.
  • the steps of the corresponding method may not be executed in the order shown and described in this specification.
  • the method includes more or fewer steps than described in this specification.
  • a single step described in this specification may be decomposed into multiple steps for description in other embodiments; and multiple steps described in this specification may also be combined into a single step in other embodiments. description.
  • Blockchain is generally divided into three types: Public Blockchain, Private Blockchain and Consortium Blockchain.
  • the most decentralized one is the public chain.
  • the public chain is represented by Bitcoin and Ethereum. Participants who join the public chain can read the data records on the chain, participate in transactions, and compete for the accounting rights of new blocks. Moreover, each participant (ie, node) can freely join and exit the network, and perform related operations.
  • the private chain is the opposite.
  • the write permission of the network is controlled by an organization or institution, and the data read permission is regulated by the organization.
  • the private chain can be a weakly centralized system with strict restrictions and few participating nodes. This type of blockchain is more suitable for internal use by specific institutions.
  • the alliance chain is a block chain between the public chain and the private chain, which can achieve "partial decentralization".
  • Each node in the alliance chain usually has a corresponding entity or organization; participants are authorized to join the network and form a stakeholder alliance to jointly maintain the operation of the blockchain.
  • a smart contract on the blockchain is a contract that can be triggered and executed by a transaction on the blockchain system.
  • Smart contracts can be defined in the form of codes.
  • EVM Ethereum Virtual Machine
  • bytecode virtual machine code
  • the EVM of node 1 can execute the transaction and generate a corresponding contract instance.
  • "0x6f8ae93" in the figure 1 represents the address of this contract, the data field of the transaction can be stored in bytecode, and the to field of the transaction is empty.
  • the contract is successfully created and can be called in the subsequent process.
  • a contract account corresponding to the smart contract appears on the blockchain and has a specific address, and the contract code will be stored in the contract account.
  • the behavior of the smart contract is controlled by the contract code.
  • smart contracts enable virtual accounts containing contract codes and account storage (Storage) to be generated on the blockchain.
  • the EVM of a certain node can execute the transaction and generate a corresponding contract instance.
  • the from field of the transaction in Figure 2 is the address of the account of the transaction initiator (ie Bob), the "0x6f8ae93" in the to field represents the address of the called smart contract, and the value field in Ethereum is the value of Ether ,
  • the method and parameters of calling the smart contract are stored in the data field of the transaction. Smart contracts are executed independently on each node in the blockchain network in a prescribed manner. All execution records and data are stored on the blockchain, so when the transaction is completed, the blockchain will be stored on the blockchain that cannot be tampered with. Lost transaction certificate.
  • the receipt data obtained by a node executing a transaction can include the following:
  • the Result field indicates the execution result of the transaction
  • the Gas used field indicates the gas value consumed by the transaction
  • the Logs field indicates the log generated by the transaction.
  • the log can further include the From field, To field, Topic field, and Log data field, among which the From field indicates the account address of the initiator of the call, and the To field indicates the called object (such as a smart contract)
  • the account address and Topic field indicate the subject of the log, and the Log data field indicates the log data;
  • the Output field indicates the output of the transaction.
  • log is a function provided in Ethereum.
  • the logs generated by each event contained in the code can be recorded.
  • the log allows to record the details of the event.
  • the From and To fields mentioned above can indicate the accounts of both parties involved in the transaction, and the Topic field can contain the value of the state variables referenced by the event after the code is executed, etc. Therefore, not only can the log be used as relevant evidence after the transaction is executed on the blockchain, it can also be used to drive related operations.
  • the callback function of JavaScript can be used to monitor events, and the corresponding log can be generated when the event is triggered. Therefore, by retrieving the log content, the DAPP (Decentralized Application) client can be driven to perform related execution when the preset log content is retrieved Processing operations, etc.
  • DAPP Decentralized Application
  • the block chain is a data set stored in a database of a node and organized by a specific logic.
  • the database as described later, may be a storage medium, such as a persistent storage medium, on a physical carrier.
  • Step 302 The first blockchain node receives the encrypted transaction for invoking the smart contract.
  • the user can directly generate a transaction on the first blockchain node; or, the user can generate a transaction on the client, and send the transaction to the first blockchain node through the client; or, the client
  • the terminal can send the above transaction to the second blockchain node, and the second blockchain node sends the transaction to the first blockchain node.
  • the transaction content may include the account address of the smart contract being called, the methods and parameters that need to be passed in, and so on.
  • Step 304 The first blockchain node decrypts the transaction in a trusted execution environment to obtain the smart contract, and the smart contract includes a special event function.
  • the smart contract may include one or more events, and each event is used to implement predefined related processing logic. After each event contained in the smart contract is called and executed, the corresponding Logs field will be generated. For example, when the smart contract contains event 1 and event 2, event 1 can generate the corresponding Logs field, and event 2 can generate the corresponding Logs field. , So that the receipt data corresponding to the smart contract contains multiple Logs fields at the same time.
  • the events contained in the smart contract can be divided into special event functions and ordinary event functions.
  • the logs generated by the ordinary event functions are stored in cipher text to achieve privacy protection; the special event functions generated Logs need to store at least part of the log fields (such as the exposed log fields below) in plain text on the premise of meeting the privacy protection requirements, so that the content of this part of the log fields can be retrieved to drive the implementation of related operations .
  • the special event function may be a predefined global event function in the blockchain network.
  • the event function belonging to the "special event function” can be recorded, for example, it can be recorded in the special event function list; accordingly, by combining the event function contained in the smart contract with By comparing the above special event function list, it can be determined whether the event function included in the smart contract is the above special event function.
  • the special event function can be any function defined in the smart contract, and by adding a type identifier for the event function in the smart contract, the event function can be marked as a special event function.
  • the code example of the event function included in the smart contract is as follows:
  • Event buy_candy1 expose(who,candy_num);
  • the smart contract defines 2 events: event buy_candy1 and event buy_candy2.
  • event buy_candy1 By adding the type identifier "expose" to the event buy_candy1, the event buy_candy1 can be marked as the above special event function; correspondingly, since the event buy_candy2 does not contain the type identifier "expose", the event buy_candy2 is a normal event function Instead of the special event function mentioned above.
  • High-level languages supported by Ethereum such as Solidity, Serpent, and LLL languages
  • a smart contract written in a high-level language can be compiled into a corresponding bytecode through a compiler, and the first blockchain node will finally execute the smart contract in the form of bytecode in the EVM virtual machine.
  • the above-mentioned type identifier can be the same in high-level language and bytecode smart contract code, or the first type identifier in high-level language smart contract code, and the second type in bytecode smart contract code Type identifier, the first type identifier and the second type identifier can correspond to each other.
  • the encrypted transaction can be kept in a state of privacy protection, and the transaction content can be prevented from being exposed.
  • the transaction content may contain information such as the account address of the transaction initiator and the account address of the transaction target. Encryption processing can ensure that these transaction contents cannot be directly read.
  • the above-mentioned transaction may be encrypted by a symmetric encryption algorithm, or it may be encrypted by an asymmetric algorithm.
  • the encryption algorithm used by symmetric encryption such as DES algorithm, 3DES algorithm, TDEA algorithm, Blowfish algorithm, RC5 algorithm, IDEA algorithm, etc.
  • Asymmetric encryption algorithms such as RSA, Elgamal, knapsack algorithm, Rabin, D-H, ECC (elliptic curve encryption algorithm), etc.
  • the foregoing transaction may be encrypted by a combination of a symmetric encryption algorithm and an asymmetric encryption algorithm.
  • the client can use a symmetric encryption algorithm to encrypt the transaction content, that is, use the symmetric encryption algorithm key to encrypt the transaction content, and use an asymmetric encryption algorithm to encrypt the symmetric encryption algorithm
  • the key used for example, the key used in the public key encryption symmetric encryption algorithm using an asymmetric encryption algorithm.
  • the first blockchain node After the first blockchain node receives the encrypted transaction, it can first decrypt it with the private key of the asymmetric encryption algorithm to obtain the key of the symmetric encryption algorithm, and then decrypt it with the key of the symmetric encryption algorithm to obtain the transaction content.
  • a transaction When a transaction is used to call a smart contract, it can be a call of multiple nested structures. For example, the transaction directly calls smart contract 1, and the code of smart contract 1 calls smart contract 2, and the code in smart contract 2 points to the contract address of smart contract 3, so that the transaction actually calls the code of smart contract 3 indirectly , And smart contract 3 includes a certain event function. In this way, it is equivalent to the event function included in smart contract 1.
  • the specific implementation process is similar to the above process, and will not be repeated here.
  • Step 306 The first blockchain node executes the smart contract in the trusted execution environment to obtain receipt data, where the receipt data includes a log corresponding to the special event function.
  • a corresponding Logs field will be generated, that is, a log corresponding to each event function will be generated.
  • the log corresponding to the special event function can be further determined, and when at least a part of the log fields corresponding to the special event function meets the preset condition, the at least part of the log fields are allowed to be stored in plain text.
  • the first blockchain node after receiving a transaction invoking a smart contract from a client, the first blockchain node can check whether the transaction is valid, the format is correct, and the signature of the transaction is legal.
  • the nodes in Ethereum are generally nodes that compete for the right to bookkeeping. Therefore, the first blockchain node as the node that competes for the right to bookkeeping can execute the transaction locally. If one of the nodes competing for the accounting right wins in the current round of the accounting right, it becomes the accounting node. If the first blockchain node wins this round of competition for accounting rights, it becomes the accounting node; of course, if the first blockchain node does not win in this round of competition for accounting rights, it is not Accounting nodes, and other nodes may become accounting nodes.
  • a smart contract is similar to a class in object-oriented programming.
  • the result of execution generates a contract instance corresponding to the smart contract, similar to the object corresponding to the generated class.
  • the process of executing the code used to create a smart contract in a transaction will create a contract account and deploy the contract in the account space.
  • the address of the smart contract account is generated from the sender's address ("0xf5e -- in Figure 1-2) and the transaction nonce (nonce) as input, and is generated by an encryption algorithm, such as in Figure 1-2
  • the contract address "0x6f8ae93" is generated from the sender's address "0xf5e" and the nonce in the transaction through an encryption algorithm.
  • consensus algorithms such as Proof of Work (POW), Proof of Stake (POS), and Delegated Proof of Stake (DPOS) are adopted in blockchain networks that support smart contracts. All nodes competing for the right to account can execute the transaction after receiving the transaction including the creation of a smart contract. One of the nodes competing for the right to bookkeeping may win this round and become the bookkeeping node.
  • the accounting node can package the transaction containing the smart contract with other transactions and generate a new block, and send the generated new block to other nodes for consensus.
  • the nodes with the right to book accounts have been agreed before this round of bookkeeping. Therefore, after the first blockchain node receives the above transaction, if it is not the accounting node of this round, it can send the transaction to the accounting node.
  • accounting nodes which can be the first blockchain node
  • the accounting node packages the transaction (or other transactions together) and generates a new block
  • the generated new block or block header is sent to other nodes for consensus.
  • the accounting nodes in this round can package and package the transaction. Generate a new block, and send the header of the generated new block to other nodes for consensus. If other nodes receive the block and verify that there is no problem, they can append the new block to the end of the original block chain to complete the accounting process and reach a consensus; if the transaction is used to create a smart contract, then The deployment of the smart contract on the blockchain network is completed. If the transaction is used to call the smart contract, the call and execution of the smart contract are completed. In the process of verifying the new block or block header sent by the accounting node, other nodes may also execute the transaction in the block.
  • the execution process can generally be executed by a virtual machine. Taking Ethereum as an example, it supports users to create and/or call some complex logic in the Ethereum network. This is the biggest challenge that distinguishes Ethereum from Bitcoin blockchain technology.
  • the core of Ethereum as a programmable blockchain is the Ethereum Virtual Machine (EVM), and every Ethereum node can run EVM.
  • EVM is a Turing complete virtual machine, which means that various complex logic can be implemented through it. Users publish and call smart contracts in Ethereum run on the EVM.
  • the first blockchain node can execute the decrypted smart contract code in a Trusted Execution Environment (TEE).
  • TEE Trusted Execution Environment
  • the first blockchain node can be divided into a regular execution environment (on the left in the figure) and TEE, and transactions submitted by the client (as described above, transactions can have other sources; here, the client submits Take the transaction as an example to illustrate)
  • First enter the "transaction/query interface" in the regular execution environment for identification.
  • Transactions that do not require privacy processing can be left in the regular execution environment for processing (here can be based on the user type of the transaction initiator , Transaction type, identifier contained in the exchange, etc.
  • TEE is isolated from the conventional execution environment.
  • the transaction is encrypted before entering the TEE, and it is decrypted into the transaction content in the clear in the trusted execution environment, so that the transaction content in the clear text can be efficiently processed in the TEE and in the TEE under the premise of ensuring data security.
  • the receipt data in plaintext is generated in.
  • TEE is a secure extension based on CPU hardware and a trusted execution environment completely isolated from the outside.
  • TEE was first proposed by Global Platform to solve the security isolation of resources on mobile devices, and parallel to the operating system to provide a trusted and secure execution environment for applications.
