perf(ios): optimize swift code

packages/native_crypto_ios/ios/Classes/SwiftNativeCryptoIosPlugin.swift

@@ -3,93 +3,144 @@ import UIKit
 
 @available(iOS 13.0, *)
 public class SwiftNativeCryptoIosPlugin: NSObject, FlutterPlugin {
+    static let name: String = "plugins.hugop.cl/native_crypto"
+    
     public static func register(with registrar: FlutterPluginRegistrar) {
-    let channel = FlutterMethodChannel(name: "plugins.hugop.cl/native_crypto", binaryMessenger: registrar.messenger())
+        let channel = FlutterMethodChannel(name: name, binaryMessenger: registrar.messenger())
         let instance = SwiftNativeCryptoIosPlugin()
         registrar.addMethodCallDelegate(instance, channel: channel)
     }
     
     public func handle(_ call: FlutterMethodCall, result: @escaping FlutterResult) {
         switch call.method {
-    case "digest":
+        case "digest": _call(task: handleDigest(call: call), result: result)
+        case "generateSecretKey": _call(task: handleGenerateSecretKey(call: call), result: result)
+        case "pbkdf2": _call(task: handlePbkdf2(call: call), result: result)
+        case "encryptAsList": _call(task: handleEncryptAsList(call: call), result: result)
+        case "decryptAsList": _call(task: handleDecryptAsList(call: call), result: result)
+        case "encrypt": _call(task: handleCrypt(call: call, forEncryption: true), result: result)
+        case "decrypt": _call(task: handleCrypt(call: call, forEncryption: false), result: result)
+        default: result(FlutterMethodNotImplemented)
+        }
+    }
+    
+    private func _call<T>(task: Task<T>, result: @escaping FlutterResult) {
+        task.call()
+        task.finalize(callback: {(task: Task<T>) in
+            if (task.isSuccessful()) {
+                result(task.getResult()!)
+            } else {
+                let exception: Error = task.getException()
+                let message = exception.localizedDescription
+                result(FlutterError(code: "native_crypto", message: message, details: nil))
+            }
+        })
+    }
+    
+    private func handleDigest(call: FlutterMethodCall) -> Task<FlutterStandardTypedData> {
+        return Task(task: {
             let args : NSDictionary = call.arguments as! NSDictionary
             
             let data : Data = (args["data"] as! FlutterStandardTypedData).data
-        let algo : String = args["algorithm"] as! String
+            let algorithm : String = args["algorithm"] as! String
-        let algorithm : HashAlgorithm? = HashAlgorithm.init(rawValue: algo)
+            
-        // TODO(hpcl): check if algorithm is null
+            return FlutterStandardTypedData.init(bytes: try HashAlgorithm.digest(data: data, algorithm: algorithm))
-        // TODO(hpcl): check if digest is null
+        })
-        result(FlutterStandardTypedData.init(bytes: Hash.digest(data: data, algorithm: algorithm!)))
+    }
-    case "generateSecretKey":
+    
+    private func handleGenerateSecretKey(call: FlutterMethodCall) -> Task<FlutterStandardTypedData> {
+        return Task(task: {
             let args : NSDictionary = call.arguments as! NSDictionary
             
             let bitsCount : NSNumber = args["bitsCount"] as! NSNumber
-        // TODO(hpcl): check if secure random is null
+            
-        result(FlutterStandardTypedData.init(bytes: Key.fromSecureRandom(bitsCount: bitsCount.intValue)))
+            return FlutterStandardTypedData.init(bytes: SecretKey(fromSecureRandom: bitsCount.intValue).bytes)
-    case "generateKeyPair":
+        })
-        result(FlutterStandardTypedData.init(bytes: KeyPair.fromCurve()))
+    }
-    case "pbkdf2":
+    
+    private func handlePbkdf2(call: FlutterMethodCall) -> Task<FlutterStandardTypedData> {
+        return Task(task: {
             let args : NSDictionary = call.arguments as! NSDictionary
             
