Merge pull request #117 from BitGo/WP5535/demo-script-dinamo

feat(kms): demo script for dinamo interface

Author: pranavjain97

demo-kms-script/dinamo-interface.md

@@ -0,0 +1,254 @@
+# Dinamo HSM KMS Implementation Documentation
+
+## ⚠️ Security Recommendation
+
+**For production KMS implementations, consider implementing the KMS-API in a C++ like language, or use typed arrays like Uint8Array for all sensitive data because JavaScript does not support secure memory management.**
+
+**Recommended Alternatives:**
+- **C++/Rust**: Languages with explicit memory management and secure allocation
+- **Node.js Typed Arrays**: Use `Uint8Array` for sensitive data with explicit zeroing
+- **Native Addons**: Implement cryptographic operations in native C++ modules
+- **Hardware Security**: Use HSM-backed secure memory when available
+
+This document provides a reference implementation for integrating the 4 KMS API's with Dinamo HSM, covering the complete request-response flow from API handlers to HSM operations.
+
+## Demo Scripts
+
+- **`real-dinamo-flow.ts`** - Complete handler-to-provider-to-HSM-to-database flow demonstration
+- **`dinamo-provider-implementation.ts`** - Core provider implementation patterns and methods
+- **`DINAMO_HSM_IMPLEMENTATION.md`** - Original deep-dive documentation (legacy)
+
+## Quick Overview
+
+The KMS API provides secure key management through four main endpoints that integrate with Dinamo HSM:
+
+- `POST /key` - Store private keys using envelope encryption
+- `GET /key/{pub}` - Retrieve private keys using envelope decryption  
+- `POST /generateDataKey` - Generate AES keys in HSM for encryption
+- `POST /decryptDataKey` - Decrypt data keys using root keys
+
+## Architecture Flow
+
+```
+API Request → Handler → KMS Provider → Dinamo HSM → Database → Response
+```
+
+### Handler-to-Provider Mapping
+
+| API Endpoint | Handler File | Provider Method | HSM Operations |
+|--------------|--------------|-----------------|----------------|
+| `POST /key` | `storePrivateKey.ts` | `postKey()` | Create AES key, export, encrypt |
+| `GET /key/{pub}` | `getPrivateKey.ts` | `getKey()` | Decrypt data key locally |
+| `POST /generateDataKey` | `generateDataKey.ts` | `generateDataKey()` | Create/export AES key |
+| `POST /decryptDataKey` | `decryptDataKey.ts` | `decryptDataKey()` | Local SJCL decryption |
+
+## Envelope Encryption Pattern (Recommended) 
+
+### Layer 1: Root Keys (HSM)
+- **Algorithm**: RSA-2048 asymmetric keys
+- **Storage**: Dinamo HSM hardware (permanent)
+- **Purpose**: Encrypt/decrypt data keys
+- **Security**: Never exported from HSM
+
+### Layer 2: Data Keys (Generated in HSM, Used Locally)
+- **Algorithm**: AES-256 symmetric keys
+- **Generation**: Dinamo HSM (temporary keys)
+- **Export**: Raw key material exported as Buffer
+- **Encryption**: Encrypted with root key using SJCL
+- **Storage**: Database (encrypted), Memory (plaintext, temporary)
+
+### Layer 3: Private Keys (Application Data)
+- **Encryption**: AES-256-CCM using SJCL
+- **Key**: Data key plaintext (from Layer 2)
+- **Storage**: Database (encrypted only)
+
+## Implementation Details
+
+### Connection Management Pattern
+
+```typescript
+private async withClient<T>(fn: (client) => Promise<T>): Promise<T> {
+  const conn = await hsm.connect({
+    host: process.env.DINAMO_HOST || "",
+    authUsernamePassword: {
+      username: process.env.DINAMO_USERNAME || "",
+      password: process.env.DINAMO_PASSWORD || "",
+    },
+  });
+
+  try {
+    return await fn(conn);
+  } finally {
+    try {
+      await conn.disconnect();
+    } catch (e) {
+      logger.warn("Failed to disconnect from Dinamo HSM", e);
+    }
+  }
+}
+```
+
+**Why Connection Management is Critical:**
+- **Prevents Resource Leaks**: Ensures HSM connections are properly closed to avoid dangling connections
+- **HSM Connection Limits**: Hardware security modules have limited concurrent connection pools
+- **Network Stability**: Prevents socket exhaustion and connection timeouts
+- **Security Best Practice**: Minimizes attack surface by closing connections immediately after use
+
+### Root Key Creation
+
+```typescript
+async createRootKey(): Promise<{ rootKey: string }> {
+  const keyName = getRandomHash(32);
+  
+  return await this.withClient(async (client) => {
+    const created = await client.key.create(
+      keyName,                                    // Unique key identifier
+      hsm.enums.RSA_ASYMMETRIC_KEYS.ALG_RSA_2048, // 2048-bit RSA
+      true,                                       // Exportable for public key ops
+      false                                       // Permanent storage
+    );
+    
+    if (!created) {
+      throw { message: 'Failed to create symmetric key in HSM', code: 500 };
+    }
+    
+    return { rootKey: keyName };
+  });
+}
+```
+
+**HSM Operations:**
+- **Key Naming**: 32-character random hash for uniqueness