  • ARM's Trust Zone technology is the first to realize the real commercial TEE technology.
  • security requirements are getting higher and higher.
  • Not only mobile devices, cloud devices, and data centers have put forward more needs for TEE.
  • the concept of TEE has also been rapidly developed and expanded. Compared with the originally proposed concept, TEE is a broader TEE. For example, server chip manufacturers Intel, AMD, etc. have successively introduced hardware-assisted TEE and enriched the concept and characteristics of TEE, which has been widely recognized in the industry.
  • Intel Software Protection Extensions (SGX) and other TEE technologies isolate code execution, remote attestation, secure configuration, secure storage of data, and trusted paths for code execution.
  • the applications running in the TEE are protected by security and are almost impossible to be accessed by third parties.
  • SGX provides an enclave (also called an enclave), which is an encrypted trusted execution area in the memory, and the CPU protects data from being stolen.
  • enclave also called an enclave
  • the CPU protects data from being stolen.
  • a part of the area EPC Enclave Page Cache, enclave page cache or enclave page cache
  • the encryption engine MEE Memory Encryption Engine
  • SGX users can distrust the operating system, VMM (Virtual Machine Monitor), and even BIOS (Basic Input Output System). They only need to trust the CPU to ensure that private data will not leakage.
  • the private data can be encrypted and transmitted to the circle in cipher text, and the corresponding secret key can also be transmitted to the circle through remote certification. Then, the data is used for calculation under the encryption protection of the CPU, and the result will be returned in ciphertext. In this mode, you can use powerful computing power without worrying about data leakage.
  • the transaction contains the code of the smart contract
  • the first blockchain node can decrypt the transaction in the TEE to obtain the code of the smart contract contained therein, and then Execute this code in TEE.
  • the first blockchain node can execute the code in the TEE (if the called smart contract handles the encryption state, the smart contract needs to be executed in the TEE first. Decrypt to get the corresponding code).
  • the first blockchain node may use the newly added processor instructions in the CPU to allocate a part of the area EPC in the memory, and encrypt the above-mentioned plaintext code and store it in the EPC through the encryption engine MEE in the CPU.
  • the encrypted content in EPC is decrypted into plain text after entering the CPU.
  • the plaintext code for executing smart contracts can load the EVM into the enclosure.
  • the key management server can calculate the hash value of the local EVM code and compare it with the hash value of the EVM code loaded in the first blockchain node. The correct comparison result is a necessary condition for passing remote certification. , So as to complete the measurement of the code loaded in the SGX circle of the first blockchain node. After measurement, the correct EVM can execute the above smart contract code in SGX.
  • Step 308 The first blockchain node stores the receipt data so that at least one log field that meets a preset condition in the log corresponding to the special event function is stored in plain text, and the rest of the receipt data is stored in cipher text. Form storage.
  • all log fields of the log can be compared with corresponding preset conditions, and all log fields that meet the preset conditions are stored in plain text .
  • log fields corresponding to special event functions but satisfying preset conditions, logs corresponding to ordinary event functions, and other receipt contents in receipt data are all stored in cipher text.
  • the exposure log field corresponding to the special event function can be determined, and the exposure log field can be compared with the corresponding preset conditions, so as to satisfy the preset
  • the exposure log field of the condition is stored in clear text.
  • Exposure log fields often involve relatively little privacy content, or do not involve core privacy content, and the risk of storing in plaintext is relatively low; non-exposed log fields may involve relatively more or relatively more important privacy content. Storing in cipher text can ensure that it does not deviate from the core purpose of privacy protection. By judging in combination with preset conditions, it is possible to further filter out the private content that may be contained in the exposed log fields that are not suitable for disclosure, so as to ensure that the retrieval operation can be completed while achieving privacy protection as much as possible.
  • the special event function includes an exposure log field indicated by an exposure identifier.
  • the first blockchain node can read the exposure identifier contained in the special event function, and determine one or more log fields marked by the exposure identifier as the aforementioned exposed log field.
  • the code examples of the special event functions included in the smart contract are as follows:
  • Event buy_candy4 show_to(who,candy_num);
  • the smart contract defines 2 events: event buy_candy3 and event buy_candy4.
  • the event buy_candy3 contains the type identifier "expose”. According to the above, the event buy_candy3 can be determined as a special event function. Further, after the type identifier "expose”, the exposure identifier "_from” is included, and the exposure identifier "_from” is used to indicate the log field From, so that in the log Logs generated corresponding to the event buy_candy3, the From field will be in plain text Store, and the remaining To field, Topic field, Log data field, etc. are stored in cipher text.
  • the event buy_candy4 does not contain the type identifier "expose”; however, if the event buy_candy4 is the aforementioned predefined special event function, for example, the event buy_candy4 is in the aforementioned special event function list, then it can be determined that the event buy_candy4 is a special event function. Further, the event buy_candy4 contains the exposed identifier "show_to", which is used to indicate the log field to, so that in the log Logs generated corresponding to the event buy_candy4, the To field will be stored in plain text, and the rest The From field, Topic field, Log data field, etc. are stored in cipher text.
  • the special event function can include the encrypted log field indicated by the encrypted identifier, and the exposed log field is the remaining log fields.
  • the code examples of the special event functions included in the smart contract are as follows:
  • Event buy_candy5 expose_hide_from(who,candy_num);
  • the smart contract defines 2 events: event buy_candy5 and event buy_candy6.
  • the event buy_candy5 contains the type identifier "expose”. According to the above, the event buy_candy5 can be determined as a special event function. Further, after the type identifier "expose”, the encrypted identifier "hide_from” is included. The encrypted identifier "hide_from” is used to indicate the log field From, so that in the log Logs generated corresponding to the event buy_candy5, the From field will be in cipher text Stored in the form, and the remaining To field, Topic field, Log data field, etc. are exposed log fields, which are all stored in plain text.
  • the event buy_candy6 does not contain the type identifier "expose”; however, if the event buy_candy6 is the aforementioned predefined special event function, for example, the event buy_candy6 is in the aforementioned special event function list, then it can be determined that the event buy_candy6 is a special event function. Further, the event buy_candy6 contains the encrypted identifier "hide_to", which is used to indicate the log field to, so that in the log Logs generated corresponding to the event buy_candy6, the To field will be stored in cipher text, and the rest The From field, Topic field, Log data field, etc. are exposed log fields, which are all stored in plain text.
  • the above-mentioned exposure/encryption identifier can be the same in high-level language and bytecode smart contract code, or the first exposure/encryption identifier in high-level language smart contract code, and the smart contract code in bytecode form is
  • the second exposure/encryption identifier, the first exposure/encryption identifier and the second exposure/encryption identifier may correspond to each other.
  • the mapping relationship between the special event function and the exposure log field, or the special event function and the encrypted log can be predefined
  • the mapping relationship between the fields allows the first blockchain node to obtain the predefined mapping relationship, and determine the exposure log field corresponding to the special event function according to the special event function included in the smart contract and the above mapping relationship.
  • mapping relationship includes “Event buy_candy7-from_to", “Event buy_candy8-topic” and other content
  • the above mapping relationship "Event buy_candy7-from_to” can be queried. Then it can be determined that the exposure log fields corresponding to the event "Event buy_candy7" are the From field and the To field. If the event "Event buy_candy8" is included in the smart contract, the above mapping relationship "Event buy_candy8-topic" can be found by querying The exposure log field corresponding to the event "Event buy_candy8" is the Topic field.
  • the smart contract under the premise of protecting user privacy, by identifying the event functions contained in the smart contract, it is possible to determine the exposed log fields that can be stored in plain text according to the differentiated requirements of different types of event functions for privacy protection , And further according to the satisfaction of the preset conditions by the exposure log field, the corresponding differentiated requirements are reflected in the storage process, and it has high flexibility.
  • the exposure log fields that meet the preset conditions can be stored in plaintext, and the exposure log fields that do not meet the preset conditions or other receipt content can be stored It must be stored in ciphertext.
  • the content of the preset condition may include at least one of the following: the corresponding log field contains the preset content, the value of the corresponding log field belongs to the preset numerical interval, and so on.
  • the preset content may include: one or more specified keywords, for example, the keyword may include predefined state variables, predefined intermediate variables, etc., so that when a certain exposed log field contains a state variable or intermediate as a keyword Variable, it can be determined that the exposure log field meets the preset conditions.
  • the keyword may include predefined state variables, predefined intermediate variables, etc., so that when a certain exposed log field contains a state variable or intermediate as a keyword Variable, it can be determined that the exposure log field meets the preset conditions.
  • the preset content may include: preset values.
  • the preset value can be a numeric value, which can be compared with the value of a state variable, etc., to determine whether the value of the state variable meets expectations; for another example, the preset value can be composed of numeric values, letters, special symbols, etc.
  • a character string which can be compared with the account address of the transaction initiator, the account address of the transaction target, the log subject, etc. to identify a specific transaction initiator, a specific transaction target, or a specific log subject, etc.
  • the user can store the To field in plain text when the user initiates a transaction against the account address and the exposure log field corresponding to the transaction type includes the To field. , And when a transaction is initiated against another account address, the To field is not allowed to be stored in plain text to avoid leaking privacy.
  • the preset value range can indicate the privacy protection requirements of the relevant receipt fields.
  • the preset value range can be a value range with a smaller value and a lower privacy protection requirement, so that even if the relevant receipt field is disclosed, it will not cause Serious user privacy leakage, but it can be used to automatically trigger related operations such as DAPP client, so as to achieve a certain balance between privacy protection and convenience. Therefore, when the value of the exposure log field is within the preset numerical range, the exposure log field can be stored in plain text.
  • the preset conditions may include general conditions corresponding to all log fields, that is, in the log corresponding to the special event function in the receipt data, all log fields contained in the log have a unified preset condition, so that the All exposure log fields contained in the log need to be compared with this unified preset condition.
  • the preset condition is "contains preset keywords”
  • all the exposure log fields in the log corresponding to the special event function can be compared with the keywords contained in the preset condition to determine that the keyword is included
  • the exposure log field of is used as the exposure log field that meets the above preset conditions.
  • the preset condition may include a dedicated condition corresponding to each log field, that is, in the log corresponding to the special event function in the receipt data, each log field contained in the log has a corresponding preset condition. , So that each exposure log field contained in the log is used for comparison with the corresponding preset conditions.
  • the preset conditions corresponding to different log fields are independent of each other, but may be the same or different.
  • the preset condition corresponding to the From field and the To field may be "whether the preset content is included", and the preset content may be a preset account address, indicating a transaction initiated by or directed to the account address.
  • the preset condition corresponding to the Topic field can be "whether it belongs to the preset value range", and the value of the state variable referenced by the related event can be recorded in the Topic field.
  • it can include a value representing "transfer amount” State variable, indicating that when the transfer amount is in the preset value range (usually the small value range corresponding to a smaller amount), the transfer amount is allowed to be stored in plain text (it can be in plain text when the Topic field is an exposure log field) storage).
  • the preset conditions may be located in the transaction, so that the preset conditions adopted by different exchanges may be different to meet the differences in demand faced by different exchanges; of course, different transactions may also use the same preset conditions.
  • the difference in the preset conditions may be expressed as a difference in at least one dimension in the content of the preset conditions, the receipt fields to which the preset conditions apply, and the processing logic for determining whether the exposure log field meets the preset conditions.
  • the preset condition may be located in the smart contract called by the transaction, or the preset condition may be located in another smart contract called by the smart contract called by the transaction, so that the transaction can be selected by selecting the called smart contract to Determine whether to use the corresponding preset conditions.
  • the smart contract can be pre-created by the transaction initiator or any other user; of course, if the smart contract has a corresponding calling condition, then the above-mentioned transaction can call the smart contract only when the calling condition is met.
  • the calling condition may include : The transaction initiator belongs to the preset whitelist, the transaction initiator does not belong to the preset blacklist or other conditions.
  • the preset condition may be located in the system contract or chain code, so that the preset condition is a global condition applicable to all transactions on the blockchain, and is different from the foregoing transaction or the preset contained in the smart contract.
  • Set conditions so that even if the smart contract called by the transaction or transaction does not contain preset conditions, the storage of log fields can be determined based on the preset conditions defined in the system contract or chain code, and combined with the user type of the transaction initiator the way.
  • the two can contain preset conditions of different dimensions, such as preset conditions.
  • the applicable log fields are different; or, when there is a conflict between the preset conditions contained in the two, the preset conditions contained in the transaction or smart contract may be used by default, or the preset conditions contained in the chain code or system contract may be preferred.
  • Set conditions which depend on the predefined selection logic.
  • the computing device By running the program code of the blockchain (hereinafter referred to as the chain code) on the computing device (physical machine or virtual machine), the computing device can be configured as a blockchain node in the blockchain network, such as the first Blockchain nodes, etc.
  • the first blockchain node runs the above chain code to realize the corresponding functional logic. Therefore, when creating a blockchain network, the above-mentioned receipt data storage logic related to event functions and preset conditions can be written into the chain code, so that each blockchain node can implement the receipt data storage logic .
