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Overview

This guide covers wallet security features including private key management and key shares recovery with the Dynamic Swift SDK.

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Prerequisites

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Private Key Management

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Export Private Key

Export the wallet’s private key for backup or migration purposes: 
do {
    let privateKey = try await ethereumWallet.exportPrivateKey()
    print("✅ Private key exported successfully!")
    print("🔑 Private Key: \(privateKey)")

    // Note: Store securely and clear from memory after use
} catch {
    print("❌ Failed to export private key: \(error)")
}

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Key Shares Management

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Check Key Shares Availability

func checkKeySharesAvailability(client: DynamicClient, walletAddress: String) -> Bool {
    let keyShares = loadKeyShares(client: client, accountAddress: walletAddress)
    return keyShares != nil
}

// Usage
let hasKeyShares = checkKeySharesAvailability(
    client: dynamicClient,
    walletAddress: ethereumWallet.address.asString()
)

print("Key shares available: \(hasKeyShares)")

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Recover Key Shares

Recover encrypted backup for a wallet using key share IDs: 
private func recoverKeyshare(for credential: JwtVerifiedCredential) async {
    let walletId = credential.id

    guard let keyShareIds = getKeyShareIds(credential: credential) else {
        print("❌ No keyshare IDs found")
        return
    }

    do {
        let backup = try await recoverEncryptedBackupByWallet(
            client: dynamicClient,
            walletId: walletId,
            keyShareIds: keyShareIds,
            address: ethereumWallet.address.asString()
        )

        print("✅ Keyshare recovered successfully!")
        print("Backup: \(backup)")

    } catch {
        print("❌ Recovery failed: \(error)")
    }
}

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Security Best Practices

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1. Private Key Security

  • Never store private keys in plain text
  • Implement auto-clear for sensitive data
  • Use secure storage for backup data
  • Validate all user inputs before processing

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2. Memory Management

// Clear sensitive data from memory after use
privateKey = nil
keyShares = nil

// Use secure enclave when available
if SecureEnclave.isAvailable {
    // Store sensitive data in secure enclave
}

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3. Input Validation

// Always validate wallet addresses
func isValidEthereumAddress(_ address: String) -> Bool {
    let pattern = "^0x[a-fA-F0-9]{40}$"
    let regex = try! NSRegularExpression(pattern: pattern)
    let range = NSRange(location: 0, length: address.utf16.count)
    return regex.firstMatch(in: address, range: range) != nil
}

// Validate before processing
guard isValidEthereumAddress(walletAddress) else {
    print("❌ Invalid wallet address format")
    return
}

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4. Secure Storage

// Use Keychain for sensitive data storage
import Security

func storePrivateKeySecurely(_ privateKey: String, for walletAddress: String) {
    let query: [String: Any] = [
        kSecClass as String: kSecClassGenericPassword,
        kSecAttrAccount as String: walletAddress,
        kSecValueData as String: privateKey.data(using: .utf8)!,
        kSecAttrAccessible as String: kSecAttrAccessibleWhenUnlockedThisDeviceOnly
    ]

    SecItemAdd(query as CFDictionary, nil)
}

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Error Handling

do {
    let privateKey = try await ethereumWallet.exportPrivateKey()
} catch {
    if let nsError = error as NSError? {
        switch nsError.code {
        case 1001:
            print("Access denied - authentication required")
        case 1002:
            print("Private key not available")
        case 1003:
            print("Security validation failed")
        default:
            print("Security error: \(error)")
        }
    }
}

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Next Steps

After implementing wallet security, you can: