Key security management method of cold wallet and cold wallet server end

Abstract

A key security management method of a cold wallet and a cold wallet server, a user provides a mnemonic word to generate a key and a wallet address, and then the system stores the key fragments in different storage addresses of volatile memory, such as memory. Even if the cold wallet server is invaded and the memory data is leaked, the entire key information will not be leaked, that is, the invasion can only obtain part of the key fragments, and cannot piece together the complete key to manipulate the cold wallet assets, greatly reducing the overall key leakage risk caused by local security problems. Moreover, if the cold wallet server detects illegal intrusion, it will start system restart or power-off protection measures. Once the system restarts or powers off, the key fragment data stored in the memory will also disappear, further improving the security and reliability of key protection.

Description

Technical Field

[0001] This invention relates to a method for managing cold wallet keys, specifically a method for secure key management of cold wallets and a cold wallet server. Background Technology

[0002] A private key is the unique credential a user uses to access and control their cryptocurrency wallet. In cryptocurrency transactions, the private key is used to digitally sign transactions, proving the identity of the transaction initiator and the authenticity and integrity of the transaction. Since cryptocurrency transactions are conducted through a blockchain network, the private key is crucial for verifying the legitimacy of the transaction. If the private key is leaked, hackers can impersonate users to conduct transactions and transfer their cryptocurrency, resulting in asset loss. Private keys are typically stored in the user's digital wallet, which is usually categorized as a hot wallet or a cold wallet.

[0003] Hot wallets store private keys on internet-connected devices such as phones and computers, managing them through software and maintaining constant internet interaction. This makes them extremely convenient, allowing users to manage cryptocurrency anytime, anywhere via internet-connected devices, performing transfers, checking balances, and other operations as easily as using online banking. However, because hot wallets rely on internet-connected devices, malicious software can easily infiltrate and obtain private keys. Once obtained, hackers can easily transfer cryptocurrency assets from the user's wallet, causing serious financial losses.

[0004] Cold wallets primarily store private keys on offline devices, such as dedicated hardware wallets, specialized USB storage devices, or paper wallets. However, with recent technological advancements, cold wallets employing one-way communication technology have broken the traditional communication model between cold wallets and the outside world. They utilize the one-way transmission characteristics of the physical layer to allow data to flow from the cold wallet outwards, while preventing external data from flowing back into the cold wallet. However, one-way communication technology is not entirely reliable. While it prevents external data from entering the cold wallet, malicious software may intercept data during outward transmission, attempting to analyze and obtain private key information, thus posing a risk of private key leakage. Therefore, appropriate encryption technologies are needed for the cold wallet server located on the internal network to further enhance the reliability and security of cold wallets using one-way communication technology. Summary of the Invention

[0005] The purpose of this invention is to provide a key security management method for cold wallets and a cold wallet server to improve the reliability and security of cold wallets.

[0006] To achieve the above objectives, the present invention provides the following technical solution: The key security management method of cold wallets includes a cold wallet server isolated from the external network. The cold wallet server first generates a key and wallet address based on the mnemonic phrase. Then, the system will divide the key according to the set key splitting algorithm to obtain two or more key fragments, and store the key fragments in volatile memory at different storage addresses in the cold wallet server. During the signing process, the cold wallet server reads the key fragments from the volatile memory at the corresponding storage address, merges them to obtain the complete key, signs the document, and then deletes the key.

[0007] Furthermore, the storage address of the key fragment and the wallet address are mapped by performing encryption operations on the wallet address.

[0008] Furthermore, the encryption operation is to obtain the hash value by performing two or more hashing algorithms on the wallet address, and then index the obtained hash value with the storage address of the key fragment.

[0009] Furthermore, the key segmentation algorithm is to obtain multiple key fragments corresponding to the number of fragments by performing a reversible operation on the key according to the number of fragments. During signing, the complete key is obtained by performing the inverse operation on the key segmentation algorithm.

[0010] Furthermore, the cold wallet server stores a whitelist of addresses. When a transaction is received by the cold wallet server, the server checks the wallet address against the whitelisted address. If the address matches the whitelisted address, the server reads the key fragments from the volatile memory corresponding to the wallet address and merges them to obtain the complete key for signing.

[0011] A cold wallet server-side component of a key security management method based on a cold wallet includes at least one cold wallet server, a wallet database, and an intranet terminal device. The volatile storage is a memory device installed in the cold wallet server or the wallet database. When the cold wallet server powers on, it reads the mnemonic phrase from the wallet database to generate a key and divides it into key fragments. The different key fragments are stored in memory devices at different storage addresses. During signing, the cold wallet server reads the key fragments from the corresponding memory device, merges them to obtain a complete key for signing, and then deletes the key. The method ensures that when the memory device of the cold wallet server or the wallet database loses power, the memory device loses all key fragments due to power failure.