  • Receipt data storage logic related to event functions and preset conditions may include: recognition logic for special event functions, confirmation logic for exposed log fields, determination logic for preset conditions, processing logic for exposed log fields, and the like.
  • the recognition logic of the special event function is used to instruct the first blockchain node to identify the special event function contained in the smart contract.
  • the system contract can record a list of predefined special event functions, or the system contract can record the processing logic for identifying special event functions based on type identifiers. For details, please refer to the relevant description of identifying special event functions above, which will not be repeated here.
  • the confirmation logic for the exposure log field is used to instruct the first blockchain node: to determine the corresponding exposure log field according to the special event function. For example: Determine the corresponding exposure log field according to the exposure identifier or encryption identifier contained in the special event function; or, according to the mapping relationship between the special event function and the exposure log field recorded in the chain code or system contract or block , And determine the corresponding exposure log field in combination with the special event function included in the currently initiated exchange. For details, please refer to the relevant description of the exposed log field corresponding to the known special event function above, which will not be repeated here.
  • the logic for determining the preset conditions is used to instruct the first blockchain node to obtain preset conditions applicable to the exposure log field. For example: obtain general conditions applicable to all receipt fields, or obtain special conditions applicable to exposure log fields, etc. For details, please refer to the relevant description of the preset conditions above, which will not be repeated here.
  • the processing logic for the exposed log field is used to instruct the first blockchain node: to store the receipt content corresponding to the exposed log field in the receipt data.
  • the receipt content in the log corresponding to the exposure log field and meeting the preset conditions can be stored in plain text, and the log corresponding to the exposure log field and not satisfying
  • the receipt content of the preset conditions and the receipt content corresponding to the non-exposed fields are stored in cipher text, and other receipt content in the receipt data (such as the receipt content corresponding to the ordinary event function) is stored in cipher text.
  • other receipt content in the receipt data (such as the receipt content corresponding to the ordinary event function) is stored in cipher text.
  • chain code is used to realize the basic functions of the blockchain network, and the function expansion during operation can be achieved through the system Realized by way of contract.
  • the system contract includes code in the form of bytecode, for example, the first blockchain node can run the system contract code (for example, according to the unique corresponding address "0x53a98" to read the system The code in the contract) to realize the functional supplement of the chain code.
  • the first blockchain node can read the code of the system contract, which defines the receipt data storage logic related to transaction types and event functions; then, the first blockchain node can execute the system contract Based on the receipt data storage logic related to the event function and preset conditions, the exposed log fields that meet the preset conditions in the log corresponding to the special event function are stored in plain text, and the rest of the receipt data is stored in cipher text. storage.
  • the system contract read by the first blockchain node may include a preset system contract configured in the genesis block of the blockchain network; and, the administrator in the blockchain network (ie, the above-mentioned management user) may have The update authority of the system contract, so as to update the preset system contract such as the above, the system contract read by the first blockchain node may also include the corresponding updated system contract.
  • the updated system contract can be obtained by the administrator after one update of the preset system contract; or, the updated system contract can be obtained by the administrator after multiple iterations of the preset system contract, such as the preset system contract Update the system contract 1, update the system contract 1 to obtain the system contract 2, update the system contract 2 to obtain the system contract 3.
  • the system contract 1, the system contract 2, and the system contract 3 can all be regarded as the updated system contract, but the first Blockchain nodes usually follow the latest version of the system contract. For example, the first blockchain node will follow the code in system contract 3 instead of the code in system contract 1 or system contract 2.
  • the administrator can also publish system contracts in subsequent blocks and update the published system contracts.
  • system contracts in subsequent blocks and update the published system contracts.
  • a certain degree of restrictions should be imposed on the issuance and update of system contracts through methods such as authority management to ensure that the functional logic of the blockchain network can operate normally and avoid unnecessary losses to any users.
  • the first blockchain node For the receipt content that needs to be stored in cipher text in the receipt data, the first blockchain node encrypts the receipt content with a key.
  • the encryption may be symmetric encryption or asymmetric encryption. If the first blockchain node uses symmetric encryption, that is, the symmetric key of the symmetric encryption algorithm is used to encrypt the content of the receipt, the client (or other object holding the key) can use the symmetric key pair of the symmetric encryption algorithm The encrypted receipt content is decrypted.
  • the symmetric key may be provided to the first blockchain node in advance by the client. Then, since only the client (actually the user corresponding to the logged-in account on the client) and the first blockchain node have the symmetric key, only the client can decrypt the corresponding encrypted receipt content, avoiding Irrelevant users and even criminals decrypt the encrypted receipt content.
  • the client when the client initiates a transaction to the first blockchain node, the client can use the initial key of the symmetric encryption algorithm to encrypt the transaction content to obtain the transaction; accordingly, the first blockchain node can obtain
  • the initial key is used to directly or indirectly encrypt the content of the receipt.
  • the initial key can be negotiated in advance by the client and the first blockchain node, or sent by the key management server to the client and the first blockchain node, or sent by the client to the first blockchain node.
  • the client can encrypt the initial key with the public key of the asymmetric encryption algorithm, and then send the encrypted initial key to the first block
  • the chain node, and the first blockchain node decrypts the encrypted initial key through the private key of the asymmetric encryption algorithm to obtain the initial key, which is the digital envelope encryption described above, which will not be repeated here.
  • the first blockchain node may use the aforementioned initial key to encrypt the content of the receipt.
  • Different transactions can use the same initial key, so that all transactions submitted by the same user are encrypted with this initial key, or different transactions can use different initial keys.
  • the client can randomly generate an initial key for each transaction. Key to improve security.
  • the first blockchain node may generate a derived key according to the initial key and the impact factor, and encrypt the content of the receipt through the derived key.
  • the derived key can increase the degree of randomness, thereby increasing the difficulty of being compromised and helping to optimize the security protection of data.
  • the impact factor can be related to the transaction; for example, the impact factor can include the specified bits of the transaction hash value.
  • the first blockchain node can associate the initial key with the first 16 bits (or the first 32 bits and the last 16 bits) of the transaction hash value. Bits, last 32 bits, or other bits) are spliced, and the spliced string is hashed to generate a derived key.
  • the first blockchain node may also use an asymmetric encryption method, that is, use the public key of the asymmetric encryption algorithm to encrypt the content of the receipt, and accordingly, the client may use the private key of the asymmetric encryption algorithm.
  • the key decrypts the encrypted receipt content.
  • the key of an asymmetric encryption algorithm for example, can be that the client generates a pair of public and private keys, and sends the public key to the first blockchain node in advance, so that the first blockchain node can use the receipt content Public key encryption.
  • the first blockchain node realizes the function by running the code used to realize the function. Therefore, for the functions that need to be implemented in the TEE, the relevant code also needs to be executed. For the code executed in the TEE, it needs to comply with the relevant specifications and requirements of the TEE; accordingly, for the code used to implement a certain function in the related technology, the code needs to be rewritten in combination with the specifications and requirements of the TEE. Large amount of development, and easy to produce loopholes (bugs) in the process of rewriting, affecting the reliability and stability of function implementation.
  • the first blockchain node can execute the storage function code outside the TEE to store the receipt data generated in the TEE (including the receipt content in plain text that needs to be stored in plain text, and the receipt content in cipher text that needs to be stored in cipher text.
  • TEE Is stored in an external storage space outside the TEE, so that the storage function code can be the code used to implement the storage function in the related technology, and does not need to be rewritten in conjunction with the specifications and requirements of the TEE to achieve safe and reliable receipt data
  • the storage of TEE can not only reduce the amount of related code development without affecting security and reliability, but also reduce TCB (Trusted Computing Base) by reducing the related code of TEE, making TEE technology and regional In the process of combining block chain technology, the additional security risks caused are in a controllable range.
  • TCB Trusted Computing Base
  • the first blockchain node may execute the write cache function code in the TEE to store the above-mentioned receipt data in the write cache in the TEE.
  • the write cache may correspond to the one shown in FIG. 1 "Cache".
  • the first blockchain node outputs the data in the write cache from the trusted execution environment to be stored in the external storage space.
  • the write cache function code can be stored in the TEE in plain text, and the cache function code in the plain text can be directly executed in the TEE; or, the write cache function code can be stored outside the TEE in cipher text, such as the above External storage space (such as the "package + storage” shown in Figure 4, where "package” means that the first blockchain node packages the transaction into blocks outside of the trusted execution environment), the cipher text form
  • the write cache function code is read into the TEE, decrypted into the plaintext code in the TEE, and the plaintext code is executed.
  • Write cache refers to a "buffer" mechanism provided to avoid “impact” to the external storage space when data is written to the external storage space.
  • the above-mentioned write cache can be implemented by using buffer; of course, the write cache can also be implemented by using cache, which is not limited in this specification.
  • the write cache mechanism can be used to write the data in the cache to the external storage space in batches, thereby reducing the gap between the TEE and the external storage space. The number of interactions increases the efficiency of data storage.
  • TEE may need to retrieve the generated data.
  • the data to be called happens to be in the write cache, the data can be read directly from the write cache.
  • the interaction between the external storage space eliminates the decryption process of the data read from the external storage space, thereby improving the data processing efficiency in the TEE.
  • the write cache can also be established outside the TEE.
  • the first blockchain node can execute the write cache function code outside the TEE, so as to store the above receipt data in the write cache outside the TEE, and further write The data in the cache is stored in an external storage space.
  • the receiving unit 61 receives the encrypted transaction of calling the smart contract
  • a decryption unit 62 decrypting the transaction in a trusted execution environment to obtain the smart contract, the smart contract including a special event function;
  • the execution unit 63 executes the smart contract in the trusted execution environment to obtain receipt data, where the receipt data includes a log corresponding to the special event function;
  • the storage unit 64 stores the receipt data so that at least one log field that meets a preset condition in the log corresponding to the special event function is stored in plain text, and the rest of the receipt data is stored in cipher text.
  • the event function in the smart contract includes a type identifier, and the type identifier is used to mark the event function as a special event function.
  • the event function included in the smart contract is in the special function list recorded on the blockchain, the event function included in the smart contract is determined to be a special event function.
  • the at least one log field includes: an exposure log field corresponding to the special event function.
  • the special event function includes the exposed log field indicated by an exposure identifier; or, the special event function includes an encrypted log field indicated by an encrypted identifier, and the exposed log field is another log Field.
  • mapping relationship between a predefined special event function and an exposed log field, or a mapping relationship between a predefined special event function and an encrypted log field is recorded in the blockchain; the mapping relationship is used for Determine the exposure log field corresponding to the special event function.
  • the preset condition includes at least one of the following: the corresponding log field contains preset content, and the value of the corresponding log field belongs to a preset numerical interval.
  • the preset conditions include general conditions corresponding to all log fields; or,
  • the preset condition includes a dedicated condition corresponding to each log field.
  • the preset condition is in the transaction; or,
  • the preset condition is located in the smart contract called by the transaction, or in another smart contract called by the smart contract called by the transaction; or,
  • the preset conditions are located in the system contract or chain code.
  • the storage unit 64 is specifically used for:
  • the code of the system contract is executed to store at least one log field that meets a preset condition in the log corresponding to the special event function in plain text, and the rest of the receipt data is stored in cipher text.
  • the system contract includes: a preset system contract recorded in the genesis block, or an updated system contract corresponding to the preset system contract.
  • the storage unit 64 is specifically used for:
  • the storage function code is executed outside the trusted execution environment to store the receipt data in an external storage space outside the trusted execution environment.
  • the key used by the first blockchain node to encrypt the receipt data includes: a key of a symmetric encryption algorithm or a key of an asymmetric encryption algorithm.
  • the key of the symmetric encryption algorithm includes an initial key provided by the client; or, the key of the symmetric encryption algorithm includes a derived key generated by the initial key and an influence factor.
  • the transaction is encrypted by the initial key, and the initial key is encrypted by the public key of an asymmetric encryption algorithm; the decryption unit 62 is specifically configured to:
  • the initial key is generated by the client; or, the initial key is sent to the client by the key management server.
  • the impact factor is related to the transaction.
  • the impact factor includes: a designated bit of the hash value of the transaction.
  • a programmable logic device Programmable Logic Device, PLD
  • FPGA Field Programmable Gate Array
  • HDL Hardware Description Language
  • ABEL Advanced Boolean Expression Language
  • AHDL Altera Hardware Description Language
  • HDCal JHDL
  • Lava Lava
  • Lola MyHDL
  • PALASM RHDL
  • Verilog Verilog
  • the controller can be implemented in any suitable manner.
  • the controller can take the form of, for example, a microprocessor or a processor and a computer-readable medium storing computer-readable program codes (such as software or firmware) executable by the (micro)processor. , Logic gates, switches, application specific integrated circuits (ASICs), programmable logic controllers and embedded microcontrollers. Examples of controllers include but are not limited to the following microcontrollers: ARC625D, Atmel AT91SAM, Microchip PIC18F26K20 and Silicon Labs C8051F320, the memory controller can also be implemented as part of the memory control logic.