             let password : String = args["password"] as! String
             let salt : String = args["salt"] as! String
             let keyBytesCount : NSNumber = args["keyBytesCount"] as! NSNumber
             let iterations : NSNumber = args["iterations"] as! NSNumber
-        let algo : String = args["algorithm"] as! String
+            let algorithm : String = args["algorithm"] as! String
-        let algorithm : HashAlgorithm? = HashAlgorithm.init(rawValue: algo)
+            
-        // TODO(hpcl): check if algorithm is null
+            let pbkdf2 : Pbkdf2 = Pbkdf2(keyBytesCount: keyBytesCount.intValue, iterations: iterations.intValue)
-        // TODO(hpcl): check if derivation is null
+            pbkdf2.hash = HashAlgorithm.init(rawValue: algorithm) ?? pbkdf2.hash
-        result(FlutterStandardTypedData.init(bytes: Key.fromPBKDF2(password: password, salt: salt, keyBytesCount: keyBytesCount.intValue, iterations: iterations.intValue, algorithm: algorithm!)!))
+            pbkdf2.initialize(password: password, salt: salt)
-    case "encrypt":
+            
+            return FlutterStandardTypedData.init(bytes: try pbkdf2.derive().bytes)
+        })
+    }
+    
+    private func handleEncryptAsList(call: FlutterMethodCall) -> Task<Array<Data>> {
+        return Task(task: {
             let args : NSDictionary = call.arguments as! NSDictionary
             
             let data : Data = (args["data"] as! FlutterStandardTypedData).data
             let key : Data = (args["key"] as! FlutterStandardTypedData).data
-        let algo : String = args["algorithm"] as! String
+            let algorithm : String = args["algorithm"] as! String
-        // TODO(hpcl): check if algorithm is null
+            
-        // TODO(hpcl): check if ciphertext is null
+            let cipherAlgorithm : CipherAlgorithm? = CipherAlgorithm.init(rawValue: algorithm)
-        var ciphertext : Data
+            var cipher : Cipher
-        switch algo {
+            if (cipherAlgorithm != nil) {
-        case "aes":
+                cipher = cipherAlgorithm!.getCipher
-            ciphertext = AESCipher.encrypt(plaintext: data, key: key)!
+            } else {
-        case "chachapoly":
+                throw NativeCryptoError.cipherError
-            ciphertext = CHACHACipher.encrypt(plaintext: data, key: key)!
-        default:
-            ciphertext = Data.init();
             }
-        result(FlutterStandardTypedData.init(bytes: ciphertext))
+            
-    case "decrypt":
+            return try cipher.encryptAsList(data: data, key: key)
+        })
+    }
+    
+    private func handleDecryptAsList(call: FlutterMethodCall) -> Task<FlutterStandardTypedData> {
+        return Task(task: {
+            let args : NSDictionary = call.arguments as! NSDictionary
+            
+            let data = args["data"] as! NSArray
+            let key : Data = (args["key"] as! FlutterStandardTypedData).data
+            let algorithm : String = args["algorithm"] as! String
+            
+            let iv = (data[0] as! FlutterStandardTypedData).data
+            let encrypted = (data[1] as! FlutterStandardTypedData).data
+            
+            let cipherAlgorithm : CipherAlgorithm? = CipherAlgorithm.init(rawValue: algorithm)
+            var cipher : Cipher
+            if (cipherAlgorithm != nil) {
+                cipher = cipherAlgorithm!.getCipher
+            } else {
+                throw NativeCryptoError.cipherError
+            }
+            
+            return FlutterStandardTypedData.init(bytes: try cipher.decryptAsList(data: [iv, encrypted], key: key))
+        })
+    }
+    
+    private func handleCrypt(call: FlutterMethodCall, forEncryption: Bool) -> Task<FlutterStandardTypedData> {
+        return Task(task: {
             let args : NSDictionary = call.arguments as! NSDictionary
             
