Adding utility module (#16)

.gitmodules

@@ -1,3 +1,6 @@
 [submodule "Sources/secp256k1/secp256k1"]
 	path = Sources/secp256k1/secp256k1
 	url = https://github.com/bitcoin-core/secp256k1
+[submodule "Sources/swift-crypto/swift-crypto"]
+	path = Sources/swift-crypto/swift-crypto
+	url = https://github.com/apple/swift-crypto

Package.swift

@@ -10,7 +10,10 @@ let package = Package(
         // WARNING: These APIs should not be considered stable and may change at any time.
         .library(
             name: "secp256k1",
-            targets: ["secp256k1"]
+            targets: [
+                "secp256k1",
+                "secp256k1_utils"
+            ]
         )
     ],
     targets: [
@@ -42,9 +45,23 @@ let package = Package(
                 .define("ECMULT_GEN_PREC_BITS", to: "4", nil)
             ]
         ),
+        // Only include select utility extensions because most of Swift Crypto is not required
+        .target(
+            name: "secp256k1_utils",
+            path: "Sources/swift-crypto",
+            exclude: [
+                "swift-crypto/Sources",
+            ],
+            sources: [
+                "swift-crypto/Tests/CryptoTests/Utils/BytesUtil.swift"
+            ]
+        ),
         .testTarget(
             name: "secp256k1Tests",
-            dependencies: ["secp256k1"]
+            dependencies: [
+                "secp256k1",
+                "secp256k1_utils"
+            ]
         )
     ],
     swiftLanguageVersions: [.v5],

README.md

@@ -1,18 +1,18 @@
 # 🔐 secp256k1.swift [![Build Status](https://app.bitrise.io/app/ef44aebd8443b33b/status.svg?token=oDGzN3bMEwseXF_5MQUsTg&branch=main)](https://app.bitrise.io/app/ef44aebd8443b33b)
-Swift bindings library for ECDSA signatures and secret/public key operations using the [libsecp256k1](https://github.com/bitcoin-core/secp256k1) C library.
+Swift bindings library for ECDSA signatures and secret/public key operations using [libsecp256k1](https://github.com/bitcoin-core/secp256k1).
 
 # Objective
 This library aims to be a lightweight dependency for clients and wrapper libraries to include ECDSA functionality.
 
-This package targets the default git branch of secp256k1 and aims to stay up-to-date without using a mirrored repository.
+This package is set to the default git branch of secp256k1 and aims to stay up-to-date without using a mirrored repository. An extra module is available for convenience functionality.
 
 # Getting Started
 
 In your `Package.swift`:
 
 ```swift
 dependencies: [
-    .package(name: "secp256k1", url: "https://github.com/GigaBitcoin/secp256k1.swift.git", from: "0.0.1"),
+    .package(name: "secp256k1", url: "https://github.com/GigaBitcoin/secp256k1.swift.git", from: "0.0.11"),
 ]
 ```
 