  • controller in addition to implementing the controller in a purely computer-readable program code manner, it is entirely possible to program the method steps to make the controller use logic gates, switches, application specific integrated circuits, programmable logic controllers and embedded The same function can be realized in the form of a microcontroller, etc. Therefore, such a controller can be regarded as a hardware component, and the devices included in it for implementing various functions can also be regarded as a structure within the hardware component. Or even, the device for realizing various functions can be regarded as both a software module for realizing the method and a structure within a hardware component.
  • a typical implementation device is a computer.
  • the computer may be, for example, a personal computer, a laptop computer, a cell phone, a camera phone, a smart phone, a personal digital assistant, a media player, a navigation device, an email device, a game console, a tablet computer, a wearable device, or Any combination of these devices.
  • the embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes.
  • a computer-usable storage media including but not limited to disk storage, CD-ROM, optical storage, etc.
  • program modules include routines, programs, objects, components, data structures, etc. that perform specific tasks or implement specific abstract data types.
  • This specification can also be practiced in distributed computing environments, in which tasks are performed by remote processing devices connected through a communication network.
  • program modules can be located in local and remote computer storage media including storage devices.
  • These computer program instructions can also be stored in a computer-readable memory that can guide a computer or other programmable data processing equipment to work in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture including the instruction device.
  • the device implements the functions specified in one process or multiple processes in the flowchart and/or one block or multiple blocks in the block diagram.
  • These computer program instructions can also be loaded on a computer or other programmable data processing equipment, so that a series of operation steps are executed on the computer or other programmable equipment to produce computer-implemented processing, so as to execute on the computer or other programmable equipment.
  • the instructions provide steps for implementing functions specified in a flow or multiple flows in the flowchart and/or a block or multiple blocks in the block diagram.
  • the computer includes one or more processors (CPU), input/output interfaces, network interfaces, and memory.
  • the memory may include non-permanent memory in computer readable media, random access memory (RAM) and/or non-volatile memory, such as read-only memory (ROM) or flash memory (flash RAM). Memory is an example of computer readable media.
  • RAM random access memory
  • ROM read-only memory
  • flash RAM flash memory
  • Computer-readable media include permanent and non-permanent, removable and non-removable media, and information storage can be realized by any method or technology.
  • the information can be computer-readable instructions, data structures, program modules, or other data.
  • Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, CD-ROM, digital versatile disc (DVD) or other optical storage, Magnetic cassettes, magnetic disk storage, quantum memory, graphene-based storage media or other magnetic storage devices or any other non-transmission media can be used to store information that can be accessed by computing devices. According to the definition in this article, computer-readable media does not include transitory media, such as modulated data signals and carrier waves.
  • first, second, third, etc. may be used in one or more embodiments of this specification to describe various information, the information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other.
  • first information may also be referred to as second information, and similarly, the second information may also be referred to as first information.
  • word “if” as used herein can be interpreted as "when” or “when” or "in response to determination”.

Abstract

一种结合事件函数类型和判断条件的收据存储方法和节点，该方法包括：第一区块链节点接收经过加密的调用智能合约的交易（302）；第一区块链节点在可信执行环境中解密所述交易以获得所述智能合约，所述智能合约包含特殊事件函数（304）；第一区块链节点在所述可信执行环境中执行所述智能合约，得到收据数据，所述收据数据包含对应于所述特殊事件函数的日志（306）；第一区块链节点存储所述收据数据，使对应于所述特殊事件函数的日志中满足预设条件的至少一个日志字段以明文形式存储、所述收据数据的其余内容以密文形式存储（308）。

Description

结合事件函数类型和判断条件的收据存储方法和节点 技术领域
本说明书一个或多个实施例涉及区块链技术领域，尤其涉及一种结合事件函数类型和判断条件的收据存储方法和节点。
背景技术
区块链技术构建在传输网络(例如点对点网络)之上。传输网络中的网络节点利用链式数据结构来验证与存储数据，并采用分布式节点共识算法来生成和更新数据。
目前企业级的区块链平台技术上最大的两个挑战就是隐私和性能，往往这两个挑战很难同时解决。大多解决方案都是通过损失性能换取隐私，或者不大考虑隐私去追求性能。常见的解决隐私问题的加密技术，如同态加密(Homomorphic encryption)和零知识证明(Zero-knowledge proof)等复杂度高，通用性差，而且还可能带来严重的性能损失。
可信执行环境(Trusted Execution Environment,TEE)是另一种解决隐私问题的方式。TEE可以起到硬件中的黑箱作用，在TEE中执行的代码和数据操作系统层都无法偷窥，只有代码中预先定义的接口才能对其进行操作。在效率方面，由于TEE的黑箱性质，在TEE中进行运算的是明文数据，而不是同态加密中的复杂密码学运算，计算过程效率没有损失，因此与TEE相结合可以在性能损失较小的前提下很大程度上提升区块链的安全性和隐私性。目前工业界十分关注TEE的方案，几乎所有主流的芯片和软件联盟都有自己的TEE解决方案，包括软件方面的TPM(Trusted Platform Module，可信赖平台模块)以及硬件方面的Intel SGX(Software Guard Extensions,软件保护扩展)、ARM Trustzone(信任区)和AMD PSP(Platform Security Processor，平台安全处理器)。
发明内容
有鉴于此，本说明书一个或多个实施例提供一种结合事件函数类型和判断条件的收据存储方法和节点。
为实现上述目的，本说明书一个或多个实施例提供技术方案如下：
根据本说明书一个或多个实施例的第一方面，提出了一种结合事件函数类型和判断条件的收据存储方法，包括：
第一区块链节点接收经过加密的调用智能合约的交易；
第一区块链节点在可信执行环境中解密所述交易以获得所述智能合约，所述智能合约包含特殊事件函数；
第一区块链节点在所述可信执行环境中执行所述智能合约，得到收据数据，所述收据数据包含对应于所述特殊事件函数的日志；
第一区块链节点存储所述收据数据，使对应于所述特殊事件函数的日志中满足预设条件的至少一个日志字段以明文形式存储、所述收据数据的其余内容以密文形式存储。
根据本说明书一个或多个实施例的第二方面，提出了一种结合事件函数类型和判断条件的收据存储节点，包括：
接收单元，接收经过加密的调用智能合约的交易；
解密单元，在可信执行环境中解密所述交易以获得所述智能合约，所述智能合约包含特殊事件函数；
执行单元，在所述可信执行环境中执行所述智能合约，得到收据数据，所述收据数据包含对应于所述特殊事件函数的日志；
存储单元，存储所述收据数据，使对应于所述特殊事件函数的日志中满足预设条件的至少一个日志字段以明文形式存储、所述收据数据的其余内容以密文形式存储。
根据本说明书一个或多个实施例的第三方面，提出了一种电子设备，包括：
处理器；
用于存储处理器可执行指令的存储器；
其中，所述处理器通过运行所述可执行指令以实现如第一方面所述的方法。
根据本说明书一个或多个实施例的第四方面，提出了一种计算机可读存储介质，其上存储有计算机指令，该指令被处理器执行时实现如第一方面所述方法的步骤。