             let data : Data = (args["data"] as! FlutterStandardTypedData).data
             let key : Data = (args["key"] as! FlutterStandardTypedData).data
-        let algo : String = args["algorithm"] as! String
+            let algorithm : String = args["algorithm"] as! String
-        // TODO(hpcl): check if algorithm is null
-        // TODO(hpcl): check if ciphertext is null
-        var ciphertext : Data
-        switch algo {
-        case "aes":
-            ciphertext = AESCipher.decrypt(ciphertext: data, key: key)!
-        case "chachapoly":
-            ciphertext = CHACHACipher.decrypt(ciphertext: data, key: key)!
-        default:
-            ciphertext = Data.init();
-        }
-        result(FlutterStandardTypedData.init(bytes: ciphertext))
-    case "generateSharedSecretKey":
-        let args : NSDictionary = call.arguments as! NSDictionary
             
-        let salt : Data = (args["salt"] as! FlutterStandardTypedData).data
+            let cipherAlgorithm : CipherAlgorithm? = CipherAlgorithm.init(rawValue: algorithm)
-        let keyBytesCount : NSNumber = args["keyBytesCount"] as! NSNumber
+            var cipher : Cipher
-        let ephemeralPrivateKey : Data = (args["ephemeralPrivateKey"] as! FlutterStandardTypedData).data
+            if (cipherAlgorithm != nil) {
-        let otherPublicKey : Data = (args["otherPublicKey"] as! FlutterStandardTypedData).data
+                cipher = cipherAlgorithm!.getCipher
-        let hkdfAlgorithm : String = args["hkdfAlgorithm"] as! String
+            } else {
-        let algorithm : HashAlgorithm? = HashAlgorithm.init(rawValue: hkdfAlgorithm)
+                throw NativeCryptoError.cipherError
-        // TODO(hpcl): check if algorithm is null
+            }
-        // TODO(hpcl): check if generated key is null
-        result(FlutterStandardTypedData.init(bytes: ECDH.generateSharedSecretKey(salt: salt, hash: algorithm!, keyBytesCount: keyBytesCount.intValue, privateKey: ephemeralPrivateKey, publicKey: otherPublicKey)!))
             
-    default: result(FlutterMethodNotImplemented)
+            if (forEncryption) {
+                return FlutterStandardTypedData.init(bytes: try cipher.encrypt(data: data, key: key))
+            } else {
+                return FlutterStandardTypedData.init(bytes: try cipher.decrypt(data: data, key: key))
             }
+        })
     }
+    
 }

packages/native_crypto_ios/ios/Classes/ciphers/AESCipher.swift

@@ -1,28 +1,57 @@
 //
-//  AES.swift
+//  AESCipher.swift
 //  native_crypto_ios
 //
 //  Created by Hugo Pointcheval on 25/05/2022.
 //
 
 import Foundation
+import CryptoKit
+
+class AESCipher : Cipher {
+    var algorithm: CipherAlgorithm = CipherAlgorithm.aes
     
-class AES : Cipher {
     /// Encrypts plaintext with key using AES GCM
     @available(iOS 13.0, *)
-    static func encrypt(plaintext: Data, key: Data) -> Data? {
+    func encrypt(data: Data, key: Data) throws -> Data {
-        let symmetricKey = SymmetricKey.init(data: key)
+        let symmetricKey : SymmetricKey = SymmetricKey.init(data: key)
-        let encrypted = try? AES.GCM.seal(plaintext, using: symmetricKey)
+        let encrypted : AES.GCM.SealedBox? = try? AES.GCM.seal(data, using: symmetricKey)
-        return encrypted?.combined
+        
+        let encryptedData : Data? = encrypted?.combined
+        if (encryptedData == nil) {
+            throw NativeCryptoError.encryptionError
+        }
+        return encryptedData!
     }
     