@@ -22,26 +22,27 @@ Currently, this Swift package only provides a single product library built using
 
 ```swift
 import secp256k1
+import secp256k1_utils
 
 // Initialize context
 let context = secp256k1_context_create(UInt32(SECP256K1_CONTEXT_SIGN | SECP256K1_CONTEXT_VERIFY))!
 
 // Setup private and public key variables
-var pubkeyLen = 65
+var pubkeyLen = 33
 var cPubkey = secp256k1_pubkey()
 var pubkey = [UInt8](repeating: 0, count: pubkeyLen)
-let privkey: [UInt8] = [0,1,0,0,1,0,1,0,1,0,1,0,1,0,0,1,1,1,0,0,1,0,0,1,1,0,0,1,0,0,32,0]
+let privkey = try! Array(hexString: "14e4a74438858920d8a35fb2d88677580b6a2ee9be4e711ae34ec6b396d87b5c")
 
 // Verify the context and keys are setup correctly
 guard secp256k1_context_randomize(context, privkey) == 1,
     secp256k1_ec_pubkey_create(context, &cPubkey, privkey) == 1,
-    secp256k1_ec_pubkey_serialize(context, &pubkey, &pubkeyLen, &cPubkey, UInt32(SECP256K1_EC_UNCOMPRESSED)) == 1 else {
+    secp256k1_ec_pubkey_serialize(context, &pubkey, &pubkeyLen, &cPubkey, UInt32(SECP256K1_EC_COMPRESSED)) == 1 else {
     // Destory context after creation
     secp256k1_context_destroy(context)
     return
 }
 
-print(pubkey) //  [4,96,104, 212, 128, 165, 213, 207, 134, 132, 22, 247, 38, 114, 82, 108, 77, 43, 6, 56, ... ]
+print(pubkey.hexString) //  02734b3511150a60fc8cac329cd5ff804555728740f2f2e98bc4242135ef5d5e4e
 
 // Destory context after creation
 secp256k1_context_destroy(context)

Tests/secp256k1Tests/secp256k1Tests.swift

@@ -1,47 +1,68 @@
 import XCTest
 @testable import secp256k1
+@testable import secp256k1_utils
 
 final class secp256k1Tests: XCTestCase {
-    /// Basic Keypair test
-    func testKeypairCreation() {
+    /// Uncompressed Keypair test
+    func testUncompressedKeypairCreation() {
         // Initialize context
         let context = secp256k1_context_create(UInt32(SECP256K1_CONTEXT_SIGN | SECP256K1_CONTEXT_VERIFY))!
 
         // Destory context after execution
-        defer {
-            secp256k1_context_destroy(context)
-        }
+        defer { secp256k1_context_destroy(context) }
 
         // Setup private and public key variables
         var pubkeyLen = 65
         var cPubkey = secp256k1_pubkey()
-        var pubkey = [UInt8](repeating: 0, count: pubkeyLen)
-        let privkey: [UInt8] = [0,1,0,0,1,0,1,0,1,0,1,0,1,0,0,1,1,1,0,0,1,0,0,1,1,0,0,1,0,0,32,0]
+        var publicKey = [UInt8](repeating: 0, count: pubkeyLen)
+
+        let privateKey = try! Array(hexString: "14E4A74438858920D8A35FB2D88677580B6A2EE9BE4E711AE34EC6B396D87B5C".lowercased())
+
+        // Verify the context and keys are setup correctly
+        XCTAssertEqual(secp256k1_context_randomize(context, privateKey), 1)
+        XCTAssertEqual(secp256k1_ec_pubkey_create(context, &cPubkey, privateKey), 1)
+        XCTAssertEqual(secp256k1_ec_pubkey_serialize(context, &publicKey, &pubkeyLen, &cPubkey, UInt32(SECP256K1_EC_UNCOMPRESSED)), 1)
 
+        let hexString = """
+        04734B3511150A60FC8CAC329CD5FF804555728740F2F2E98BC4242135EF5D5E4E6C4918116B0866F50C46614F3015D8667FBFB058471D662A642B8EA2C9C78E8A
+        """
+
+        // Define the expected public key
+        let expectedPublicKey = try! Array(hexString: hexString.lowercased())
+
+        // Verify the generated public key matches the expected public key
+        XCTAssertEqual(expectedPublicKey, publicKey)
+    }
+
+    /// Compressed Keypair test
+    func testCompressedKeypairCreation() {
+        // Initialize context
+        let context = secp256k1_context_create(UInt32(SECP256K1_CONTEXT_SIGN | SECP256K1_CONTEXT_VERIFY))!
+
+        // Destory context after execution
+        defer { secp256k1_context_destroy(context) }
+
+        // Setup private and public key variables
+        var pubkeyLen = 33
+        var cPubkey = secp256k1_pubkey()
+        var publicKey = [UInt8](repeating: 0, count: pubkeyLen)
+
+        let privateKey = try! Array(hexString: "B035FCFC6ABF660856C5F3A6F9AC51FCA897BB4E76AD9ACA3EFD40DA6B9C864B".lowercased())
+
         // Verify the context and keys are setup correctly
-        XCTAssertEqual(secp256k1_context_randomize(context, privkey), 1)
-        XCTAssertEqual(secp256k1_ec_pubkey_create(context, &cPubkey, privkey), 1)
-        XCTAssertEqual(secp256k1_ec_pubkey_serialize(context, &pubkey, &pubkeyLen, &cPubkey, UInt32(SECP256K1_EC_UNCOMPRESSED)), 1)
+        XCTAssertEqual(secp256k1_context_randomize(context, privateKey), 1)
+        XCTAssertEqual(secp256k1_ec_pubkey_create(context, &cPubkey, privateKey), 1)
+        XCTAssertEqual(secp256k1_ec_pubkey_serialize(context, &publicKey, &pubkeyLen, &cPubkey, UInt32(SECP256K1_EC_COMPRESSED)), 1)
 
         // Define the expected public key
-        let expectedPublicKey: [UInt8] = [
-            4,96,104, 212, 128, 165, 213,
-            207, 134, 132, 22, 247, 38,
-            114, 82, 108, 77, 43, 6, 56,
-            80, 113, 12, 11, 119, 7, 240,
-            188, 73, 170, 44, 202, 33, 225,
-            30, 248, 53, 138, 34, 22, 100,
-            96, 31, 76, 64, 125, 71, 127,
-            62, 155, 108, 243, 17, 222, 97,
-            234, 75, 247, 187, 83, 151, 206,
-            27, 38, 228
-        ]
+        let expectedPublicKey = try! Array(hexString: "02EA724B70B48B61FB87E4310871A48C65BF38BF3FDFEFE73C2B90F8F32F9C1794".lowercased())
 
         // Verify the generated public key matches the expected public key
-        XCTAssertEqual(expectedPublicKey, pubkey)
+        XCTAssertEqual(expectedPublicKey, publicKey)
     }
 
     static var allTests = [
-        ("testKeypairCreation", testKeypairCreation),
+        ("testUncompressedKeypairCreation", testUncompressedKeypairCreation),
+        ("testCompressedKeypairCreation", testCompressedKeypairCreation),
     ]
 }