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

# Keccak256 Implementations

> Comparison and selection guide for Keccak256 implementation options

<Card title="Try it Live" icon="play" href="https://playground.tevm.sh?example=crypto/keccak256.ts">
  Run Keccak256 examples in the interactive playground
</Card>

<Warning>
  **Future Plans:** This page is planned and under active development. Examples are placeholders and will be replaced with accurate, tested content.
</Warning>

# Keccak256 Implementation Guide

Voltaire provides two Keccak256 implementations optimized for different deployment scenarios. All share the same data-first API, enabling transparent algorithm swapping.

## Implementation Comparison

| Implementation      | Bundle Size          | Init Required | Platform Support             |
| ------------------- | -------------------- | ------------- | ---------------------------- |
| **WASM (Default)**  | Smaller than pure JS | Yes (async)   | All modern browsers/runtimes |
| **Pure TypeScript** | \~25KB (@noble)      | No            | Universal                    |

## When to Use Each Implementation

### WASM (Default)

**Use when:**

* Default choice for most applications
* Better performance than pure JavaScript
* Smaller bundle size than pure JavaScript alternatives

**Characteristics:**

```typescript theme={null}
import { Keccak256 } from '@tevm/voltaire/Keccak256';

const hash = Keccak256.hash(data);
// WASM implementation
```

* **Pros:** Better performance, smaller bundle
* **Cons:** Async init required
* **Bundle:** Smaller than @noble/hashes

### Pure TypeScript

**Use when:**

* Need to avoid WASM dependency
* Debugging or development scenarios
* Specific compatibility requirements

**Characteristics:**

```typescript theme={null}
import { Keccak256Ts } from '@tevm/voltaire/Keccak256/native';

// No initialization needed
const hash = Keccak256Ts.hash(data);
```

* **Pros:** Zero setup, runs everywhere, synchronous, no WASM
* **Cons:** Larger bundle than WASM
* **Bundle:** \~25KB (minified @noble/hashes)

## Platform Compatibility

### Browsers

* ✅ WASM (Default)
* ✅ Pure TypeScript

### Node.js / Bun / Deno

* ✅ WASM (Default)
* ✅ Pure TypeScript

### Edge Runtimes (Cloudflare, Vercel)

* ✅ WASM (Default)
* ✅ Pure TypeScript

## Initialization Requirements

### Synchronous (No Init)

Pure TypeScript implementation is ready immediately:

```typescript theme={null}
import { Keccak256Ts } from '@tevm/voltaire/Keccak256/native';

// Use immediately
const hash = Keccak256Ts.hash(data);
```

### Asynchronous (Init Required)

WASM variant requires async initialization:

```typescript theme={null}
import { Keccak256Wasm } from '@tevm/voltaire/Keccak256/wasm';

// Initialize once at startup
await Keccak256Wasm.init();

// Check if ready
if (Keccak256Wasm.isReady()) {
  const hash = Keccak256Wasm.hash(data);
}
```

**Important:** WASM init is idempotent - calling `init()` multiple times is safe.

## Bundle Size

### WASM (Default)

Smaller than pure JavaScript alternatives:

* Zig stdlib Keccak-256 implementation
* Part of main WASM bundle
* Smaller than @noble/hashes when considering full implementation

### Pure TypeScript

Includes @noble/hashes dependencies:

* Full @noble/hashes/sha3 module (\~25KB)
* Tree-shakeable (only Keccak-256 if unused)

## Selection Decision Tree

```
Need Keccak256?
├─ Need to avoid WASM dependency?
│  ├─ Yes → Pure TypeScript
│  └─ No → WASM (Default)
└─ Async init acceptable?
   ├─ Yes → WASM (better performance, smaller bundle)
   └─ No → Pure TypeScript
```

## Migration Examples

### From Pure TypeScript to WASM

```typescript theme={null}
// Before
import { Keccak256Ts } from '@tevm/voltaire/Keccak256/native';
const hash = Keccak256Ts.hash(data);

// After (minimal change)
import { Keccak256Wasm } from '@tevm/voltaire/Keccak256/wasm';
await Keccak256Wasm.init(); // Add at startup
const hash = Keccak256Wasm.hash(data); // Same API
```

### Conditional Selection

```typescript theme={null}
// Select implementation based on requirements
const Keccak256Impl = await (async () => {
  if (typeof WebAssembly !== 'undefined') {
    // WASM available - use default
    const { Keccak256Wasm } = await import('@tevm/voltaire/Keccak256/wasm');
    await Keccak256Wasm.init();
    return { Keccak256: Keccak256Wasm };
  }

  // Fallback to pure TypeScript
  const { Keccak256Ts } = await import('@tevm/voltaire/Keccak256/native');
  return { Keccak256: Keccak256Ts };
})();

// Use selected implementation
const hash = Keccak256Impl.Keccak256.hash(data);
```

## Related

* [Keccak256 API Reference](/crypto/keccak256) - Main documentation
* [Cryptography Overview](/crypto) - All crypto functions
* [WASM Guide](/concepts/wasm) - WASM deployment details
* [Performance Benchmarks](/benchmarks) - Detailed benchmark results