+- **Algorithm**: RSA-2048 for asymmetric operations
+- **Exportable**: Set to true to allow public key export
+- **Permanent**: Root keys stored permanently in HSM
+- **Error Handling**: Structured errors with HTTP codes
+
+### Data Key Generation Process
+
+```typescript
+async generateDataKey(rootKey: string, keySpec: DataKeyTypeType): Promise<GenerateDataKeyKmsRes> {
+  return await this.withClient(async (client) => {  // Connection auto-managed to prevent dangling connections
+    // 1. Create temporary AES key in HSM
+    const dataKeyName = getRandomHash(32);
+    const created = await client.key.create(
+      dataKeyName,
+      hsm.enums.SYMMETRICAL_KEYS.ALG_AES_256,  // 256-bit AES
+      true,                                     // Exportable
+      true                                      // Temporary (auto-deleted)
+    );
+
+    // 2. Export plaintext key material
+    const exportedKey = await client.key.exportSymmetric(dataKeyName);
+    const plaintextKey = exportedKey.toString('base64');
+    
+    // **CRITICAL SECURITY NOTE**: The plaintextKey contains raw cryptographic material
+    // and MUST be wiped from memory immediately after encryption operations.
+    // In production, use secure memory allocation and explicit zeroing.
+
+    // 3. Encrypt with root key (envelope encryption)
+    return {
+      encryptedKey: encrypt(rootKey, plaintextKey),  // SJCL encryption
+      plaintextKey: plaintextKey,                    // For immediate use - WIPE AFTER USE
+    };
+  });
+}
+```
+
+**Process Flow:**
+1. **Temporary Key Creation**: AES-256 symmetric key in HSM
+2. **Key Export**: Raw key material extracted as Buffer
+3. **Format Conversion**: Buffer → base64 string
+4. **Envelope Encryption**: Encrypt plaintext with root key
+5. **Automatic Cleanup**: HSM deletes temporary key
+6. **⚠️ MEMORY SECURITY**: Plaintext key must be wiped from memory after use
+
+
+**Security Considerations:**
+- **Immediate Use**: Plaintext keys should be used immediately after generation
+- **Memory Overwriting**: Overwrite memory locations with random data before deallocation
+- **Garbage Collection**: Force GC to clear memory pages containing sensitive data
+- **Process Isolation**: Consider using separate processes for key operations
+- **Hardware Security**: Use HSM-backed secure memory when available
+
+### Private Key Storage (POST /key)
+
+```typescript
+async postKey(rootKey: string, prv: string): Promise<PostKeyKmsRes> {
+  // 1. Generate fresh data key for this private key
+  const dataKey = await this.generateDataKey(rootKey, 'AES-256');
+  
+  let encryptedPrv: string;
+  try {
+    // 2. Encrypt private key with data key (use immediately)
+    encryptedPrv = encrypt(dataKey.plaintextKey, prv);
+  } finally {
+    // **CRITICAL**: Wipe plaintext data key from memory immediately after use
+    // Production code should implement secure memory wiping here
+  }
+
+  return {
+    encryptedPrv,                              // Encrypted private key
+    rootKeyId: rootKey,                        // Root key reference
+    metadata: {
+      encryptedDataKey: dataKey.encryptedKey,  // Encrypted data key
+    },
+  };
+}
+```
+
+**Memory Security Notes:**
+- **Immediate Encryption**: Use plaintext data key immediately for encryption
+- **Secure Disposal**: Wipe plaintext key from memory after single use
+- **No Persistence**: Never store plaintext data keys in variables or logs
+- **Error Handling**: Ensure memory wiping occurs even if encryption fails
+
+## Database Schema
+
+### private_keys Table
+
+```sql
+CREATE TABLE private_keys (
+  id INTEGER PRIMARY KEY AUTOINCREMENT,
+  pub TEXT NOT NULL,                    -- Public key (identifier)
+  source TEXT NOT NULL,                 -- 'user' or 'backup'
+  encryptedPrv TEXT NOT NULL,           -- Private key encrypted with data key
+  encryptedDataKey TEXT NOT NULL,       -- Data key encrypted with root key
+  provider TEXT NOT NULL,               -- 'dinamo'
+  rootKey TEXT NOT NULL,                -- Root key name in HSM
+  coin TEXT NOT NULL,                   -- Cryptocurrency type
+  type TEXT NOT NULL,                   -- Key type (e.g., 'tss')
+  created_at DATETIME DEFAULT CURRENT_TIMESTAMP
+);
+```
+
+**Storage Pattern:**
+- **encryptedPrv**: SJCL AES-256-CCM encrypted private key
+- **encryptedDataKey**: Root-key-encrypted data key
+- **rootKey**: Reference to HSM root key name
+- **No plaintext**: All sensitive data encrypted
+
+## SJCL Encryption Details
+
+### Configuration
+- **Algorithm**: AES-256-CCM
+- **Iterations**: 10,000 (PBKDF2)
+- **Key Size**: 256 bits
+- **Tag Size**: 128 bits
+- **Mode**: CCM (Counter with CBC-MAC)
+
+### Example SJCL Output
+```json
+{
+  "iv": "a1b2c3d4e5f6...",
+  "v": 1,
+  "iter": 10000,
+  "ks": 256,
+  "ts": 128,
+  "mode": "ccm",
+  "adata": "",
+  "cipher": "aes",
+  "salt": "f6e5d4c3b2a1...",
+  "ct": "base64-encrypted-data"
+}
+```