附图说明
图1是一示例性实施例提供的一种创建智能合约的示意图。
图2是一示例性实施例提供的一种调用智能合约的示意图。
图3是一示例性实施例提供的一种结合事件函数类型和判断条件的收据存储方法的 流程图。
图4是一示例性实施例提供的一种在区块链节点上实现隐私保护的示意图。
图5是一示例性实施例提供的一种通过系统合约和链代码实现区块链网络的功能逻辑的示意图。
图6是一示例性实施例提供的一种结合事件函数类型和判断条件的收据存储节点的框图。
具体实施方式
这里将详细地对示例性实施例进行说明，其示例表示在附图中。下面的描述涉及附图时，除非另有表示，不同附图中的相同数字表示相同或相似的要素。以下示例性实施例中所描述的实施方式并不代表与本说明书一个或多个实施例相一致的所有实施方式。相反，它们仅是与如所附权利要求书中所详述的、本说明书一个或多个实施例的一些方面相一致的装置和方法的例子。
需要说明的是：在其他实施例中并不一定按照本说明书示出和描述的顺序来执行相应方法的步骤。在一些其他实施例中，其方法所包括的步骤可以比本说明书所描述的更多或更少。此外，本说明书中所描述的单个步骤，在其他实施例中可能被分解为多个步骤进行描述；而本说明书中所描述的多个步骤，在其他实施例中也可能被合并为单个步骤进行描述。
区块链一般被划分为三种类型：公有链(Public Blockchain)，私有链(Private Blockchain)和联盟链(Consortium Blockchain)。此外，还有多种类型的结合，比如私有链+联盟链、联盟链+公有链等不同组合形式。其中去中心化程度最高的是公有链。公有链以比特币、以太坊为代表，加入公有链的参与者可以读取链上的数据记录、参与交易以及竞争新区块的记账权等。而且，各参与者(即节点)可自由加入以及退出网络，并进行相关操作。私有链则相反，该网络的写入权限由某个组织或者机构控制，数据读取权限受组织规定。简单来说，私有链可以为一个弱中心化系统，参与节点具有严格限制且少。这种类型的区块链更适合于特定机构内部使用。联盟链则是介于公有链以及私有链之间的区块链，可实现“部分去中心化”。联盟链中各个节点通常有与之相对应的实体机构或者组织；参与者通过授权加入网络并组成利益相关联盟，共同维护区块链运行。
不论是公有链、私有链还是联盟链，都可能提供智能合约的功能。区块链上的智能合约是在区块链系统上可以被交易触发执行的合约。智能合约可以通过代码的形式定义。
以以太坊为例，支持用户在以太坊网络中创建并调用一些复杂的逻辑，这是以太坊区别于比特币区块链技术的最大挑战。以太坊作为一个可编程区块链的核心是以太坊虚拟机(EVM)，每个以太坊节点都可以运行EVM。EVM是一个图灵完备的虚拟机，这意味着可以通过它实现各种复杂的逻辑。用户在以太坊中发布和调用智能合约就是在EVM上运行的。实际上，虚拟机直接运行的是虚拟机代码(虚拟机字节码，下简称“字节码”)。部署在区块链上的智能合约可以是字节码的形式。
例如图1所示，Bob将一个包含创建智能合约信息的交易发送到以太坊网络后，节点1的EVM可以执行这个交易并生成对应的合约实例。图中1中的“0x6f8ae93…”代表了这个合约的地址，交易的data字段保存的可以是字节码，交易的to字段为空。节点间通过共识机制达成一致后，这个合约成功创建，并且可以在后续过程中被调用。合约创建后，区块链上出现一个与该智能合约对应的合约账户，并拥有一个特定的地址，合约代码将保存在该合约账户中。智能合约的行为由合约代码控制。换句话说，智能合约使得区块链上产生包含合约代码和账户存储(Storage)的虚拟账户。
如图2所示，仍以以太坊为例，Bob将一个用于调用智能合约的交易发送到以太坊网络后，某一节点的EVM可以执行这个交易并生成对应的合约实例。图中2中交易的from字段是交易发起方(即Bob)的账户的地址，to字段中的“0x6f8ae93…”代表了被调用的智能合约的地址，value字段在以太坊中是以太币的值，交易的data字段保存的调用智能合约的方法和参数。智能合约以规定的方式在区块链网络中每个节点独立的执行，所有执行记录和数据都保存在区块链上，所以当交易完成后，区块链上就保存了无法篡改、不会丢失的交易凭证。
区块链网络中的节点在执行Bob发起的交易后，会生成相应的收据(receipt)数据，以用于记录该交易相关的收据信息。以以太坊为例，节点执行交易所得的收据数据可以包括如下内容：
Result字段，表示交易的执行结果；
Gas used字段，表示交易消耗的gas值；
Logs字段，表示交易产生的日志，日志可以进一步包括From字段、To字段、Topic字段和Log data字段等，其中From字段表示调用的发起方的账户地址、To字段表示被 调用对象(如智能合约)的账户地址、Topic字段表示日志的主题、Log data字段表示日志数据；
Output字段，表示交易的输出。
其中，日志是以太坊中提供的一项功能。在智能合约的代码的运行过程中，可以记录代码所含的各个事件所产生的日志。日志允许记录事件的细节，比如上述的From字段、To字段可以表明交易涉及的双方账户，Topic字段可以包含事件所引用的状态变量等在代码执行后的取值等。因此，日志除了可以作为交易在区块链上执行后的相关证据，还可以用于驱动相关操作。例如，可以使用JavaScript的回调函数监听事件，当事件触发时可以产生相应的日志，因而通过检索日志内容，可以在检索到预设日志内容时驱动DAPP(Decentralized Application，分布式应用)客户端执行相关处理操作等。
在相关技术中，TEE内生成的收据数据的全部内容均被当作需要隐私保护的数据而加密存储在区块链上。所述区块链，是存储在节点的数据库中特定逻辑组织而成的数据集合。所述数据库，如后所述，其物理载体可以存储介质，例如持久性存储介质。当收据数据所含的日志被加密存储时，针对日志的检索操作可能无法正常实施，从而影响到上述DAPP客户端对相关处理操作的执行。
以下结合图3所示说明本申请一结合事件函数类型和判断条件的收据存储方法的实施例的实现过程：
步骤302，第一区块链节点接收经过加密的调用智能合约的交易。
在一实施例中，用户可以直接在第一区块链节点上生成交易；或者，用户可以在客户端上生成交易，并通过客户端将该交易发送至第一区块链节点；或者，客户端可以将上述交易发送至第二区块链节点，并由第二区块链节点将该交易发送至第一区块链节点。
在一实施例中，当交易用于调用智能合约时，交易内容可以包括被调用的智能合约的账户地址、需要传入的方法和参数等。
步骤304，第一区块链节点在可信执行环境中解密所述交易以获得所述智能合约，所述智能合约包含特殊事件函数。
在一实施例中，智能合约可以包含一个或多个事件，每一事件用于实现预定义的相关处理逻辑。智能合约所含的每一事件被调用执行后，均会生成对应的Logs字段，比如当智能合约包含事件1和事件2时，事件1可以生成对应的Logs字段、事件2可以生成对应的Logs字段，使得该智能合约对应的收据数据同时包含多个Logs字段。
在一实施例中，智能合约所含的事件可以分为特殊事件函数和普通事件函数，其中：普通事件函数所产生的日志采用密文形式进行存储，以实现隐私保护；特殊事件函数所产生的日志则需要在满足隐私保护需求的前提下，将至少一部分日志字段(例如下文中的暴露日志字段)以明文形式进行存储，从而可以针对该部分日志字段的内容实施检索，以驱动相关操作的实施。
在一实施例中，特殊事件函数可以为区块链网络中预定义的全局事件函数。比如在区块链网络的链代码或系统合约中，可以记录属于“特殊事件函数”的的事件函数，譬如可以记录在特殊事件函数列表中；相应地，通过将智能合约中包含的事件函数与上述的特殊事件函数列表进行对比，可以确定智能合约包含的事件函数是否为上述的特殊事件函数。
在一实施例中，特殊事件函数可以为智能合约中自定义的任意函数，并通过在智能合约中添加针对事件函数的类型标识符，可以将该事件函数标记为特殊事件函数。以Solidity语言为例，智能合约包含的事件函数的代码示例如下：
Event buy_candy1 expose(who,candy_num)；
Event buy_candy2(who,candy_num)；
在上述代码示例中，智能合约定义了2个事件：事件buy_candy1和事件buy_candy2。通过在事件buy_candy1中添加类型标识符“expose”，可以将该事件buy_candy1标记为上述的特殊事件函数；相应的，由于事件buy_candy2中并未包含类型标识符“expose”，因而事件buy_candy2为普通事件函数、而非上述的特殊事件函数。
以太坊支持的高级语言很多，如Solidity、Serpent、LLL语言等，均可以包含上述的类型标识符。通过编译器可以将高级语言编写的智能合约编译为相应的字节码，第一区块链节点最终在EVM虚拟机中执行字节码形式的智能合约。那么，上述的类型标识符在高级语言和字节码形式的智能合约代码中可以相同，或者高级语言的智能合约代码中为第一类型标识符、字节码形式的智能合约代码中为第二类型标识符，第一类型标识符与第二类型标识符之间可以相互对应。
在一实施例中，通过对交易内容进行加密，可使上述经过加密的交易处于隐私保护的状态，避免交易内容发生暴露。譬如，交易内容中可能包含交易发起方的账户地址、交易目标的账户地址等信息，通过加密处理可以确保这些交易内容均无法被直接读取。
在一实施例中，上述交易可以通过对称加密算法的方式进行加密，也可以采用非对 称算法的方式进行加密。对称加密采用的加密算法，例如是DES算法，3DES算法，TDEA算法，Blowfish算法，RC5算法，IDEA算法等。非对称加密算法，例如是RSA、Elgamal、背包算法、Rabin、D-H、ECC(椭圆曲线加密算法)等。
在一实施例中，上述交易可以通过对称加密算法结合非对称加密算法的方式进行加密。以客户端将上述交易提交至第一区块链节点为例，客户端可以采用对称加密算法加密交易内容，即采用对称加密算法的密钥加密交易内容，并用非对称加密算法加密对称加密算法中采用的密钥，譬如采用非对称加密算法的公钥加密对称加密算法中采用的密钥。这样，第一区块链节点接收到加密的交易后，可以先采用非对称加密算法的私钥进行解密，得到对称加密算法的密钥，进而用对称加密算法的密钥解密得到交易内容。
当交易用于调用智能合约时，可以是多重嵌套结构的调用。例如，交易直接调用智能合约1，而该智能合约1的代码调用了智能合约2，且智能合约2中的代码指向了智能合约3的合约地址，使得交易实际上间接调用了智能合约3的代码，而智能合约3中包括某一事件函数。这样，相当于智能合约1中包含了该事件函数。具体实现过程与上述过程类似，在此不再赘述。
步骤306，第一区块链节点在所述可信执行环境中执行所述智能合约，得到收据数据，所述收据数据包含对应于所述特殊事件函数的日志。
如前所述，第一区块链节点在执行智能合约的代码时，针对代码所含的每一事件函数，将分别生成对应的Logs字段，即分别生成对应于每一事件函数的日志。通过确定出特殊事件函数，可以进一步确定出特殊事件函数对应的日志，并在特殊事件函数对应的至少一部分日志字段满足预设条件的情况下，允许该至少一部分日志字段采用明文形式进行存储。
在一实施例中，比如在以太坊中，第一区块链节点接收到客户端发来的调用智能合约的交易后，可以检查交易是否有效、格式是否正确，验证交易的签名是否合法等。
一般来说，以太坊中的节点一般也是争夺记账权的节点，因此，第一区块链节点作为争夺记账权的节点可以在本地执行所述交易。如果争夺记账权的节点中的一个在本轮争夺记账权的过程中胜出，则成为记账节点。第一区块链节点如果在本轮争夺记账权的过程中胜出，就成为记账节点；当然，如果第一区块链节点如果在本轮争夺记账权的过程中没有胜出，则不是记账节点，而其它节点可能成为记账节点。
智能合约类似于面向对象编程中的类，执行的结果生成对应该智能合约的合约实例， 类似于生成类对应的对象。执行交易中用于创建智能合约的代码的过程，会创建合约账户，并在账户空间中部署合约。以太坊中，智能合约账户的地址是由发送者的地址(如图1-2中的“0xf5e…”)和交易随机数(nonce)作为输入，通过加密算法生成的，比如图1-2中的合约地址“0x6f8ae93…”即由发送者的地址“0xf5e…”和交易中的nonce经加密算法生成。
一般的，采用工作量证明(Proof of Work,POW)以及股权证明(Proof of Stake，POS)、委任权益证明(Delegated Proof of Stake，DPOS)等共识算法的支持智能合约的区块链网络中，争夺记账权的节点都可以在接收到包含创建智能合约的交易后执行所述交易。争夺记账权的节点中可能其中一个在本轮争夺记账权的过程中胜出，成为记账节点。记账节点可以将该包含智能合约的交易与其它交易一起打包并生成新的区块，并将生成的新的区块发送至其它节点进行共识。
对于采用实用拜占庭容错(Practical Byzantine Fault Tolerance，PBFT)等机制的支持智能合约的区块链网络中，具有记账权的节点在本轮记账前已经商定好。因此，第一区块链节点接收到上述交易后，如果自身不是本轮的记账节点，则可以将该交易发送至记账节点。对于本轮的记账节点(可以是第一区块链节点)，在将该交易打包并生成新区块的过程中或者之前，或在将该交易与其它交易一起打包并生成新区块的过程中或者之前，可以执行该交易。所述记账节点将该交易打包(或还包括其它交易一起打包)并生成新的区块后，将生成的新的区块或者区块头发送至其它节点进行共识。
如上所述，采用POW机制的支持智能合约的区块链网络中，或者采用POS、DPOS、PBFT机制的支持智能合约的区块链网络中，本轮的记账节点都可以将该交易打包并生成新的区块，并将生成的新的区块后区块头发送至其它节点进行共识。如果其它节点接收到所述区块后经验证没有问题，可以将该新的区块追加到原有的区块链末尾，从而完成记账过程，达成共识；若交易用于创建智能合约，则完成了智能合约在区块链网络上的部署，若交易用于调用智能合约，则完成了智能合约的调用和执行。其它节点验证记账节点发来的新的区块或区块头的过程中，也可以执行所述区块中的交易。
