jb55/secp256k1.swift

ECDSA

import secp256k1

//  Private key
let privateBytes = try! "14E4A74438858920D8A35FB2D88677580B6A2EE9BE4E711AE34EC6B396D87B5C".bytes
let privateKey = try! secp256k1.Signing.PrivateKey(rawRepresentation: privateBytes)

//  Public key
print(String(bytes: privateKey.publicKey.rawRepresentation))

// ECDSA
let messageData = "We're all Satoshi.".data(using: .utf8)!
let signature = try! privateKey.ecdsa.signature(for: messageData)

//  DER signature
print(try! signature.derRepresentation.base64EncodedString())

Schnorr

let privateBytes = try! "C90FDAA22168C234C4C6628B80DC1CD129024E088A67CC74020BBEA63B14E5C9".bytes
let privateKey = try! secp256k1.Signing.PrivateKey(rawRepresentation: privateBytes)

// Extra params for custom signing
var auxRand = try! "C87AA53824B4D7AE2EB035A2B5BBBCCC080E76CDC6D1692C4B0B62D798E6D906".bytes
var messageDigest = try! "7E2D58D8B3BCDF1ABADEC7829054F90DDA9805AAB56C77333024B9D0A508B75C".bytes

// API allows for signing variable length messages
let signature = try! privateKey.schnorr.signature(message: &messageDigest, auxiliaryRand: &auxRand)

Tweak

let privateBytes = try! "C90FDAA22168C234C4C6628B80DC1CD129024E088A67CC74020BBEA63B14E5C9".bytes
let privateKey = try! secp256k1.Signing.PrivateKey(rawRepresentation: privateBytes)

// Adding a tweak to the private key and public key
let tweak = try! "5f0da318c6e02f653a789950e55756ade9f194e1ec228d7f368de1bd821322b6".bytes
let tweakedPrivateKey = try! privateKey.tweak(tweak)
let tweakedPublicKeyKey = try! privateKey.publicKey.tweak(tweak)

Elliptic Curve Diffie Hellman

let privateKey = try! secp256k1.KeyAgreement.PrivateKey()
let publicKey = try! secp256k1.KeyAgreement.PrivateKey().publicKey

// Create a shared secret with a private key from only a public key
let sharedSecret = try! privateKey.sharedSecretFromKeyAgreement(with: publicKey)

Silent Payments

let privateSign1 = try! secp256k1.Signing.PrivateKey()
let privateSign2 = try! secp256k1.Signing.PrivateKey()

let privateKey1 = try! secp256k1.KeyAgreement.PrivateKey(rawRepresentation: privateSign1.rawRepresentation)
let privateKey2 = try! secp256k1.KeyAgreement.PrivateKey(rawRepresentation: privateSign2.rawRepresentation)

let sharedSecret1 = try! privateKey1.sharedSecretFromKeyAgreement(with: privateKey2.publicKey)
let sharedSecret2 = try! privateKey2.sharedSecretFromKeyAgreement(with: privateKey1.publicKey)

let sharedSecretSign1 = try! secp256k1.Signing.PrivateKey(rawRepresentation: sharedSecret1.bytes)
let sharedSecretSign2 = try! secp256k1.Signing.PrivateKey(rawRepresentation: sharedSecret2.bytes)

// Payable Silent Payment public key
let xonlyTweak2 = try! sharedSecretSign2.publicKey.xonly.add(privateSign1.publicKey.xonly.bytes)

// Spendable Silent Payment private key
let privateTweak1 = try! sharedSecretSign1.add(xonly: privateSign1.publicKey.xonly.bytes)

Getting Started

This repository primarily uses Swift package manager as its build tool, so we recommend using that as well. If you want to depend on secp256k1.swift in your own project, simply add it as a dependencies' clause in your Package.swift:

.package(url: "https://github.com/GigaBitcoin/secp256k1.swift.git", .upToNextMajor(from: "0.6.0"))

Try in a playground using the SPI Playgrounds app or 🏟 Arena

arena GigaBitcoin/secp256k1.swift

Danger

These APIs should not be considered stable and may change at any time, libsecp256k1 is still experimental and has not been formally released.

Package Metadata

Repository: jb55/secp256k1.swift

Default branch: main

README: README.md