🧹 Make code Swiftier

.swiftpm/xcode/xcshareddata/xcschemes/Biscuit.xcscheme

@@ -90,6 +90,62 @@
                ReferencedContainer = "container:">
             </BuildableReference>
          </BuildActionEntry>
+         <BuildActionEntry
+            buildForTesting = "YES"
+            buildForRunning = "YES"
+            buildForProfiling = "YES"
+            buildForArchiving = "YES"
+            buildForAnalyzing = "YES">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "BiscuitDatalog"
+               BuildableName = "BiscuitDatalog"
+               BlueprintName = "BiscuitDatalog"
+               ReferencedContainer = "container:">
+            </BuildableReference>
+         </BuildActionEntry>
+         <BuildActionEntry
+            buildForTesting = "YES"
+            buildForRunning = "YES"
+            buildForProfiling = "YES"
+            buildForArchiving = "YES"
+            buildForAnalyzing = "YES">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "BiscuitFormat"
+               BuildableName = "BiscuitFormat"
+               BlueprintName = "BiscuitFormat"
+               ReferencedContainer = "container:">
+            </BuildableReference>
+         </BuildActionEntry>
+         <BuildActionEntry
+            buildForTesting = "YES"
+            buildForRunning = "YES"
+            buildForProfiling = "YES"
+            buildForArchiving = "YES"
+            buildForAnalyzing = "YES">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "BiscuitShared"
+               BuildableName = "BiscuitShared"
+               BlueprintName = "BiscuitShared"
+               ReferencedContainer = "container:">
+            </BuildableReference>
+         </BuildActionEntry>
+         <BuildActionEntry
+            buildForTesting = "YES"
+            buildForRunning = "YES"
+            buildForProfiling = "YES"
+            buildForArchiving = "YES"
+            buildForAnalyzing = "YES">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "BiscuitToken"
+               BuildableName = "BiscuitToken"
+               BlueprintName = "BiscuitToken"
+               ReferencedContainer = "container:">
+            </BuildableReference>
+         </BuildActionEntry>
       </BuildActionEntries>
    </BuildAction>
    <TestAction
@@ -124,6 +180,16 @@
                ReferencedContainer = "container:">
             </BuildableReference>
          </TestableReference>
+         <TestableReference
+            skipped = "NO">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "BiscuitDatalogTests"
+               BuildableName = "BiscuitDatalogTests"
+               BlueprintName = "BiscuitDatalogTests"
+               ReferencedContainer = "container:">
+            </BuildableReference>
+         </TestableReference>
       </Testables>
    </TestAction>
    <LaunchAction

Package.swift

@@ -17,7 +17,7 @@ let package = Package(
 	],
 	products: [
 		// Products define the executables and libraries a package produces, and make them visible to other packages.
-		.library(name: "Biscuit", targets: ["Datalog", "BiscuitCrypto", "Format"]),
+		.library(name: "Biscuit", targets: ["BiscuitDatalog", "BiscuitCrypto", "BiscuitFormat"]),
 	],
 	dependencies: [
 		.package(url: "https://github.com/apple/swift-collections", .upToNextMinor(from: "0.0.2")),
@@ -27,24 +27,28 @@ let package = Package(
 	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 this package depends on.
+		.target(name: "BiscuitShared"),
 		.target(
-			name: "Datalog",
+			name: "BiscuitDatalog",
 			dependencies: [
+				.target(name: "BiscuitShared"),
 				.product(name: "OrderedCollections", package: "swift-collections"),
 			]
 		),
-		.testTarget(name: "DatalogTests", dependencies: ["Datalog"]),
+		.testTarget(name: "BiscuitDatalogTests", dependencies: ["BiscuitDatalog"]),
 		.target(
 			name: "BiscuitCrypto",
 			dependencies: [
+				.target(name: "BiscuitShared"),
 				.product(name: "Crypto", package: "swift-crypto"),
 			]
 		),
 		.testTarget(name: "BiscuitCryptoTests", dependencies: ["BiscuitCrypto"]),
 		.target(
-			name: "Format",
+			name: "BiscuitFormat",
 			dependencies: [
-				.target(name: "Datalog"),
+				.target(name: "BiscuitShared"),
+				.target(name: "BiscuitDatalog"),
 				.target(name: "BiscuitCrypto"),
 				.product(name: "SwiftProtobuf", package: "swift-protobuf"),
 				.product(name: "OrderedCollections", package: "swift-collections"),