所述执行过程，一般可以通过虚拟机执行。以以太坊为例，支持用户在以太坊网络中创建和/或调用一些复杂的逻辑，这是以太坊区别于比特币区块链技术的最大挑战。以太坊作为一个可编程区块链的核心是以太坊虚拟机(EVM，Ethereum Virtual Machine)，每个以太坊节点都可以运行EVM。EVM是一个图灵完备的虚拟机，这意味着可以通过它实现各种复杂的逻辑。用户在以太坊中发布和调用智能合约就是在EVM上运行的。
本实施例中，第一区块链节点可以在可信执行环境(Trusted Execution Environment，TEE)中执行解密的智能合约的代码。例如图4所示，第一区块链节点可以划分为常规执行环境(图中位于左侧)和TEE，客户端提交的交易(如上文所述，交易可以存在其他来源；此处以客户端提交的交易为例进行说明)首先进入常规执行环境中的“交易/查询接口”进行识别，不存在隐私处理需求的交易可以被留在常规执行环境中进行处理(这里可以根据交易发起方的用户类型、交易类型、交易所含的标识符等识别是否存在隐私处理需求)，而将存在隐私处理需求的交易传递至TEE中进行处理。TEE与常规执行环境相互隔离。交易在进入TEE之前处于加密状态，在可信执行环境内则被解密为明文的交易内容，从而在确保数据安全的前提下，使得该明文的交易内容能够在TEE中实现高效处理，并在TEE中生成明文的收据数据。
TEE是基于CPU硬件的安全扩展，且与外部完全隔离的可信执行环境。TEE最早是由Global Platform提出的概念，用于解决移动设备上资源的安全隔离，平行于操作系统为应用程序提供可信安全的执行环境。ARM的Trust Zone技术最早实现了真正商用的TEE技术。伴随着互联网的高速发展，安全的需求越来越高，不仅限于移动设备，云端设备，数据中心都对TEE提出了更多的需求。TEE的概念也得到了高速的发展和扩充。现在所说的TEE相比与最初提出的概念已经是更加广义的TEE。例如，服务器芯片厂商Intel，AMD等都先后推出了硬件辅助的TEE并丰富了TEE的概念和特性，在工业界得到了广泛的认可。现在提起的TEE通常更多指这类硬件辅助的TEE技术。不同于移动端，云端访问需要远程访问，终端用户对硬件平台不可见，因此使用TEE的第一步就是要确认TEE的真实可信。因此现在的TEE技术都引入了远程证明机制，由硬件厂商(主要是CPU厂商)背书并通过数字签名技术确保用户对TEE状态可验证。同时仅仅是安全的资源隔离也无法满足的安全需求，进一步的数据隐私保护也被提出。包括Intel SGX，AMD SEV在内的商用TEE也都提供了内存加密技术，将可信硬件限定在CPU内部，总线和内存的数据均是密文防止恶意用户进行窥探。例如，英特尔的软件保护扩展(SGX)等TEE技术隔离了代码执行、远程证明、安全配置、数据的安全存储以及用于执行代码的可信路径。在TEE中运行的应用程序受到安全保护，几乎不可能被第三方访问。
以Intel SGX技术为例，SGX提供了围圈(enclave，也称为飞地)，即内存中一个加密的可信执行区域，由CPU保护数据不被窃取。以第一区块链节点采用支持SGX的CPU为例，利用新增的处理器指令，在内存中可以分配一部分区域EPC(Enclave Page Cache，围圈页面缓存或飞地页面缓存)，通过CPU内的加密引擎MEE(Memory  Encryption Engine)对其中的数据进行加密。EPC中加密的内容只有进入CPU后才会被解密成明文。因此，在SGX中，用户可以不信任操作系统、VMM(Virtual Machine Monitor，虚拟机监控器)、甚至BIOS(Basic Input Output System，基本输入输出系统)，只需要信任CPU便能确保隐私数据不会泄漏。实际应用中，可以将隐私数据加密后以密文形式传递至围圈中，并通过远程证明将对应的秘钥也传入围圈。然后，在CPU的加密保护下利用数据进行运算，结果会以密文形式返回。这种模式下，既可以利用强大的计算力，又不用担心数据泄漏。
如上文所述，通过在TEE中执行解密后的交易内容，可以确保执行过程在可信环境内完成，以确保隐私信息不会发生泄漏。当上述存在隐私处理需求的交易用于创建智能合约时，该交易中包含智能合约的代码，第一区块链节点可以在TEE中对该交易进行解密得到其所含智能合约的代码，并进而在TEE中执行该代码。当上述存在隐私处理需求的交易用于调用智能合约时，第一区块链节点可以在TEE中执行该代码(若被调用的智能合约处理加密状态，则需要先在TEE中对该智能合约进行解密，以得到相应的代码)。具体的，第一区块链节点可以利用CPU中新增的处理器指令，在内存中分配一部分区域EPC，通过CPU内的加密引擎MEE对上述的明文代码进行加密存入所述EPC中。EPC中加密的内容进入CPU后被解密成明文。在CPU中，对明文的代码进行运算，完成执行过程。例如，在SGX技术中，执行智能合约的明文代码，可以将EVM加载进围圈中。在远程证明过程中，密钥管理服务器可以计算本地EVM代码的hash值，并与第一区块链节点中加载的EVM代码的hash值比对，比对结果正确作为通过远程证明的一个必要条件，从而完成对第一区块链节点SGX围圈加载的代码的度量。经过度量，正确的EVM可以在SGX中执行上述智能合约的代码。
步骤308，第一区块链节点存储所述收据数据，使对应于所述特殊事件函数的日志中满足预设条件的至少一个日志字段以明文形式存储、所述收据数据的其余内容以密文形式存储。
在一实施例中，针对收据数据中对应于特殊事件函数的日志，可将该日志的所有日志字段均与相应的预设条件进行比较，并将所有满足预设条件的日志字段以明文形式存储。相应的，对于对应于特殊事件函数但为满足预设条件的日志字段、对应于普通事件函数的日志、收据数据中的其他收据内容等，均以密文形式存储。
在一实施例中，针对收据数据中对应于特殊事件函数的日志，可以确定出该特殊事件函数对应的暴露日志字段，并将暴露日志字段与相应的预设条件进行比较，从而将满 足预设条件的暴露日志字段以明文形式存储。暴露日志字段往往涉及到的隐私内容相对较少，或者不涉及到核心隐私内容，以明文形式存储的风险相对较低；而非暴露日志字段可能涉及到相对更多或相对更重要的隐私内容，以密文形式存储可以确保不偏离隐私保护的核心目的。而通过结合预设条件进行判断，可以进一步筛除暴露日志字段可能包含的不适宜公开的隐私内容，从而在保证能够完成检索操作的同时，尽可能地实现隐私保护。
在一实施例中，特殊事件函数中包含通过暴露标识符标明的暴露日志字段。第一区块链节点可以通过读取特殊事件函数所含的暴露标识符，并将该暴露标识符标明的一个或多个日志字段确定为上述的暴露日志字段。以Solidity语言为例，智能合约包含的特殊事件函数的代码示例如下：
Event buy_candy3 expose_from(who,candy_num)；
Event buy_candy4 show_to(who,candy_num)；
在上述代码示例中，智能合约定义了2个事件：事件buy_candy3和事件buy_candy4。
事件buy_candy3中包含类型标识符“expose”，根据上文所述，可以将该事件buy_candy3判定为特殊事件函数。进一步地，在类型标识符“expose”之后包含暴露标识符“_from”，该暴露标识符“_from”用于标明日志字段From，使得在事件buy_candy3对应生成的日志Logs中，From字段将以明文形式存储，而其余的To字段、Topic字段、Log data字段等以密文形式存储。
事件buy_candy4并未包含类型标识符“expose”；但是，如果事件buy_candy4为前述预先定义的特殊事件函数，比如该事件buy_candy4位于前述的特殊事件函数列表中，那么可以判定该事件buy_candy4为特殊事件函数。进一步地，事件buy_candy4中包含暴露标识符“show_to”，该暴露标识符“show_to”用于标明日志字段to，使得在事件buy_candy4对应生成的日志Logs中，To字段将以明文形式存储，而其余的From字段、Topic字段、Log data字段等以密文形式存储。
与暴露标识符标明的暴露日志字段相类似的，特殊事件函数中可以包含通过加密标识符标明的加密日志字段，则暴露日志字段为剩余的其他日志字段。以Solidity语言为例，智能合约包含的特殊事件函数的代码示例如下：
Event buy_candy5 expose_hide_from(who,candy_num)；
Event buy_candy6 hide_to(who,candy_num)；
在上述代码示例中，智能合约定义了2个事件：事件buy_candy5和事件buy_candy6。
事件buy_candy5中包含类型标识符“expose”，根据上文所述，可以将该事件buy_candy5判定为特殊事件函数。进一步地，在类型标识符“expose”之后包含加密标识符“hide_from”，该加密标识符“hide_from”用于标明日志字段From，使得在事件buy_candy5对应生成的日志Logs中，From字段将以密文形式存储，而其余的To字段、Topic字段、Log data字段等为暴露日志字段，均以明文形式存储。
事件buy_candy6并未包含类型标识符“expose”；但是，如果事件buy_candy6为前述预先定义的特殊事件函数，比如该事件buy_candy6位于前述的特殊事件函数列表中，那么可以判定该事件buy_candy6为特殊事件函数。进一步地，事件buy_candy6中包含加密标识符“hide_to”，该加密标识符“hide_to”用于标明日志字段to，使得在事件buy_candy6对应生成的日志Logs中，To字段将以密文形式存储，而其余的From字段、Topic字段、Log data字段等为暴露日志字段，均以明文形式存储。
以太坊支持的高级语言很多，如Solidity、Serpent、LLL语言等，均可以包含上述的暴露/加密标识符。上述的暴露/加密标识符在高级语言和字节码形式的智能合约代码中可以相同，或者高级语言的智能合约代码中为第一暴露/加密标识符、字节码形式的智能合约代码中为第二暴露/加密标识符，第一暴露/加密标识符与第二暴露/加密标识符之间可以相互对应。
除了在特殊事件函数中添加上述的暴露标识符或加密标识符，以指明相应的暴露日志字段之外，可以预先定义特殊事件函数与暴露日志字段之间的映射关系，或者特殊事件函数与加密日志字段之间的映射关系，使得第一区块链节点可以获取预定义的上述映射关系，并根据智能合约包含的特殊事件函数和上述映射关系，确定该特殊事件函数对应的暴露日志字段。
例如，当映射关系中包含“Event buy_candy7-from_to”、“Event buy_candy8-topic”等内容时，若智能合约中包含事件“Event buy_candy7”，则通过查询到上述的映射关系“Event buy_candy7-from_to”，则可以确定该事件“Event buy_candy7”对应的暴露日志字段为From字段和To字段，若智能合约中包含事件“Event buy_candy8”，则通过查询到上述的映射关系“Event buy_candy8-topic”，则可以确定该事件“Event buy_candy8”对应的暴露日志字段为Topic字段。
在一实施例中，在保护用户隐私的前提下，通过对智能合约所含的事件函数予以识 别，可以根据不同类型的事件函数对于隐私保护的差异化需求，确定出可以明文存储的暴露日志字段，并进一步根据暴露日志字段对预设条件的满足情况，在存储过程中体现出相应的差异化需求，具有较高的灵活性。
具体的，通过将特殊事件函数对应的暴露日志字段与预设条件进行比较，可以将满足预设条件的暴露日志字段以明文形式存储，而不满足预设条件的暴露日志字段或其他的收据内容则必然以密文形式存储。其中，预设条件的内容可以包括以下至少之一：相应的日志字段中包含预设内容、相应的日志字段的取值属于预设数值区间等。
预设内容可以包括：指定的一个或多个关键词，比如该关键词可以包括预定义的状态变量、预定义的中间变量等，使得当某一暴露日志字段包含作为关键词的状态变量或中间变量时，可以判定该暴露日志字段满足预设条件。
预设内容可以包括：预设值。比如该预设值可以为数值，该数值可与状态变量的取值等进行比较，以确定状态变量的取值是否符合预期；再比如该预设值可以为数值、字母、特殊符号等构成的字符串，该字符串可与交易发起方的账户地址、交易目标方的账户地址、日志主题等进行比较，以识别出特定的交易发起方、特定的交易目标方或特定的日志主题等。以预设内容为字符串为例，假定该字符串为某一账户地址，可使用户在针对该账户地址发起交易且交易类型对应的暴露日志字段包括To字段时，将To字段采用明文形式存储，而针对其他账户地址发起交易时，To字段不允许采用明文形式存储，避免泄露隐私。
预设数值区间可以表明相关收据字段的隐私保护需求情况，比如在转账场景中，预设数值区间可以为数值较小、隐私保护需求较低的数值区间，使得即便公开相关收据字段也不会造成严重的用户隐私泄露，但可以用于自动触发如DAPP客户端的相关操作，从而在隐私保护与便捷性之间取得一定平衡。因此，当暴露日志字段的取值处于该预设数值区间时，可以将该暴露日志字段以明文形式存储。
在一实施例中，预设条件可以包括所有日志字段对应的通用条件，即在收据数据中对应于特殊事件函数的日志中，该日志所含的所有日志字段存在统一的预设条件，使得该日志所含的所有暴露日志字段均需与该统一的预设条件进行比较。例如，当预设条件为“包含预设关键词”时，可以将特殊事件函数对应的日志中的所有暴露日志字段与该预设条件所含的关键词进行比较，以确定出包含该关键词的暴露日志字段，作为满足上述预设条件的暴露日志字段。
在一实施例中，预设条件可以包括每一日志字段分别对应的专用条件，即在收据数据中对应于特殊事件函数的日志中，该日志所含的各个日志字段分别存在对应的预设条件，使得该日志所含的每一暴露日志字段被用于与对应的预设条件进行比较。不同日志字段对应的预设条件之间相互独立，但可能相同，也可能不同。例如，From字段和To字段对应的预设条件可以为“是否包含预设内容”，且该预设内容可以为预设的账户地址，表明由该账户地址发起或针对该账户地址发起的交易，允许将From字段或To字段以明文形式存储(可以在From字段或To字段属于暴露日志字段时以明文形式存储)。再例如，Topic字段对应的预设条件可以为“是否属于预设取值区间”，而Topic字段中可以记录相关事件引用的状态变量的取值，譬如转账场景下可以包括代表“转账金额”的状态变量，表明转账金额处于预设取值区间(通常可以为较小金额对应的小额数值区间)时，允许将该转账金额以明文形式存储(可以在Topic字段属于暴露日志字段时以明文形式存储)。
