StarkEx V4.5
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Introduction
High-Level Overview
Deployments
Integrating your application with StarkEx
Release notes
New features and updates
API updates
StarkEx Deep Dive
Off-chain state
StarkEx, Cairo, and SHARP
Flow Description
StarkEx Contracts
StarkEx Specific Concepts
Becoming an Oracle Provider for StarkEx
Message Encodings
Data Availability Modes
Batch Flash Loans
DeFi Pooling
Crypto
STARK Curve
Pedersen Hash Function
Key Derivation
Wallets
Important Links
StarkEx V4.5 REST API
StarkEx V4.0 Cairo code
StarkEx V4.0 Contract Change Log
StarkEx SDK
StarkEx Crypto SDK
StarkEx V4.0 Smart Contracts - Spot trading
StarkEx Perpetual V2.0 REST API
StarkEx Perpetual V2.0 Smart Contract
Architecture
Solution Architecture
StarkEx Applications
StarkEx Smart Contracts Architecture
StarkEx Back End Architecture
StarkEx Partner Integration
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Key Derivation
StarkWare recommends two methods for starkKey derivation, depending on the type of the wallet:
  • BIP32 compatible wallets, e.g. Ledger.
  • Non BIP32 wallets.

BIP32 Compatible Wallets

BIP32 compatible wallets should implement EIP-2645. This EIP describes a path, called starkPath and a key derivation algorithm that uses this path to derive the starkPrivateKey.
The starkPath consists of four passed parameters and two internal parameters as described below, and has the following structure: m/purpose'/layer'/application'/ethAddress1'/ethAddress2'/index

Passed Parameters

  • purpose - 2645
  • layer - Differentiate between technologies, defined as sha256(layer) & ((1 << 31) - 1)). In the context of starkex, the value would be 579218131 as described in EIP-2645.
  • application - Differentiate between applications, defined as sha256(application_name) & ((1 << 31) - 1)).
  • index - Allows multiple keys per Ethereum address.

Internal Parameters

  • ethAddress1 - 31 LSB of the user Ethereum address (i.e. ethAddress & ((1 << 31) - 1))
  • ethAddress2 - 31 following LSB of the user Ethereum address (i.e. (ethAddress >> 31) & ((1 << 31) - 1))
Note that BIP32 compatible wallets are expected to be stateful of their own Ethereum address.

Non-BIP32 Wallets

The derivation of starkKey proceeds in 2 steps:
  1. 1.
    The user signs a message, using his Ethereum signature (e.g. using MetaMask). It is recommended to use EIP712 in order to provide transparency to the user when they are signing the message. An important recommendation is to add a warning inside the message that the user should only sign this message if it was sent from a specific domain (as in Image 1).
  2. 2.
    The signature (r,s,v) is used as an input to the grinding algorithm that outputs the starkPrivateKey . You can use StarkEx crypto SDK to derive the key. Call the function getPrivateKeyFromEthSignature to generate the private key from the signature and then privateToStarkKey to comput the StarkKey.
Image 1 - A MetaMask pop-up when a user is requested to sign using the Ethereum key in order to generate a private STARK key. The message contains a warning to sign only messages from a specific domain
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Pedersen Hash Function
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Wallets
Last modified 2d ago
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Outline
BIP32 Compatible Wallets
Passed Parameters
Internal Parameters
Non-BIP32 Wallets