Add Ed25519 private and public key structs

.swiftlint.yml

@@ -0,0 +1,4 @@
+included:
+    - Sources
+excluded:
+    - Sources/hedera/protobuf

Package.resolved

@@ -0,0 +1,34 @@
+{
+  "object": {
+    "pins": [
+      {
+        "package": "Clibsodium",
+        "repositoryURL": "https://github.com/tiwoc/Clibsodium.git",
+        "state": {
+          "branch": null,
+          "revision": "2ac72772aae26b2da0b15c253d9bb79ba452f66a",
+          "version": "1.0.0"
+        }
+      },
+      {
+        "package": "SwiftProtobuf",
+        "repositoryURL": "https://github.com/apple/swift-protobuf",
+        "state": {
+          "branch": null,
+          "revision": "3a3594f84b746793c84c2ab2f1e855aaa9d3a593",
+          "version": "1.6.0"
+        }
+      },
+      {
+        "package": "Sodium",
+        "repositoryURL": "https://github.com/jedisct1/swift-sodium",
+        "state": {
+          "branch": null,
+          "revision": "5900a54dea817befa18f3148889fe922a38afe7f",
+          "version": "0.8.0"
+        }
+      }
+    ]
+  },
+  "version": 1
+}

Package.swift

@@ -5,22 +5,25 @@ import PackageDescription
 
 let package = Package(
     name: "hedera",
+    platforms: [
+        .macOS(.v10_13),
+    ],
     products: [
         // Products define the executables and libraries produced by a package, and make them visible to other packages.
         .library(
             name: "hedera",
             targets: ["hedera"]),
     ],
     dependencies: [
-        // Dependencies declare other packages that this package depends on.
-        // .package(url: /* package url */, from: "1.0.0"),
+        .package(url: "https://github.com/jedisct1/swift-sodium", from: "0.8.0"),
+        .package(url: "https://github.com/apple/swift-protobuf", from: "1.6.0")
     ],
     targets: [
         // Targets are the basic building blocks of a package. A target can define a module or a test suite.
         // Targets can depend on other targets in this package, and on products in packages which this package depends on.
         .target(
             name: "hedera",
-            dependencies: []),
+            dependencies: ["Sodium", "SwiftProtobuf"]),
         .testTarget(
             name: "hederaTests",
             dependencies: ["hedera"]),

Sources/hedera/crypto/PublicKey.swift

@@ -0,0 +1,25 @@
+import Foundation
+import Sodium
+
+// TODO
+public struct HederaError: Error {}
+
+public protocol PublicKey {
+    func toProtoKey() -> Proto_Key
+}
+
+extension PublicKey {
+//    static func from(proto key: Proto_Key) throws -> PublicKey {
+//        switch key.key! {
+//        case let .ed25519(data):
+//            return try! Ed25519PublicKey.from(bytes: Bytes(data))
+//        // TODO: case .contractID()
+//        default:
+//            // TODO: Unhandled Key Case error 
+//            throw HederaError()
+//        }
+//    }
+
+    // TODO
+    // static func from(string: String) -> PublicKey {}
+}

Sources/hedera/crypto/Utils.swift

@@ -0,0 +1,31 @@
+import Sodium
+
+let sodium = Sodium()
+
+struct HexDecodeError: Error {}
+
+func hexDecode<S>(_ hex: S) -> Result<Bytes, HexDecodeError> where S: StringProtocol {
+    if hex.count % 2 != 0 {
+        return .failure(HexDecodeError())
+    }
+
+    let bytesLen = hex.count / 2
+    var bytes = Bytes(repeating: 0, count: bytesLen)
+
+    for index in 0 ..< bytesLen {
+        let start = hex.index(hex.startIndex, offsetBy: index * 2)
+        let end = hex.index(start, offsetBy: 2)
+        bytes[index] = UInt8(hex[start ..< end], radix: 16)!
+    }
+
+    return .success(bytes)
+}
+
+func hexEncode<S>(bytes: Bytes, prefixed with: S) -> String where S: StringProtocol {
+    var result = String(with)
+    for byte in bytes {
+        result.append(String(format: "%02x", byte))
+    }
+
+    return result
+}

