Add key init from hex string. Better README usage examples.

README.md

@@ -24,7 +24,35 @@ end
 
 ## Usage
 
-Please view [TariCryptoTests.swift](TariCryptoTests/TariCryptoTests.swift) for usage examples.
+Sample program that illustrates message signing and verification:
+
+```swift
+import TariCrypto
+
+// create a key pair from hex string representations, and sign & verify
+let keyPairFromHex = TariKeyPair(
+    privateKey: TariKey(hexString: "A35F68A5054C9721874CDE2553B80F98338952783C6E1687A2E8454B0D5BA200")!,
+    publicKey: TariKey(hexString: "50C5624924CE9B806FE40A94CA20B029DB6AC6DA098B3E48B89CE2695B265E71")!
+)
+let message = "A random message."
+let signedMessage = try keyPairFromHex.privateKey.signMessage(message: message)
+var isVerified = try keyPairFromHex.publicKey.verifySignature(signedMessage: signedMessage)
+print("Is first message verified? \(isVerified)")
+
+// or, do the same with a random key pair, and sign & verify
+let randomKeyPair = TariKeyPair.generateRandom()
+let anotherMessage = "Another random message."
+let anotherSignedMessage = try randomKeyPair.privateKey.signMessage(message: anotherMessage)
+isVerified = try randomKeyPair.publicKey.verifySignature(signedMessage: anotherSignedMessage)
+print("Is second message verified? \(isVerified)")
+```
+
+Program output:
+
+```
+Is first message verified? true
+Is second message verified? true
+```
 
 ## Testing
 

TariCrypto.podspec

@@ -20,7 +20,7 @@ Please visit the [GitHub repository](https://github.com/tari-labs/tari-crypto-io
   spec.pod_target_xcconfig = { 'VALID_ARCHS' => 'arm64 x86_64', 'EXCLUDED_ARCHS[sdk=iphonesimulator*]' => 'arm64' }
   spec.user_target_xcconfig = { 'VALID_ARCHS' => 'arm64 x86_64', 'EXCLUDED_ARCHS[sdk=iphonesimulator*]' => 'arm64' }
 
-  spec.source = { :git => "https://github.com/tari-labs/tari-crypto-ios.git", :tag => "v#{spec.version}" }
+  spec.source = { :git => "https://github.com/tari-labs/tari-crypto-ios.git", :tag => "#{spec.version}" }
   spec.source_files = "TariCrypto/**/*.{h,swift}"
   spec.ios.vendored_library = 'TariCrypto/TariLib/libtari_crypto.a'
 

TariCrypto.xcodeproj/project.pbxproj

@@ -472,7 +472,7 @@
 					"$(PROJECT_DIR)/TariCrypto/TariLib",
 				);
 				MARKETING_VERSION = 0.9.0;
-				ONLY_ACTIVE_ARCH = NO;
+				ONLY_ACTIVE_ARCH = YES;
 				PRODUCT_BUNDLE_IDENTIFIER = com.tari.TariCrypto;
 				PRODUCT_NAME = "$(TARGET_NAME:c99extidentifier)";
 				SKIP_INSTALL = YES;

TariCrypto.xcodeproj/xcshareddata/xcschemes/TariCrypto.xcscheme

@@ -41,7 +41,7 @@
       </Testables>
    </TestAction>
    <LaunchAction
-      buildConfiguration = "Debug"
+      buildConfiguration = "Release"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
       launchStyle = "0"

TariCrypto/Model/TariKey.swift

@@ -53,6 +53,14 @@ public struct TariKey: CustomStringConvertible {
         self.bytes = bytes
     }
 
+    public init?(hexString: String) {
+        if let bytes = hexStringToBytes(hexString: hexString) {
+            self.bytes = bytes
+        } else {
+            return nil
+        }
+    }
+
     public func signMessage(message: String) throws -> TariSignedMessage {
         // FFI interface needs to change, this can be done cleaner
         // (C arrays are imported in swift as arrays of tuples, not values)

TariCrypto/TariUtil.swift

@@ -51,3 +51,25 @@ func bytesToHexString(bytes: ByteArray) -> String {
         + String(format: "%02X", bytes.28) + String(format: "%02X", bytes.29)
         + String(format: "%02X", bytes.30) + String(format: "%02X", bytes.31)
 }
+
+
+func hexStringToBytes(hexString: String) -> ByteArray? {
+    let stringArray = Array(hexString)
+    var data: Data = Data()
+    for i in stride(from: 0, to: hexString.count, by: 2) {
+        let pair: String = String(stringArray[i]) + String(stringArray[i+1])
+        if let byteNum = UInt8(pair, radix: 16) {
+            let byte = Data([byteNum])
+            data.append(byte)
+        }
+        else{
+            return nil
+        }
+    }
+    return (
+        data[0], data[1], data[2], data[3], data[4], data[5], data[6], data[7],
+        data[8], data[9], data[10], data[11], data[12], data[13], data[14], data[15],
+        data[16], data[17], data[18], data[19], data[20], data[21], data[22], data[23],
+        data[24], data[25], data[26], data[27], data[28], data[29], data[30], data[31]
+    )
+}

TariCryptoTests/TariCryptoTests.swift

@@ -44,13 +44,23 @@ class TariCryptoTests: XCTestCase {
         // Put teardown code here. This method is called after the invocation of each test method in the class.
     }
 
+    func testKeyFromHex() {
+        let keyPair = TariKeyPair.generateRandom()
+        let publicKeyFromHexString = "\(keyPair.publicKey)"
+        XCTAssertEqual("\(keyPair.publicKey)", "\(publicKeyFromHexString)")
+    }
+
     func testSignatureVerification() throws {
         let message = "A random message."
         let keyPair = TariKeyPair.generateRandom()
         print("Generated key pair: \(keyPair)")
         let signedMessage = try keyPair.privateKey.signMessage(message: message)
         print("Signed message: \(signedMessage)")
         XCTAssertTrue(try keyPair.publicKey.verifySignature(signedMessage: signedMessage))
+        // also try to verify with hex-generated public key
+        let publicKeyFromHex = TariKey(hexString: "\(keyPair.publicKey)")
+        XCTAssertNotNil(publicKeyFromHex)
+        XCTAssertTrue(try publicKeyFromHex?.verifySignature(signedMessage: signedMessage) ?? false)
     }
 
     func testSignatureFailure() throws {
@@ -69,12 +79,13 @@ class TariCryptoTests: XCTestCase {
         XCTAssertFalse(try keyPair.publicKey.verifySignature(signedMessage: signedMessage))
     }
 
+    /*
     func testPerformanceExample() throws {
         // This is an example of a performance test case.
         self.measure {
             // Put the code you want to measure the time of here.
         }
     }
-
+    */
 
 }