[0012] Furthermore, the cold wallet server is connected to an external network via a one-way gate communication system. The one-way gate communication system has an internal network interface machine on one side of the cold wallet server for processing and separating incoming and uploaded data, and an external network interface machine on the other side of the external network for separating incoming and uploaded data. The one-way gate communication system includes a set of one-way incoming optical gate devices that unidirectionally transmit external network data to the cold wallet server and a set of one-way uploading optical gate devices that unidirectionally upload data from the cold wallet server to the external network.

[0013] Furthermore, the unidirectional input optical shutter device and the unidirectional output optical shutter device, in order of data transmission direction, include an optical shutter front-end unit, a unidirectional optical shutter, and an optical shutter back-end unit.

[0014] Furthermore, the upstream of the external network interface machine is connected to the external network firewall before connecting to the external network.

[0015] Furthermore, an internal network firewall is installed between the internal network interface and the cold wallet server.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: When a user logs into the cold wallet server, a key and wallet address are generated using the user-provided mnemonic phrase. The system then stores key fragments in volatile memory, such as RAM, at different storage locations. Even if the cold wallet server is compromised, resulting in the leakage of memory data, the entire key information will not be leaked. In other words, the intruder can only obtain partial key fragments and cannot assemble the complete key to control cold wallet assets, greatly reducing the risk of overall key leakage due to localized security issues. Furthermore, if the cold wallet server detects unauthorized intrusion, it will initiate system restart or power-off protection measures. Once the system restarts or loses power, the key fragment data stored in memory will also disappear, further enhancing the security and reliability of key protection. Attached Figure Description

[0017] Figure 1 A flowchart illustrating the workflow for generating key fragments for the cold wallet server of this invention.

[0018] Figure 2 A flowchart illustrating the transaction signing process of the cold wallet server in this invention.

[0019] Figure 3 This is a schematic diagram of the system architecture of the cold wallet server of the present invention. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0021] The cold wallet server consists of a cold wallet server, a wallet database, and internal network terminal devices used to operate the wallet server, all located on an intranet. The cold wallet server connects to an intranet interface machine behind a firewall, and then to an external interface machine via a one-way gate communication system. The external interface machine connects to the external network through a firewall. The one-way gate communication system transmits request data from the external network and return data from both the internal and external networks through different links, making it difficult for network attacks to inject malware or launch vulnerability attacks into the target system using conventional methods. Specifically, the one-way gate communication system includes a set of one-way incoming optical gate devices that unidirectionally transmit data from the external network to the cold wallet server, and a set of one-way uploading optical gate devices that unidirectionally upload data from the cold wallet server to the external network. The external and internal interface machines are devices that separate and integrate request and return data. The one-way incoming and one-way uploading optical gate devices, in order of data transmission direction, include a front-end optical gate, a one-way optical gate, and a back-end optical gate.

[0022] When a user needs to conduct a cryptocurrency transaction, the relevant request is transmitted via the external network. This request is transmitted unidirectionally through a firewall, an external network interface machine, a one-way optical gateway device's front-end and back-end machines, and then through the firewall via an internal network interface machine to the cold wallet server. The cold wallet server generates a key and wallet address based on the mnemonic phrase provided in the user's request. The system then splits the key according to a pre-defined key splitting algorithm, obtaining two or more key fragments. These fragments are stored separately in memory devices at different storage addresses on the cold wallet server or in the wallet database, awaiting a signature request from the user. If the user sends a signature request to the cold wallet server, the server reads the key fragments from the corresponding memory device, merges them to obtain the complete key, and uses this key to sign the transaction. When the transaction is completed or the user logs out of the cold wallet server, the relevant key is deleted. Therefore, even if the cold wallet server is compromised and its memory data is leaked, the entire key information will not be leaked. In other words, the intruder can only obtain partial key fragments and cannot assemble the complete key to control the cold wallet assets, greatly reducing the risk of overall key leakage due to local security issues. Furthermore, if the cold wallet server detects an unauthorized intrusion, it will initiate system restart or power outage protection measures. Once the system restarts or loses power, the key fragment data stored in memory will also disappear, further improving the security and reliability of key protection.