Sources/hedera/crypto/ed25519/Ed25519PrivateKey.swift

@@ -1,3 +1,72 @@
-// TODO
+import Sodium
+
+let ed25519PrivateKeyPrefix = "302e020100300506032b657004220420"
+let ed25519PrivateKeyLength = 32
+let combinedEd25519KeyLength = 64
+
+// TODO: how to handle error possibilities???
+struct InvalidKeyBytes: Error {}
+
 public struct Ed25519PrivateKey {
+    var inner: Bytes
+
+    private init(bytes: Bytes) {
+        inner = bytes
+    }
+
+    public static func from(bytes: Bytes) -> Result<Ed25519PrivateKey, Error> {
+        if bytes.count == ed25519PrivateKeyLength {
+            return .success(Ed25519PrivateKey(bytes: bytes))
+        } else if bytes.count == combinedEd25519KeyLength {
+            return .success(Ed25519PrivateKey(bytes: Bytes(bytes.prefix(ed25519PrivateKeyLength))))
+        }
+        return .failure(InvalidKeyBytes())
+    }
+
+    var bytes: Bytes {
+        return inner
+    }
+
+    public static func generate() -> Ed25519PrivateKey {
+        return Ed25519PrivateKey(bytes: sodium.box.keyPair()!.secretKey)
+    }
+
+    public func getPublicKey() -> Ed25519PublicKey {
+        return try! Ed25519PublicKey.from(bytes: sodium.box.keyPair(seed: inner)!.publicKey).get()
+    }
+}
+
+extension Ed25519PrivateKey: CustomStringConvertible {
+    public var description: String {
+        return hexEncode(bytes: inner, prefixed: ed25519PrivateKeyPrefix)
+    }
+}
+
+extension Ed25519PrivateKey: CustomDebugStringConvertible {
+    public var debugDescription: String {
+        return description
+    }
+}
+
+extension Ed25519PrivateKey: LosslessStringConvertible {
+    // Recover from a hex encoded string. Does not support key derivation.
+    public init?(_ description: String) {
+        switch description.count {
+        case ed25519PrivateKeyLength * 2, combinedEd25519KeyLength * 2: // lone key, or combined key
+            // This cannot fail to decode
+            // swiftlint:disable:next force_try
+            inner = try! Ed25519PrivateKey.from(bytes: try! hexDecode(description).get()).get().inner
+        case ed25519PrivateKeyLength * 2 + ed25519PrivateKeyPrefix.count: // DER encoded key
+            if description.hasPrefix(ed25519PrivateKeyPrefix) {
+                let range = description.index(description.startIndex, offsetBy: ed25519PrivateKeyPrefix.count)...
+                // This cannot fail to decode
+                // swiftlint:disable:next force_try
+                inner = try! Ed25519PrivateKey.from(bytes: try! hexDecode(description[range]).get()).get().inner
+            } else {
+                return nil
+            }
+        default:
+            return nil
+        }
+    }
 }

Sources/hedera/crypto/ed25519/Ed25519PublicKey.swift

@@ -1,3 +1,64 @@
-// TODO
+import Sodium
+import Foundation
+
+let ed25519PublicKeyPrefix = "302a300506032b6570032100"
+let ed25519PublicKeyLength = 32
+
 public struct Ed25519PublicKey {
+    let inner: Bytes
+
+    private init(bytes: Bytes) {
+        inner = bytes
+    }
+
+    static func from(bytes: Bytes) -> Result<Ed25519PublicKey, Error> {
+        if bytes.count == ed25519PublicKeyLength {
+            return .success(Ed25519PublicKey(bytes: bytes))
+        } else {
+            // TODO: actual error "invalid public key"
+            return .failure(HederaError())
+        }
+    }
+
+    var bytes: Bytes {
+        return inner
+    }
+}
+
+extension Ed25519PublicKey: PublicKey {
+    public func toProtoKey() -> Proto_Key {
+        var proto = Proto_Key()
+        proto.ed25519 = Data(inner)
+        return proto
+    }
+}
+
+extension Ed25519PublicKey: CustomStringConvertible {
+    public var description: String {
+        return hexEncode(bytes: inner, prefixed: ed25519PublicKeyPrefix)
+    }
+}
+
+extension Ed25519PublicKey: CustomDebugStringConvertible {
+    public var debugDescription: String {
+        return description
+    }
+}
+
+extension Ed25519PublicKey: LosslessStringConvertible {
+    public init?(_ description: String) {
+        switch description.count {
+        case ed25519PublicKeyLength * 2:
+            // This cannot fail
+            // swiftlint:disable:next force_try
+            inner = try! hexDecode(description).get()
+        case ed25519PublicKeyLength * 2 + ed25519PublicKeyPrefix.count:
+            let start = description.index(description.startIndex, offsetBy: ed25519PublicKeyPrefix.count)
+            // This cannot fail
+            // swiftlint:disable:next force_try
+            inner = try! hexDecode(description[start...]).get()
+        default:
+            return nil
+        }
+    }
 }