在一实施例中，预设条件可以位于交易中，使得不同交易所采用的预设条件可以存在差异，以满足不同交易所面临的需求差异；当然，不同交易也可以采用相同的预设条件。预设条件的不同可以表现为：预设条件的内容、预设条件适用的收据字段、对暴露日志字段是否满足预设条件进行判断的处理逻辑中的至少一个维度的差异。
在一实施例中，预设条件可以位于交易调用的智能合约中，或者预设条件可以位于交易调用的智能合约所调用的另一智能合约中，使得交易可以通过选取所调用的智能合约，以确定是否使用相应的预设条件。智能合约可由交易发起方自身或其他任意用户预先创建；当然，如果智能合约存在相应的调用条件，那么需要在该调用条件被满足时才能够使得上述交易调用该智能合约，比如该调用条件可以包括：交易发起方属于预设白名单、交易发起方不属于预设黑名单或其他条件。
在一实施例中，预设条件可以位于系统合约或链代码中，使得该预设条件为适用于区块链上的所有交易的全局条件，而区别于上述的交易或智能合约所含的预设条件，使得即便交易或交易调用的智能合约并未包含预设条件的情况下，可以基于系统合约或链代码中定义的预设条件，并结合交易发起方的用户类型，确定日志字段的存储方式。
需要指出的是：交易或智能合约所含的预设条件，与链代码或系统合约所含的预设条件之间并不矛盾：两者可以分别包含不同维度的预设条件，比如预设条件适用的日志字段不同；或者，当两者包含的预设条件之间存在冲突时，可以默认为优先采用交易或智能合约所含的预设条件，或者优先采用链代码或系统合约所含的预设条件，这取决于 预定义的选择逻辑。
通过在计算设备(物理机或虚拟机)上运行区块链的程序代码(以下简称为链代码)，可以将该计算设备配置为区块链网络中的区块链节点，比如上述的第一区块链节点等。换言之，第一区块链节点通过运行上述的链代码，以实现相应的功能逻辑。因此，可以在创建区块链网络时，将上文所述的与事件函数和预设条件相关的收据数据存储逻辑写入链代码中，使得各个区块链节点均可以实现该收据数据存储逻辑。
与事件函数和预设条件相关的收据数据存储逻辑可以包括：对特殊事件函数的识别逻辑、对暴露日志字段的确认逻辑、对预设条件的确定逻辑、对暴露日志字段的处理逻辑等。
对特殊事件函数的识别逻辑用于指示第一区块链节点：识别智能合约所含的特殊事件函数。比如：系统合约中可以记录有预定义的特殊事件函数列表，或者系统合约中可以记录有基于类型标识符对特殊事件函数进行识别的处理逻辑。具体可以参考上文中识别特殊事件函数的相关描述，此处不再赘述。
对暴露日志字段的确认逻辑用于指示第一区块链节点：根据特殊事件函数确定对应的暴露日志字段。比如：根据特殊事件函数所含的暴露标识符或加密标识符，确定相应的暴露日志字段；或者，根据链代码或系统合约或区块中记载的特殊事件函数与暴露日志字段之间的映射关系，结合当前发起交易所含的特殊事件函数，确定相应的暴露日志字段。具体可以参考上文中获知特殊事件函数对应的暴露日志字段的相关描述，此处不再赘述。
对预设条件的确定逻辑用于指示第一区块链节点：获取暴露日志字段适用的预设条件。比如：获取适用于所有收据字段的通用条件，或者获取适用于暴露日志字段的专用条件等。具体可以参考上文中预设条件的相关描述，此处不再赘述。
对暴露日志字段的处理逻辑用于指示第一区块链节点：对收据数据中对应于暴露日志字段的收据内容进行存储。比如：对于收据数据中对应于特殊事件函数的日志，可以将该日志中对应于暴露日志字段且满足预设条件的收据内容采用明文形式存储，而将该日志中对应于暴露日志字段且未满足预设条件的收据内容、对应于非暴露字段的收据内容采用密文形式存储，以及将收据数据中的其他收据内容(如普通事件函数对应的收据内容)采用密文形式存储。具体可以参考上文中存储收据数据的相关描述，此处不再赘述。
由于链代码的升级更新相对较为困难，使得采用链代码实现对收据数据的存储存在灵活性低、可扩展性不足的问题。为了实现对链代码的功能扩展，如图5所示，可以采用链代码与系统合约相结合的方式：链代码用于实现区块链网络的基础功能，而运行过程中的功能扩展可以通过系统合约的方式实现。与上述的智能合约相类似的，系统合约包括譬如字节码形式的代码，第一区块链节点可以通过运行系统合约的代码(比如，根据唯一对应的地址“0x53a98…”来读取该系统合约中的代码)，实现对链代码的功能补充。相应地，第一区块链节点可以读取系统合约的代码，该系统合约的代码中定义了与交易类型和事件函数相关的收据数据存储逻辑；然后，第一区块链节点可以执行系统合约的代码，从而基于与事件函数和预设条件相关的收据数据存储逻辑，将对应于特殊事件函数的日志中满足预设条件的暴露日志字段以明文形式存储、收据数据的其余内容以密文形式存储。
区别于上述由用户发布至区块链的智能合约，系统合约无法由用户自由发布。第一区块链节点读取的系统合约可以包括配置于区块链网络的创世块中的预置系统合约；以及，区块链网络中的管理员(即上述的管理用户)可以具有针对系统合约的更新权限，从而针对诸如上述的预置系统合约进行更新，则上述第一区块链节点读取的系统合约还可以包括相应的更新后系统合约。当然，更新后系统合约可以由管理员对预置系统合约实施一次更新后得到；或者，更新后系统合约可以由管理员对预置系统合约实施多次迭代更新后得到，比如由预置系统合约更新得到系统合约1、对系统合约1更新得到系统合约2、对系统合约2更新得到系统合约3，该系统合约1、系统合约2、系统合约3均可以视为更新后系统合约，但第一区块链节点通常会以最新版本的系统合约为准，比如第一区块链节点会以系统合约3中的代码为准，而非系统合约1或系统合约2中的代码。
除了创世块中包含的预置系统合约之外，管理员还可以在后续区块内发布系统合约，以及针对所发布的系统合约进行更新。总之，应当通过诸如权限管理等方式，对系统合约的发布和更新实施一定程度的限制，以确保区块链网络的功能逻辑能够正常运作，并且避免对任何用户造成不必要的损失。
对于收据数据中需要以密文形式存储的收据内容，第一区块链节点通过密钥对这些收据内容进行加密。所述加密，可以采用对称加密，也可以采用非对称加密。如果第一区块链节点用对称加密方式，即用对称加密算法的对称密钥对收据内容加密，则客户端(或其他持有密钥的对象)可以用该对称加密算法的对称密钥对加密后的收据内容 进行解密。
在一实施例中，第一区块链节点用对称加密算法的对称密钥对收据内容进行加密时，该对称密钥可由客户端预先提供至第一区块链节点。那么，由于只有客户端(实际应当为客户端上的已登录账户对应的用户)和第一区块链节点掌握该对称密钥，使得仅该客户端能够解密相应的加密后的收据内容，避免无关用户甚至不法分子对加密后的收据内容进行解密。
例如，客户端在向第一区块链节点发起交易时，客户端可以用对称加密算法的初始密钥对交易内容进行加密，以得到该交易；相应地，第一区块链节点可以通过获得该初始密钥，以用于直接或间接对收据内容进行加密。譬如，该初始密钥可以由客户端与第一区块链节点预先协商得到，或者由密钥管理服务器发送至客户端和第一区块链节点，或者由客户端发送至第一区块链节点。当初始密钥由客户端发送至第一区块链节点时，客户端可以通过非对称加密算法的公钥对该初始密钥进行加密后，将加密后的初始密钥发送至第一区块链节点，而第一区块链节点通过非对称加密算法的私钥对该加密后的初始密钥进行解密，得到初始密钥，即上文所述的数字信封加密，此处不再赘述。
在一实施例中，第一区块链节点可以采用上述的初始密钥对收据内容进行加密。不同交易采用的初始密钥可以相同，使得同一用户所提交的所有交易均采用该初始密钥进行加密，或者不同交易采用的初始密钥可以不同，比如客户端可以针对每一交易随机生成一初始密钥，以提升安全性。
在一实施例中，第一区块链节点可以根据初始密钥与影响因子生成衍生密钥，并通过该衍生密钥对收据内容进行加密。相比于直接采用初始密钥进行加密，衍生密钥可以增加随机度，从而提升被攻破的难度，有助于优化数据的安全保护。影响因子可以与交易相关；例如，影响因子可以包括交易哈希值的指定位，比如第一区块链节点可以将初始密钥与交易哈希值的前16位(或前32位、后16位、后32位，或者其他位)进行拼接，并对拼接后的字符串进行哈希运算，从而生成衍生密钥。
在一实施例中，第一区块链节点还可以采用非对称加密方式，即用非对称加密算法的公钥对收据内容加密，则相应地，客户端可以用所述非对称加密算法的私钥解密上述加密后的收据内容。非对称加密算法的密钥，例如可以是由客户端生成一对公钥和私钥，并将公钥预先发送至第一区块链节点，从而第一区块链节点可以将收据内容用该公钥加密。
第一区块链节点通过运行用于实现某一功能的代码，以实现该功能。因此，对于需要在TEE中实现的功能，同样需要执行相关代码。而对于在TEE中执行的代码，需要符合TEE的相关规范和要求；相应地，对于相关技术中用于实现某一功能的代码，需要结合TEE的规范和要求重新进行代码编写，不仅存在相对更大的开发量，而且容易在重新编写过程中产生漏洞(bug)，影响功能实现的可靠性和稳定性。
因此，第一区块链节点可以通过在TEE之外执行存储功能代码，将TEE中生成的收据数据(包括需要明文存储的明文形式的收据内容，以及需要密文存储的密文形式的收据内容)存储至TEE之外的外部存储空间，使得该存储功能代码可以为相关技术中用于实现存储功能的代码、不需要结合TEE的规范和要求重新进行代码编写，即可针对收据数据实现安全可靠的存储，不仅可以在不影响安全、可靠程度的基础上，减少相关代码的开发量，而且可以通过减少TEE的相关代码而降低TCB(Trusted Computing Base，可信计算基)，使得TEE技术与区块链技术进行结合的过程中，额外造成的安全风险处于可控范围。
在一实施例中，第一区块链节点可以在TEE内执行写缓存功能代码，以将上述的收据数据存入TEE内的写缓存中，比如该写缓存可以对应于如图1所示的“缓存”。进一步的，第一区块链节点将写缓存中的数据从可信执行环境输出，以存储至外部存储空间。其中，写缓存功能代码可以以明文形式存储于TEE中，可以直接在TEE中执行该明文形式的缓存功能代码；或，写缓存功能代码可以以密文形式存储于TEE之外，比如存储于上述的外部存储空间(比如图4所示的“打包+存储”，其中“打包”表示第一区块链节点在可信执行环境之外对交易进行打包成块)，可以将该密文形式的写缓存功能代码读入TEE、在TEE中进行解密为明文代码，并执行该明文代码。
写缓存是指在将数据写入外部存储空间时，为了避免造成对外部存储空间的“冲击”而提供的“缓冲”机制。例如，可以采用buffer实现上述的写缓存；当然，写缓存也可以采用cache来实现，本说明书并不对此进行限制。实际上，由于TEE为隔离的安全环境，而外部存储空间位于TEE之外，使得通过采用写缓存机制，可以对缓存内的数据进行批量写入外部存储空间，从而减少TEE与外部存储空间之间的交互次数，提升数据存储效率。同时，TEE在不断执行各条交易的过程中，可能需要调取已生成的数据，如果需调用的数据恰好位于写缓存中，可以直接从写缓存中读取该数据，这样一方面可以减少与外部存储空间之间的交互，另一方面免去了对从外部存储空间所读取数据的解密过程，从而提升在TEE中的数据处理效率。
当然，也可以将写缓存建立于TEE之外，比如第一区块链节点可以在TEE之外执行写缓存功能代码，从而将上述的收据数据存入TEE外的写缓存中，并进一步将写缓存中的数据存储至外部存储空间。
以下结合图6介绍本说明书一种结合事件函数类型和判断条件的收据存储节点的实施例，包括：
接收单元61，接收经过加密的调用智能合约的交易；
解密单元62，在可信执行环境中解密所述交易以获得所述智能合约，所述智能合约包含特殊事件函数；
执行单元63，在所述可信执行环境中执行所述智能合约，得到收据数据，所述收据数据包含对应于所述特殊事件函数的日志；
存储单元64，存储所述收据数据，使对应于所述特殊事件函数的日志中满足预设条件的至少一个日志字段以明文形式存储、所述收据数据的其余内容以密文形式存储。
可选的，所述智能合约中的事件函数包含类型标识符，所述类型标识符用于将所述事件函数标记为特殊事件函数。
可选的，当所述智能合约包含的事件函数位于区块链上记录的特殊函数列表中时，所述智能合约包含的事件函数被判定为特殊事件函数。
可选的，所述至少一个日志字段包括：所述特殊事件函数对应的暴露日志字段。
可选的，所述特殊事件函数中包含通过暴露标识符标明的所述暴露日志字段；或者，所述特殊事件函数中包含通过加密标识符标明的加密日志字段，所述暴露日志字段为其他日志字段。
可选的，区块链中记录有预定义的特殊事件函数与暴露日志字段之间的映射关系，或者预定义的特殊事件函数与加密日志字段之间的映射关系；所述映射关系被用于确定所述特殊事件函数对应的暴露日志字段。
可选的，所述预设条件包括以下至少之一：相应的日志字段中包含预设内容、相应的日志字段的取值属于预设数值区间。
可选的，
所述预设条件包括所有日志字段对应的通用条件；或，
所述预设条件包括每一日志字段分别对应的专用条件。
可选的，
所述预设条件位于所述交易中；或，
所述预设条件位于所述交易调用的智能合约中，或所述交易调用的智能合约所调用的另一智能合约中；或，
所述预设条件位于系统合约或链代码中。
可选的，存储单元64具体用于：
读取系统合约的代码，所述系统合约的代码中定义了与事件函数和预设条件相关的收据数据存储逻辑；
执行所述系统合约的代码，以将对应于所述特殊事件函数的日志中满足预设条件的至少一个日志字段以明文形式存储、所述收据数据的其余内容以密文形式存储。
可选的，所述系统合约包括：记录于创世块中的预置系统合约，或所述预置系统合约对应的更新后系统合约。
可选的，存储单元64具体用于：
在所述可信执行环境之外执行存储功能代码，以将所述收据数据存储至所述可信执行环境之外的外部存储空间。
可选的，第一区块链节点对所述收据数据进行加密的密钥包括：对称加密算法的密钥或非对称加密算法的密钥。
可选的，所述对称加密算法的密钥包括所述客户端提供的初始密钥；或，所述对称加密算法的密钥包括所述初始密钥与影响因子生成的衍生密钥。
可选的，所述交易由所述初始密钥进行加密，且所述初始密钥被非对称加密算法的公钥进行加密；解密单元62具体用于：