     /// Decrypts ciphertext with key using AES GCM
     @available(iOS 13.0, *)
-    static func decrypt(ciphertext: Data, key: Data) -> Data? {
+    func decrypt(data: Data, key: Data) throws -> Data {
         let symmetricKey = SymmetricKey.init(data: key)
-        let sealedBox = try? AES.GCM.SealedBox(combined: ciphertext)
+        let sealedBox = try? AES.GCM.SealedBox(combined: data)
-        if (sealedBox == nil) { return nil }
+        if (sealedBox == nil) { return Data.init() }
         let decryptedData = try? AES.GCM.open(sealedBox!, using: symmetricKey)
+        if (decryptedData == nil) {
+            throw NativeCryptoError.decryptionError
+        }
+        return decryptedData!
+    }
+    
+    func encryptAsList(data: Data, key: Data) throws -> [Data] {
+        let encryptedData = try encrypt(data: data, key: key)
+        
+        let iv = encryptedData.prefix(12)
+        let data = encryptedData.suffix(from: 12)
+        
+        return [iv, data]
+    }
+    
+    func decryptAsList(data: [Data], key: Data) throws -> Data {
+        var encryptedData = data.first!
+        let data = data.last!
+        encryptedData.append(data)
+        
+        let decryptedData = try decrypt(data: encryptedData, key: key)
         return decryptedData
     }
 }

packages/native_crypto_ios/ios/Classes/kdf/Pbkdf2.swift

@@ -6,3 +6,58 @@
 //
 
 import Foundation
+import CommonCrypto
+
+class Pbkdf2 : KeyDerivation {
+    var algorithm: KdfAlgorithm = KdfAlgorithm.pbkdf2
+    
+    var keyBytesCount: Int
+    var iterations: Int
+    var hash: HashAlgorithm = HashAlgorithm.HashSHA256
+    
+    var password: String? = nil
+    var salt: String? = nil
+    
+    init(keyBytesCount: Int, iterations: Int) {
+        self.keyBytesCount = keyBytesCount
+        self.iterations = iterations
+    }
+    
+    func initialize(password: String, salt: String) {
+        self.password = password
+        self.salt = salt
+    }
+    
+    func derive() throws -> SecretKey {
+        if (password == nil || salt == nil) {
+            throw NativeCryptoError.pbkdf2Error
+        }
+        
+        let passwordData = password!.data(using: .utf8)!
+        let saltData = salt!.data(using: .utf8)!
+        
+        var derivedKeyData = Data(repeating: 0, count: keyBytesCount)
+        let localDerivedKeyData = derivedKeyData
+        
+        let status = derivedKeyData.withUnsafeMutableBytes { (derivedKeyBytes: UnsafeMutableRawBufferPointer) in
+            saltData.withUnsafeBytes { (saltBytes: UnsafeRawBufferPointer) in
+                CCKeyDerivationPBKDF(
+                    CCPBKDFAlgorithm(kCCPBKDF2),
+                    password,
+                    passwordData.count,
+                    saltBytes.bindMemory(to: UInt8.self).baseAddress,
+                    saltData.count,
+                    hash.pbkdf2identifier,
+                    UInt32(iterations),
+                    derivedKeyBytes.bindMemory(to: UInt8.self).baseAddress,
+                    localDerivedKeyData.count)
+            }
+        }
+        
+        if (status != kCCSuccess) {
+            throw NativeCryptoError.pbkdf2Error
+        }
+        
+        return SecretKey(derivedKeyData)
+    }
+}

packages/native_crypto_ios/ios/Classes/keys/SecretKey.swift

@@ -6,3 +6,20 @@
 //
 
 import Foundation
+import CryptoKit
+
+class SecretKey : Key {
+    var bytes: Data
+    
+    init(_ bytes: Data) {
+        self.bytes = bytes
+    }
+    
+    init(fromSecureRandom bitsCount: Int) {
+        let symmetricKey = SymmetricKey.init(size: SymmetricKeySize(bitCount: bitsCount))
+        bytes = symmetricKey.withUnsafeBytes
+        {
+            return Data(Array($0))
+        }
+    }
+}

packages/native_crypto_ios/ios/Classes/protocols/Cipher.swift

@@ -6,3 +6,11 @@
 //
 
 import Foundation
+
+protocol Cipher {
+    var algorithm: CipherAlgorithm { get }
+    func encrypt(data: Data, key: Data) throws -> Data
+    func decrypt(data: Data, key: Data) throws -> Data
+    func encryptAsList(data: Data, key: Data) throws -> [Data]
+    func decryptAsList(data: [Data], key: Data) throws-> Data
+}

