Auth

The @interchainjs/auth package provides foundational cryptographic capabilities for blockchain applications, offering wallet implementations and account management across different cryptographic algorithms including secp256k1 and ethSecp256k1. The package exposes consistent interfaces that allow signers to work with different algorithms without needing to know the underlying implementation details.

Core Interfaces

IWallet Interface

The IWallet interface provides the primary abstraction for managing cryptographic accounts:

• getAccounts(): Returns all accounts managed by this wallet
• getAccountByIndex(index): Gets a specific account by its index
• signByIndex(data, index): Signs arbitrary binary data using the specified account

IAccount Interface

The IAccount interface represents a single cryptographic account:

• address: The blockchain address for this account
• algo: The cryptographic algorithm used (e.g., 'secp256k1')
• getPublicKey(): Returns the public key for this account

IPrivateKey Interface

The IPrivateKey interface handles private key operations:

• toPublicKey(): Derives the corresponding public key
• sign(data): Signs binary data and returns a cryptographic signature
• fromMnemonic(): Static method to derive private keys from mnemonic phrases

Usage Patterns

Creating Wallets from Mnemonic

import { PrivateKey, BaseWallet } from '@interchainjs/auth';
import { HDPath } from '@interchainjs/types';
 
// Create private keys from mnemonic
const mnemonic = "your twelve word mnemonic phrase here";
const hdPaths = [HDPath.cosmos(0, 0, 0)]; // m/44'/118'/0'/0/0
const privateKeys = await PrivateKey.fromMnemonic(mnemonic, hdPaths);
 
// Create wallet with configuration
const wallet = new BaseWallet(privateKeys, config);

The auth layer is designed to be:

• Algorithm Agnostic: Works with different cryptographic algorithms (secp256k1, ed25519, etc.)
• Network Independent: Can be used across different blockchain networks
• Configurable: Supports different address derivation strategies and signature formats

See usage examples for integration with signers.

Wallet vs. OfflineSigner

IWallet Implementations

IWallet implementations provide direct access to private keys and full cryptographic control:

• Direct Key Access: Can sign arbitrary data and perform any cryptographic operation
• Multi-Account Management: Manages multiple accounts with different derivation paths
• Network Flexibility: Can be configured for different blockchain networks

OfflineSigner Interfaces

OfflineSigner interfaces provide secure signing without exposing private keys:

• External Wallet Integration: Designed for browser wallets like Keplr, Leap, or hardware wallets
• Limited Scope: Only supports specific document signing (Direct or Amino modes)
• Enhanced Security: Private keys remain in the external wallet environment

Integration with Signers

The auth layer integrates seamlessly with the signer layer:

IWallet Integration

import { DirectSigner } from '@interchainjs/cosmos';
import { Secp256k1HDWallet } from '@interchainjs/cosmos/wallets/secp256k1hd';
 
// Create wallet
const wallet = await Secp256k1HDWallet.fromMnemonic(mnemonic, derivations);
 
// Use with signer
const signer = new DirectSigner(wallet, config);

OfflineSigner Integration

import { DirectSigner } from '@interchainjs/cosmos';
 
// Get offline signer from external wallet (e.g., Keplr)
const offlineSigner = await window.keplr.getOfflineSigner(chainId);
 
// Use with signer
const signer = new DirectSigner(offlineSigner, config);

Flexibility Benefits

• Development: Use IWallet for full control during development and testing
• Production: Use OfflineSigner for secure integration with user wallets
• Compatibility: Both approaches work with the same signer interfaces

This design allows developers to choose the appropriate security model while maintaining consistent APIs across different usage scenarios.

See signer documentation for detailed integration examples.