MEMBER_API.md

Member API Documentation

Overview

The Member class provides cryptographic identity management with BIP39 mnemonic support for BrightChain. Members can sign data, verify signatures, and be created from mnemonics for easy backup and recovery.

Features

• BIP39 Mnemonic Generation: Generate 12-word mnemonics for key backup
• Mnemonic Validation: Validate BIP39 mnemonics
• Deterministic Key Derivation: Recreate same keys from same mnemonic
• Multiple Member Types: Admin, System, User, Anonymous
• ECDSA Signing: Sign and verify data using secp256k1
• Public-Only Members: Create members without private keys for verification

Creating Members

Generate New Member with Mnemonic

// Generate a 12-word mnemonic
std::string mnemonic = Member::generateMnemonic();

// Create member from mnemonic
auto member = Member::fromMnemonic(
    mnemonic,
    MemberType::User,
    "Alice",
    "alice@example.com"
);

Recreate Member from Existing Mnemonic (Login)

// User provides their mnemonic
std::string userMnemonic = "garment opinion monitor gold never catalog pond sunset spell penalty wrist few";

// Validate mnemonic first
if (!Member::validateMnemonic(userMnemonic)) {
    throw std::runtime_error("Invalid mnemonic");
}

// Recreate member - will have same keys and ID
auto member = Member::fromMnemonic(
    userMnemonic,
    MemberType::User,
    "Alice",
    "alice@example.com"
);

Mnemonic Operations

Generate Mnemonic

std::string mnemonic = Member::generateMnemonic();
// Returns: 12-word BIP39 mnemonic (128 bits of entropy)

Validate Mnemonic

bool isValid = Member::validateMnemonic(mnemonic);

Usage Examples

Complete Registration Flow

// 1. Generate new member with mnemonic
std::string mnemonic = Member::generateMnemonic();
auto member = Member::fromMnemonic(
    mnemonic,
    MemberType::User,
    "Alice",
    "alice@example.com"
);

// 2. Display mnemonic to user for backup
std::cout << "IMPORTANT: Save this mnemonic phrase:\n";
std::cout << mnemonic << "\n";

// 3. Store member ID and public key
std::string memberId = member.idHex();

Complete Login Flow

// 1. User provides mnemonic
std::string userMnemonic = getUserInput();

// 2. Validate mnemonic
if (!Member::validateMnemonic(userMnemonic)) {
    std::cerr << "Invalid mnemonic phrase\n";
    return;
}

// 3. Recreate member
auto member = Member::fromMnemonic(
    userMnemonic,
    MemberType::User,
    "Alice",
    "alice@example.com"
);

std::cout << "Login successful!\n";