> ## 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.

# Signature (Swift)

> ECDSA secp256k1 signatures (r, s, v)

# Signature

ECDSA signatures over secp256k1 with recovery and normalization.

## Quick Start

```swift theme={null}
import Voltaire

// Parse compact signature (64 or 65 bytes)
var r = [UInt8](repeating: 0, count: 31) + [0x01]
var s = [UInt8](repeating: 0, count: 31) + [0x02]
let sig = try Signature(compact: r + s)

// Normalize (low-s) and serialize
let normalized = sig.normalized()
let compact64 = normalized.serialize(includeV: false)

// Validate r/s are within curve order
XCTAssertTrue(normalized.isValid)

// Recover public key / address from message hash
let msg = Keccak256.hash("hello")
if normalized.v == 0 || normalized.v == 27 || normalized.v == 28 {
  let pub = try normalized.recoverPublicKey(messageHash: msg)
  let addr = try normalized.recoverAddress(messageHash: msg)
  print(pub.uncompressed.count, addr.hex)
}
```