Sources/BiscuitCrypto/BiscuitCrypto.swift

@@ -1,6 +1,6 @@
 //
 //  BiscuitCrypto.swift
-//  BiscuitCrypto
+//  Biscuit
 //
 //  Created by Rémi Bardon on 09/09/2021.
 //
@@ -26,11 +26,7 @@ public struct KeyPair {
 	public let privateKey: PrivateKey
 	public var publicKey: PublicKey { privateKey.publicKey }
 
-	public init() {
-		self.privateKey = .init()
-	}
-
-	public init(from privateKey: PrivateKey) {
+	public init(from privateKey: PrivateKey = PrivateKey()) {
 		self.privateKey = privateKey
 	}
 
@@ -63,6 +59,16 @@ public struct Block {
 		self.signature = signature
 	}
 
+	public func verifySignature(with publicKey: PublicKey) throws {
+		var toVerify = self.data
+		toVerify.append(self.nextKey.rawRepresentation)
+
+		// FIXME: Replace with SHA512 hashing
+		guard publicKey.isValidSignature(self.signature, for: toVerify) else {
+			throw CryptoError.signature(.invalidSignature("The block has not been signed with the correct key"))
+		}
+	}
+
 }
 
 public struct Token {
@@ -78,17 +84,15 @@ public struct Token {
 		self.next = next
 	}
 
-	public init(keyPair: KeyPair, nextKey: KeyPair, message: Data) throws {
-		let signature = try sign(keyPair: keyPair, nextKey: nextKey, message: message)
+	public init(with message: Data, signedBy keyPair: KeyPair, nextKey: KeyPair) throws {
+		let signature = try sign(message, with: keyPair, nextKey: nextKey)
 		let block = Block(data: message, nextKey: nextKey.publicKey, signature: signature)
 
 		self.init(root: keyPair.publicKey, blocks: [block], next: .secret(nextKey.privateKey))
 	}
 
-	public func append(nextKey: KeyPair, message: Data) throws -> Self {
-		let keyPair = try self.next.keyPair()
-
-		let signature = try sign(keyPair: keyPair, nextKey: nextKey, message: message)
+	public func append(_ message: Data, nextKey: KeyPair) throws -> Self {
+		let signature = try sign(message, with: self.next.keyPair(), nextKey: nextKey)
 		let block = Block(data: message, nextKey: nextKey.publicKey, signature: signature)
 
 		var newToken = Token(root: self.root, blocks: self.blocks, next: .secret(nextKey.privateKey))
@@ -97,32 +101,35 @@ public struct Token {
 		return newToken
 	}
 
-	public func verify(with root: PublicKey) throws {
-		// FIXME: Try batched signature verification
-		var currentPub = root
-
+	public func verify(with rootPublicKey: PublicKey) throws {
 		// Verify all blocks
-		for block in self.blocks {
-			try verifyBlockSignature(of: block, with: currentPub)
+		let lastPublicKey: PublicKey = try {
+			var currentPublicKey = rootPublicKey
 
-			currentPub = block.nextKey
-		}
+			// FIXME: Try batched signature verification
+			for block in self.blocks {
+				try block.verifySignature(with: currentPublicKey)
+				currentPublicKey = block.nextKey
+			}
+
+			return currentPublicKey
+		}()
 
 		switch self.next {
-		case let .secret(privateKey):
-			if currentPub.rawRepresentation != privateKey.publicKey.rawRepresentation {
-				throw FormatError.signature(.invalidSignature("The last public key does not match the private key"))
+		case .secret(let privateKey):
+			guard lastPublicKey.rawRepresentation == privateKey.publicKey.rawRepresentation else {
+				throw CryptoError.signature(.invalidSignature("The last public key does not match the private key"))
 			}
-		case let .seal(signature):
-			// FIXME: Replace with SHA512 hashing
+		case .seal(let signature):
 			var toVerify = Data()
 			for block in self.blocks {
 				toVerify.append(block.data)
 				toVerify.append(block.nextKey.rawRepresentation)
 			}
 