用所述非对称加密算法的私钥解密得到所述初始密钥，并用所述初始密钥对所述交易进行解密，以得到所述交易内容。
可选的，所述初始密钥由客户端生成；或，所述初始密钥由密钥管理服务器发送至所述客户端。
可选的，所述影响因子与所述交易相关。
可选的，所述影响因子包括：所述交易的哈希值的指定位。
在20世纪90年代，对于一个技术的改进可以很明显地区分是硬件上的改进(例如，对二极管、晶体管、开关等电路结构的改进)还是软件上的改进(对于方法流程的改进)。然而，随着技术的发展，当今的很多方法流程的改进已经可以视为硬件电路结构的直接改进。设计人员几乎都通过将改进的方法流程编程到硬件电路中来得到相应的硬件电路结构。因此，不能说一个方法流程的改进就不能用硬件实体模块来实现。例如，可编程逻辑器件(Programmable Logic Device,PLD)(例如现场可编程门阵列(Field Programmable Gate Array，FPGA))就是这样一种集成电路，其逻辑功能由用户对器件编程来确定。由设计人员自行编程来把一个数字系统“集成”在一片PLD上，而不需要请芯片制造厂商来设计和制作专用的集成电路芯片。而且，如今，取代手工地制作集成电路芯片，这种编程也多半改用“逻辑编译器(logic compiler)”软件来实现，它与程序开发撰写时所用的软件编译器相类似，而要编译之前的原始代码也得用特定的编程语言来撰写，此称之为硬件描述语言(Hardware Description Language，HDL)，而HDL也并非仅有一种，而是有许多种，如ABEL(Advanced Boolean Expression Language)、AHDL(Altera Hardware Description Language)、Confluence、CUPL(Cornell University Programming Language)、HDCal、JHDL(Java Hardware Description Language)、Lava、Lola、MyHDL、PALASM、RHDL(Ruby Hardware Description Language)等，目前最普遍使用的是VHDL(Very-High-Speed Integrated Circuit Hardware Description Language)与Verilog。本领域技术人员也应该清楚，只需要将方法流程用上述几种硬件描述语言稍作逻辑编程并编程到集成电路中，就可以很容易得到实现该逻辑方法流程的硬件电路。
控制器可以按任何适当的方式实现，例如，控制器可以采取例如微处理器或处理器以及存储可由该(微)处理器执行的计算机可读程序代码(例如软件或固件)的计算机可读介质、逻辑门、开关、专用集成电路(Application Specific Integrated Circuit，ASIC)、可编程逻辑控制器和嵌入微控制器的形式，控制器的例子包括但不限于以下微控制器：ARC 625D、Atmel AT91SAM、Microchip PIC18F26K20以及Silicone Labs C8051F320，存储器控制器还可以被实现为存储器的控制逻辑的一部分。本领域技术人员也知道，除了以纯计算机可读程序代码方式实现控制器以外，完全可以通过将方法步骤进行逻辑编程来使得控制器以逻辑门、开关、专用集成电路、可编程逻辑控制器和嵌入微控制器等的形式来实现相同功能。因此这种控制器可以被认为是一种硬件部件，而对其内包括的用于实现各种功能的装置也可以视为硬件部件内的结构。或者甚至，可以将用于实现各种功能的装置视为既可以是实现方法的软件模块又可以是硬件部件内的 结构。
上述实施例阐明的系统、装置、模块或单元，具体可以由计算机芯片或实体实现，或者由具有某种功能的产品来实现。一种典型的实现设备为计算机。具体的，计算机例如可以为个人计算机、膝上型计算机、蜂窝电话、相机电话、智能电话、个人数字助理、媒体播放器、导航设备、电子邮件设备、游戏控制台、平板计算机、可穿戴设备或者这些设备中的任何设备的组合。
为了描述的方便，描述以上装置时以功能分为各种单元分别描述。当然，在实施本说明书时可以把各单元的功能在同一个或多个软件和/或硬件中实现。
本领域内的技术人员应明白，本发明的实施例可提供为方法、系统、或计算机程序产品。因此，本发明可采用完全硬件实施例、完全软件实施例、或结合软件和硬件方面的实施例的形式。而且，本发明可采用在一个或多个其中包含有计算机可用程序代码的计算机可用存储介质(包括但不限于磁盘存储器、CD-ROM、光学存储器等)上实施的计算机程序产品的形式。
本发明是参照根据本发明实施例的方法、设备(系统)、和计算机程序产品的流程图和/或方框图来描述的。应理解可由计算机程序指令实现流程图和/或方框图中的每一流程和/或方框、以及流程图和/或方框图中的流程和/或方框的结合。可提供这些计算机程序指令到通用计算机、专用计算机、嵌入式处理机或其他可编程数据处理设备的处理器以产生一个机器，使得通过计算机或其他可编程数据处理设备的处理器执行的指令产生用于实现在流程图一个流程或多个流程和/或方框图一个方框或多个方框中指定的功能的装置。
本说明书可以在由计算机执行的计算机可执行指令的一般上下文中描述，例如程序模块。一般地，程序模块包括执行特定任务或实现特定抽象数据类型的例程、程序、对象、组件、数据结构等等。也可以在分布式计算环境中实践本说明书，在这些分布式计算环境中，由通过通信网络而被连接的远程处理设备来执行任务。在分布式计算环境中，程序模块可以位于包括存储设备在内的本地和远程计算机存储介质中。
这些计算机程序指令也可存储在能引导计算机或其他可编程数据处理设备以特定方式工作的计算机可读存储器中，使得存储在该计算机可读存储器中的指令产生包括指令装置的制造品，该指令装置实现在流程图一个流程或多个流程和/或方框图一个方框或多个方框中指定的功能。
这些计算机程序指令也可装载到计算机或其他可编程数据处理设备上，使得在计算机或其他可编程设备上执行一系列操作步骤以产生计算机实现的处理，从而在计算机或其他可编程设备上执行的指令提供用于实现在流程图一个流程或多个流程和/或方框图一个方框或多个方框中指定的功能的步骤。在一个典型的配置中，计算机包括一个或多个处理器(CPU)、输入/输出接口、网络接口和内存。
内存可能包括计算机可读介质中的非永久性存储器，随机存取存储器(RAM)和/或非易失性内存等形式，如只读存储器(ROM)或闪存(flash RAM)。内存是计算机可读介质的示例。
计算机可读介质包括永久性和非永久性、可移动和非可移动媒体可以由任何方法或技术来实现信息存储。信息可以是计算机可读指令、数据结构、程序的模块或其他数据。计算机的存储介质的例子包括，但不限于相变内存(PRAM)、静态随机存取存储器(SRAM)、动态随机存取存储器(DRAM)、其他类型的随机存取存储器(RAM)、只读存储器(ROM)、电可擦除可编程只读存储器(EEPROM)、快闪记忆体或其他内存技术、只读光盘只读存储器(CD-ROM)、数字多功能光盘(DVD)或其他光学存储、磁盒式磁带、磁盘存储、量子存储器、基于石墨烯的存储介质或其他磁性存储设备或任何其他非传输介质，可用于存储可以被计算设备访问的信息。按照本文中的界定，计算机可读介质不包括暂存电脑可读媒体(transitory media)，如调制的数据信号和载波。
还需要说明的是，术语“包括”、“包含”或者其任何其他变体意在涵盖非排他性的包含，从而使得包括一系列要素的过程、方法、商品或者设备不仅包括那些要素，而且还包括没有明确列出的其他要素，或者是还包括为这种过程、方法、商品或者设备所固有的要素。在没有更多限制的情况下，由语句“包括一个……”限定的要素，并不排除在包括所述要素的过程、方法、商品或者设备中还存在另外的相同要素。
上述对本说明书特定实施例进行了描述。其它实施例在所附权利要求书的范围内。在一些情况下，在权利要求书中记载的动作或步骤可以按照不同于实施例中的顺序来执行并且仍然可以实现期望的结果。另外，在附图中描绘的过程不一定要求示出的特定顺序或者连续顺序才能实现期望的结果。在某些实施方式中，多任务处理和并行处理也是可以的或者可能是有利的。
在本说明书一个或多个实施例使用的术语是仅仅出于描述特定实施例的目的，而非旨在限制本说明书一个或多个实施例。在本说明书一个或多个实施例和所附权利要求书中所使用的单数形式的“一种”、“所述”和“该”也旨在包括多数形式，除非上 下文清楚地表示其他含义。还应当理解，本文中使用的术语“和/或”是指并包含一个或多个相关联的列出项目的任何或所有可能组合。
应当理解，尽管在本说明书一个或多个实施例可能采用术语第一、第二、第三等来描述各种信息，但这些信息不应限于这些术语。这些术语仅用来将同一类型的信息彼此区分开。例如，在不脱离本说明书一个或多个实施例范围的情况下，第一信息也可以被称为第二信息，类似地，第二信息也可以被称为第一信息。取决于语境，如在此所使用的词语“如果”可以被解释成为“在……时”或“当……时”或“响应于确定”。
以上所述仅为本说明书一个或多个实施例的较佳实施例而已，并不用以限制本说明书一个或多个实施例，凡在本说明书一个或多个实施例的精神和原则之内，所做的任何修改、等同替换、改进等，均应包含在本说明书一个或多个实施例保护的范围之内。

Claims (21)

  1. 一种结合事件函数类型和判断条件的收据存储方法，包括：
    第一区块链节点接收经过加密的调用智能合约的交易；
    第一区块链节点在可信执行环境中解密所述交易以获得所述智能合约，所述智能合约包含特殊事件函数；
    第一区块链节点在所述可信执行环境中执行所述智能合约，得到收据数据，所述收据数据包含对应于所述特殊事件函数的日志；
    第一区块链节点存储所述收据数据，使对应于所述特殊事件函数的日志中满足预设条件的至少一个日志字段以明文形式存储、所述收据数据的其余内容以密文形式存储。
  2. 根据权利要求1所述的方法，所述智能合约中的事件函数包含类型标识符，所述类型标识符用于将所述事件函数标记为特殊事件函数。
  3. 根据权利要求1所述的方法，当所述智能合约包含的事件函数位于区块链上记录的特殊函数列表中时，所述智能合约包含的事件函数被判定为特殊事件函数。
  4. 根据权利要求1所述的方法，所述至少一个日志字段包括：所述特殊事件函数对应的暴露日志字段。
  5. 根据权利要求4所述的方法，所述特殊事件函数中包含通过暴露标识符标明的所述暴露日志字段；或者，所述特殊事件函数中包含通过加密标识符标明的加密日志字段，所述暴露日志字段为其他日志字段。
  6. 根据权利要求4所述的方法，区块链中记录有预定义的特殊事件函数与暴露日志字段之间的映射关系，或者预定义的特殊事件函数与加密日志字段之间的映射关系；所述映射关系被用于确定所述特殊事件函数对应的暴露日志字段。
  7. 根据权利要求1所述的方法，所述预设条件包括以下至少之一：相应的日志字段中包含预设内容、相应的日志字段的取值属于预设数值区间。
  8. 根据权利要求1所述的方法，
    所述预设条件包括所有日志字段对应的通用条件；或，
    所述预设条件包括每一日志字段分别对应的专用条件。
  9. 根据权利要求1所述的方法，
    所述预设条件位于所述交易中；或，
    所述预设条件位于所述交易调用的智能合约中，或所述交易调用的智能合约所调用的另一智能合约中；或，
    所述预设条件位于系统合约或链代码中。
  10. 根据权利要求1所述的方法，第一区块链节点存储所述收据数据，包括：
    第一区块链节点读取系统合约的代码，所述系统合约的代码中定义了与事件函数和预设条件相关的收据数据存储逻辑；
    第一区块链节点执行所述系统合约的代码，以将对应于所述特殊事件函数的日志中满足预设条件的至少一个日志字段以明文形式存储、所述收据数据的其余内容以密文形式存储。
  11. 根据权利要求10所述的方法，所述系统合约包括：记录于创世块中的预置系统合约，或所述预置系统合约对应的更新后系统合约。
  12. 根据权利要求1所述的方法，第一区块链节点存储所述收据数据，包括：
    第一区块链节点在所述可信执行环境之外执行存储功能代码，以将所述收据数据存储至所述可信执行环境之外的外部存储空间。
  13. 根据权利要求1所述的方法，第一区块链节点对所述收据数据进行加密的密钥包括：对称加密算法的密钥或非对称加密算法的密钥。
  14. 根据权利要求13所述的方法，所述对称加密算法的密钥包括所述客户端提供的初始密钥；或，所述对称加密算法的密钥包括所述初始密钥与影响因子生成的衍生密钥。
  15. 根据权利要求14所述的方法，所述交易由所述初始密钥进行加密，且所述初始密钥被非对称加密算法的公钥进行加密；第一区块链节点在可信执行环境中解密所述交易，包括：
    第一区块链节点用所述非对称加密算法的私钥解密得到所述初始密钥，并用所述初始密钥对所述交易进行解密，以得到所述交易内容。
  16. 根据权利要求14所述的方法，所述初始密钥由客户端生成；或，所述初始密钥由密钥管理服务器发送至所述客户端。
  17. 根据权利要求14所述的方法，所述影响因子与所述交易相关。
  18. 根据权利要求17所述的方法，所述影响因子包括：所述交易的哈希值的指定位。
  19. 一种结合事件函数类型和判断条件的收据存储节点，包括：
    接收单元，接收经过加密的调用智能合约的交易；
    解密单元，在可信执行环境中解密所述交易以获得所述智能合约，所述智能合约包含特殊事件函数；
    执行单元，在所述可信执行环境中执行所述智能合约，得到收据数据，所述收据数 据包含对应于所述特殊事件函数的日志；
    存储单元，存储所述收据数据，使对应于所述特殊事件函数的日志中满足预设条件的至少一个日志字段以明文形式存储、所述收据数据的其余内容以密文形式存储。
  20. 一种电子设备，包括：
    处理器；
    用于存储处理器可执行指令的存储器；
    其中，所述处理器通过运行所述可执行指令以实现如权利要求1-18中任一项所述的方法。
  21. 一种计算机可读存储介质，其上存储有计算机指令，该指令被处理器执行时实现如权利要求1-18中任一项所述方法的步骤。
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