Hardware Wallet Key Derivation for Offline Transaction Signing
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Solution Overview
Problem
Existing cryptocurrency wallets fail to securely manage and protect private keys from theft and hacking, especially in online environments, and require large storage capacity for multiple cryptocurrency keys.
Innovation Solution
A hardware wallet that securely generates private keys using a root seed and coin seed, enabling cryptographic signing without persistently storing keys, and supports multiple cryptocurrencies through hierarchical deterministic key generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If private keys are stored online or in software-connected devices, then ease of operation is improved, but security is worsened due to theft and hacking risks
Solution Approach 1:
The system separates the key storage function from the operation execution function. The secure element stores private keys in isolation, while the host device performs transaction operations. This segmentation allows online operation convenience while maintaining offline security isolation.
Solution Approach 2:
A secure element acts as an intermediary between the user and the transaction system. It receives transaction requests from the host device, performs cryptographic signing internally without exposing private keys, and returns signed transactions. This intermediary protects keys from direct exposure while enabling operational convenience.
2Adaptability or versatility
If multiple cryptocurrency keys are stored in hardware wallet, then adaptability is improved, but storage capacity requirements increase
Solution Approach 1:
The secure element is designed with universal cryptographic functionality that can handle multiple cryptocurrency types. Rather than storing separate key pairs for each cryptocurrency, the system uses a single secure element that can perform cryptographic operations for different currencies, reducing storage requirements while maintaining multi-currency adaptability.
Solution Approach 2:
The system changes the parameter of key generation from storing multiple complete key pairs to storing a single master secret and deriving multiple keys through cryptographic operations. This parameter change reduces storage capacity requirements while maintaining the ability to support multiple cryptocurrencies through hierarchical deterministic key derivation.
3Reliability
If private keys are generated and stored in the hardware wallet, then security is improved, but device complexity increases
Solution Approach 1:
The key generation and storage functionality is extracted into a separate secure element component, isolated from the main host device. This extraction places security-critical operations in a dedicated, hardened environment while keeping the overall system architecture modular and manageable, reducing complexity in the main device while maintaining high security.
Data Source
AI summary
A method and hardware wallet to securely signing a transaction. This includes the hardware wallet receiving, from a host application of a host device, an unsigned transaction and a coin seed associated with a cryptocurrency coin of the unsigned transaction. The hardware wallet generates a private key based on: a root seed stored in the storage medium of the hardware wallet; and the received coin seed. The hardware wallet cryptographically signs the unsigned transaction with the generated private key to generate a signed transaction and sends the signed transaction to the host device.