-			guard currentPub.isValidSignature(signature, for: toVerify) else {
-				throw FormatError.signature(.invalidSignature("Block signature is invalid"))
+			// FIXME: Replace with SHA512 hashing
+			guard lastPublicKey.isValidSignature(signature, for: toVerify) else {
+				throw CryptoError.signature(.invalidSignature("Block signature is invalid"))
 			}
 		}
 	}
@@ -136,36 +143,26 @@ public enum NextToken {
 	public func keyPair() throws -> KeyPair {
 		switch self {
 		case .seal:
-			throw TokenError.sealed
+			throw CryptoError.sealed
 		case let .secret(privateKey):
 			return KeyPair(from: privateKey)
 		}
 	}
 
 }
 
-public func sign(keyPair: KeyPair, nextKey: KeyPair, message: Data) throws -> Signature {
+public func sign(_ message: Data, with keyPair: KeyPair, nextKey: KeyPair) throws -> Signature {
 	var toSign = message
 	toSign.append(nextKey.publicKey.rawRepresentation)
-
-	return try sign(keyPair: keyPair, message: toSign)
+	
+	return try sign(toSign, with: keyPair)
 }
 
-public func sign(keyPair: KeyPair, message: Data) throws -> Signature {
+public func sign(_ message: Data, with keyPair: KeyPair) throws -> Signature {
 	// FIXME: replace with SHA512 hashing
 	do {
 		return try keyPair.privateKey.signature(for: message)
 	} catch {
-		throw FormatError.signature(.invalidSignatureGeneration(error))
-	}
-}
-
-public func verifyBlockSignature(of block: Block, with publicKey: PublicKey) throws {
-	// FIXME: Replace with SHA512 hashing
-	var toVerify = block.data
-	toVerify.append(block.nextKey.rawRepresentation)
-
-	guard publicKey.isValidSignature(block.signature, for: toVerify) else {
-		throw FormatError.signature(.invalidSignature("The block has not been signed with the correct key"))
+		throw CryptoError.signature(.invalidSignatureGeneration(error))
 	}
 }

Sources/BiscuitCrypto/CryptoError.swift

@@ -0,0 +1,54 @@
+//
+//  CryptoError.swift
+//  Biscuit
+//
+//  Created by Rémi Bardon on 15/09/2021.
+//
+
+import Foundation
+import BiscuitShared
+
+extension BiscuitError {
+
+	internal static func crypto(_ error: CryptoError) -> Self {
+		return Self.error(prefix: "Error in the token's cryptographic signature", error: error)
+	}
+
+}
+
+/// Errors related to the token's cryptographic signature
+public enum CryptoError: Error, CustomStringConvertible {
+
+	case signature(SignatureError)
+	case sealed
+
+	public var description: String {
+		switch self {
+		case .signature(let error):
+			return "Failed verifying the signature: \(error)"
+		case .sealed:
+			return "Tried to append a block to a sealed token"
+		}
+	}
+
+}
+
+/// Signature errors
+public enum SignatureError: Error, CustomStringConvertible {
+
+//	case invalidFormat
+	case invalidSignature(String)
+	case invalidSignatureGeneration(Error)
+
+	public var description: String {
+		switch self {
+//		case .invalidFormat:
+//			return "Could not parse the signature elements"
+		case .invalidSignature(let error):
+			return "The signature did not match: \(error)"
+		case .invalidSignatureGeneration(let error):
+			return "Could not sign: \(error)"
+		}
+	}
+
+}