[0023] The storage address of the key slices obtained after key segmentation also needs to undergo encryption. Specifically, the wallet address is encrypted to obtain an encrypted storage address, and a mapping table is formed between the encrypted storage address and the actual memory address of the key slice. The specific encryption method uses hash algorithms, including MD5, MD5 with salt, SHA-1, SHA-256, and SHA-512. Taking MD5 as an example, the hash value obtained by performing multiple MD5 operations on the wallet address is the encrypted storage address.

[0024] Regarding key segmentation, the system determines the number of slices to be less than the key length. Then, the key is segmented using appropriate operations. When a signature is required, the key slices are merged using the inverse operation to form a complete key polarity signature.

[0025] The calculation methods can be: (1) extracting data at intervals, such as extracting data by parity; (2) dividing in the middle, such as dividing the key at the midpoint of the key length, and then dividing again at the midpoint of the above division until the number of slices is met; (3) continuous extraction, extracting a segment of data along the length of the key as a key slice. Of course, the above segmentation methods are not all of them. The system can adopt one, multiple or a combination of multiple segmentation methods according to the needs of use.

[0026] To further improve the reliability and security of the system, a whitelist verification mechanism has been added to the cold wallet server. The cold wallet server stores a whitelist of addresses. When a transaction is sent to the cold wallet server, the server checks the wallet address against the whitelist address. If the address matches the whitelist address, the server reads the key fragment from the memory of the storage address corresponding to the wallet address and merges them to obtain the complete key for signing.

[0027] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for secure key management of a cold wallet, characterized in that: This includes a cold wallet server isolated from the external network. The cold wallet server first generates a key and wallet address based on the mnemonic phrase. Then, the system will divide the key according to the set key splitting algorithm to obtain two or more key fragments, and store the key fragments in volatile memory at different storage addresses in the cold wallet server. During the signing process, the cold wallet server reads the key fragments from the volatile memory at the corresponding storage address, merges them to obtain the complete key, signs the document, and then deletes the key.

2. The key security management method for a cold wallet according to claim 1, characterized in that: The storage address of the key fragment and the wallet address are mapped by performing encryption operations on the wallet address.

3. The key security management method for a cold wallet according to claim 2, characterized in that: The encryption operation is to perform two or more hashing operations on the wallet address to obtain the hash value, and then index the obtained hash value with the storage address of the key fragment.

4. The key security management method for a cold wallet according to claim 1, characterized in that: The key segmentation algorithm is to perform a reversible operation on the key according to the number of slices to obtain multiple key fragments corresponding to the number of slices. During signing, the key segmentation algorithm is reversed to obtain the complete key.

5. The key security management method for a cold wallet according to claim 1, characterized in that: The cold wallet server stores a whitelist of addresses. When a transaction is sent to the cold wallet server, the server checks the wallet address against the whitelisted address. If the address matches the whitelisted address, the server reads the key fragments from the volatile memory corresponding to the wallet address and merges them to obtain the complete key for signing.

6. A cold wallet server based on the key security management method for a cold wallet as described in claim 1, characterized in that: It includes at least one cold wallet server, one wallet database, and intranet terminal devices; the volatile storage is a memory device set in the cold wallet server or the wallet database; the cold wallet server generates a key based on the mnemonic phrase provided by the user and divides it into key fragments, storing different key fragments in memory devices at different storage addresses; during signing, the cold wallet server reads the key fragments from the memory device at the corresponding storage address, merges them to obtain the complete key for signing, and then deletes the key; This setting ensures that when the cold wallet server or wallet database memory device loses power, the memory device loses all key fragments due to power failure.

7. A cold wallet server according to claim 6, characterized in that: The cold wallet server is connected to the external network through a one-way gate communication system. The one-way gate communication system has an internal network interface machine on one side of the cold wallet server for processing and separating incoming and uploaded data, and an external network interface machine on the other side of the external network for separating incoming and uploaded data. The one-way gate communication system includes a set of one-way incoming optical gate devices that unidirectionally transmit external network data to the cold wallet server and a set of one-way uploading optical gate devices that unidirectionally upload data from the cold wallet server to the external network.

8. A cold wallet server according to claim 7, characterized in that: The unidirectional input optical shutter device and the unidirectional output optical shutter device, in order of data transmission direction, include an optical shutter front-end unit, a unidirectional optical shutter, and an optical shutter back-end unit.

9. A cold wallet server according to claim 7, characterized in that: The external network interface machine is connected to the external network firewall before connecting to the external network.

10. A cold wallet server according to claim 7, characterized in that: An internal network firewall is set up between the internal network interface and the cold wallet server.

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