> ## Documentation Index
> Fetch the complete documentation index at: https://docs.mpcvault.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Key Derivation

> MPCVault's patented hardened key derivation for MPC wallets.

## Hardened Derivation

MPCVault is the only MPC provider with patented hardened hierarchical derivation. In the non-MPC world, all wallets use hardened derivation - MPCVault brings this security standard to MPC.

<img src="https://mintcdn.com/mpcvault-47/kq3LAw0DIlTzrGcF/images/hd.jpg?fit=max&auto=format&n=kq3LAw0DIlTzrGcF&q=85&s=631be65dfd570967500d001242af6779" alt="Hardened Derivation" width="5760" height="3240" data-path="images/hd.jpg" />

## Why Hardened Derivation Matters

Without hardened keys:

| Risk                  | Impact                                              |
| --------------------- | --------------------------------------------------- |
| Former team members   | Can track your newly added assets                   |
| Compromised child key | Exposes master keys and assets on other blockchains |
| Cross-chain attacks   | Signature reuse across different chains             |

With MPCVault's hardened derivation, each address has an isolated derived key. Compromise of one key does not affect others.

## How It Works

For each new address you create:

1. A new derived key is generated from your master key
2. The derivation uses hardened paths that prevent key leakage
3. Each blockchain and address is cryptographically isolated

<img src="https://mintcdn.com/mpcvault-47/kq3LAw0DIlTzrGcF/images/key-derivation.jpg?fit=max&auto=format&n=kq3LAw0DIlTzrGcF&q=85&s=798b1489051160eb940713a046561f7b" alt="Key Derivation Process" width="1440" height="810" data-path="images/key-derivation.jpg" />

## Granular Permissions

The hierarchical derivation tree enables precise permission control:

* Grant access to specific vaults only
* Limit users to certain blockchains
* Follow the principle of least privilege

Allocate minimum necessary permissions to users for managing vaults.

***

## Derivation Paths & Networks

MPCVault uses a structured derivation path format to generate unique keys for each vault, network, and address.

### Path Format

```
[prefix, vault_index, coin_type, account, change, address_index]
```

| Position | Name            | Description                             |
| -------- | --------------- | --------------------------------------- |
| 0        | `prefix`        | Always `9` (MPCVault identifier)        |
| 1        | `vault_index`   | Vault number starting from 0            |
| 2        | `coin_type`     | Blockchain identifier (see table below) |
| 3        | `account`       | Account index (typically 0)             |
| 4        | `change`        | Change index (typically 0)              |
| 5        | `address_index` | Address index (0, 1, 2, ...)            |

### Hardening Rules

Different networks use different hardening for the last two path positions:

| Network        | Last Two Positions        | Example                    |
| -------------- | ------------------------- | -------------------------- |
| **Bitcoin**    | Non-hardened (`N0`, `N1`) | `[9,0,2147483648,0,N0,N0]` |
| **All others** | Hardened (0, 1, 2...)     | `[9,0,2147483708,0,0,0]`   |

<Info>
  Non-hardened derivation (marked with `N`) allows public key derivation without the private key, which is required for Bitcoin's address discovery mechanism.
</Info>

### Supported Networks

| Network              | Coin Type  | Key Type | Curve     | Example Path               |
| -------------------- | ---------- | -------- | --------- | -------------------------- |
| EVM (Ethereum, etc.) | 2147483708 | ECDSA    | secp256k1 | `[9,0,2147483708,0,0,0]`   |
| Bitcoin              | 2147483648 | ECDSA    | secp256k1 | `[9,0,2147483648,0,N0,N0]` |
| Tron                 | 2147483843 | ECDSA    | secp256k1 | `[9,0,2147483843,0,0,0]`   |
| Aptos                | 2147484285 | EdDSA    | Ed25519   | `[9,0,2147484285,0,0,0]`   |
| Solana               | 2147484149 | EdDSA    | Ed25519   | `[9,0,2147484149,0,0,0]`   |
| Sui                  | 2147484432 | EdDSA    | Ed25519   | `[9,0,2147484432,0,0,0]`   |
| TON                  | 2147484355 | EdDSA    | Ed25519   | `[9,0,2147484355,0,0,0]`   |

<Note>
  Coin types follow the [SLIP-0044](https://github.com/satoshilabs/slips/blob/master/slip-0044.md) standard with the hardened bit (0x80000000) applied.
</Note>

### Key Types

MPCVault supports two cryptographic signature schemes:

| Key Type  | Curve     | Used By                             |
| --------- | --------- | ----------------------------------- |
| **ECDSA** | secp256k1 | EVM chains, Bitcoin, Tron, Litecoin |
| **EdDSA** | Ed25519   | Aptos, Solana, Sui, TON             |

### Address Generation

Each network derives addresses from public keys using different algorithms:

| Network | Hash Algorithm             | Address Format            | Example         |
| ------- | -------------------------- | ------------------------- | --------------- |
| EVM     | Keccak-256 (last 20 bytes) | `0x` + 40 hex chars       | `0x1234...abcd` |
| Bitcoin | SHA-256 + RIPEMD-160       | SegWit P2SH (Base58Check) | `3J98t1...`     |
| Tron    | Keccak-256 + Base58Check   | `T` prefix                | `TJRyWw...`     |
| Aptos   | SHA3-256                   | `0x` + 64 hex chars       | `0x1234...`     |
| Solana  | Direct public key          | Base58                    | `7EcDhS...`     |
| Sui     | BLAKE2b                    | `0x` + 64 hex chars       | `0x1234...`     |
| TON     | SHA-256                    | Base64 or raw             | `EQDk2V...`     |

### Deriving Multiple Addresses

To create multiple addresses within the same vault and network, increment the `address_index`:

```
Vault 0, EVM, Address 0: [9,0,2147483708,0,0,0]
Vault 0, EVM, Address 1: [9,0,2147483708,0,0,1]
Vault 0, EVM, Address 2: [9,0,2147483708,0,0,2]
```

Each address has a completely independent derived key due to hardened derivation.