packages/native_crypto_ios/ios/Classes/protocols/Key.swift

@@ -6,3 +6,7 @@
 //
 
 import Foundation
+
+protocol Key {
+    var bytes: Data { get set }
+}

packages/native_crypto_ios/ios/Classes/protocols/KeyDerivation.swift

@@ -6,3 +6,8 @@
 //
 
 import Foundation
+
+protocol KeyDerivation {
+    var algorithm : KdfAlgorithm { get }
+    func derive() throws -> SecretKey
+}

packages/native_crypto_ios/ios/Classes/utils/CipherAlgorithm.swift

@@ -6,3 +6,13 @@
 //
 
 import Foundation
+
+enum CipherAlgorithm : String {
+    case aes = "aes"
+    
+    var getCipher: Cipher {
+        switch self {
+        case .aes: return AESCipher()
+        }
+    }
+}

packages/native_crypto_ios/ios/Classes/utils/HashAlgorithm.swift

@@ -6,3 +6,40 @@
 //
 
 import Foundation
+import CommonCrypto
+import CryptoKit
+
+enum HashAlgorithm: String {
+    case HashSHA256 = "sha256"
+    case HashSHA384 = "sha384"
+    case HashSHA512 = "sha512"
+    
+    var pbkdf2identifier: UInt32 {
+        switch self {
+        case .HashSHA256: return CCPBKDFAlgorithm(kCCPRFHmacAlgSHA256)
+        case .HashSHA384: return CCPBKDFAlgorithm(kCCPRFHmacAlgSHA384)
+        case .HashSHA512: return CCPBKDFAlgorithm(kCCPRFHmacAlgSHA512)
+        }
+    }
+    
+    @available(iOS 13.0, *)
+    func digest(data: Data) -> Data {
+        switch self {
+        case .HashSHA256:
+            return Data(SHA256.hash(data: data))
+        case .HashSHA384:
+            return Data(SHA384.hash(data: data))
+        case .HashSHA512:
+            return Data(SHA512.hash(data: data))
+        }
+    }
+    
+    @available(iOS 13.0, *)
+    static func digest(data: Data, algorithm: String) throws -> Data {
+        let algo = HashAlgorithm.init(rawValue: algorithm)
+        if (algo == nil) {
+            throw NativeCryptoError.messageDigestError
+        }
+        return algo!.digest(data: data)
+    }
+}

packages/native_crypto_ios/ios/Classes/utils/KdfAlgorithm.swift

@@ -6,3 +6,7 @@
 //
 
 import Foundation
+
+enum KdfAlgorithm {
+    case pbkdf2
+}

packages/native_crypto_ios/ios/Classes/utils/NativeCryptoError.swift

@@ -6,3 +6,13 @@
 //
 
 import Foundation
+
+enum NativeCryptoError : Error {
+case decryptionError
+case encryptionError
+case messageDigestError
+case pbkdf2Error
+case cipherError
+case resultError
+case exceptionError
+}

packages/native_crypto_ios/ios/Classes/utils/Task.swift

@@ -6,3 +6,47 @@
 //
 
 import Foundation
+
+class Task<T> {
+    
+    var task: () throws -> T
+    private var successful: Bool = false
+    private var result: T? = nil
+    private var exception: Error? = nil
+    
+    init(task: @escaping () throws -> T) {
+        self.task = task
+    }
+    
+    func isSuccessful() -> Bool {
+        return successful
+    }
+    
+    func getResult() -> T? {
+        return result
+    }
+    
+    func getException() -> Error {
+        if (exception != nil) {
+            return exception!
+        } else {
+            return NativeCryptoError.exceptionError
+        }
+    }
+    
+    func call() {
+        do {
+            result = try task()
+            exception = nil
+            successful = true
+        } catch {
+            exception = error
+            result = nil
+            successful = false
+        }
+    }
+    
+    func finalize(callback: (_ task: Task<T>) -> Void) {
+        callback(self)
+    }
+}