From 9007fded5661f42169eaa86752f3fdc2e0f5db4e Mon Sep 17 00:00:00 2001
From: Pointcheval Hugo <hugo@gitlab.pointcheval.fr>
Date: Sat, 19 Dec 2020 21:45:34 +0100
Subject: [PATCH] Add cipher class and cipher algorithm in swift

---
 ios/Classes/Cipher.swift | 135 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 135 insertions(+)
 create mode 100644 ios/Classes/Cipher.swift

diff --git a/ios/Classes/Cipher.swift b/ios/Classes/Cipher.swift
new file mode 100644
index 0000000..5d92895
--- /dev/null
+++ b/ios/Classes/Cipher.swift
@@ -0,0 +1,135 @@
+//
+//  Cipher.swift
+//
+//  NativeCryptoPlugin
+//
+//  Copyright (c) 2020
+//  Author: Hugo Pointcheval
+//
+
+import Foundation
+import CommonCrypto
+
+enum CipherAlgorithm: String {
+    case AES = "aes"
+    case BlowFish = "blowfish"
+    
+    var instance: Int {
+        switch self {
+        case .AES: return kCCAlgorithmAES
+        case .BlowFish: return kCCAlgorithmBlowfish
+        }
+    }
+}
+
+enum BlockCipherMode: String {
+    case ECB = "ecb"
+    case CBC = "cbc"
+    
+    var instance: Int {
+        switch self {
+        case .CBC: return 0
+        case .ECB: return kCCOptionECBMode
+        }
+    }
+}
+
+enum Padding: String {
+    case PKCS5 = "pkcs5"
+    case None = "none"
+    
+    var instance: Int {
+        switch self {
+        case .PKCS5: return kCCOptionPKCS7Padding
+        case .None: return 0
+        }
+    }
+}
+
+class Cipher {
+    func encrypt(data : Data, key : Data, algorithm : CipherAlgorithm, mode : BlockCipherMode, padding : Padding) -> [Data]? {
+        // Calculate Mac
+        let mac = Hash().digest(data: key + data, algorithm: .SHA256)
+        let payload = mac! + data
+        
+        // Generate IV
+        let ivBytes = UnsafeMutableRawPointer.allocate(byteCount: kCCBlockSizeAES128, alignment: 1)
+        defer { ivBytes.deallocate() }
+        let ivStatus = CCRandomGenerateBytes(ivBytes, kCCBlockSizeAES128)
+        if (ivStatus != kCCSuccess) {
+            return nil
+        }
+        let ivData = Data(bytes: ivBytes, count: kCCBlockSizeAES128)
+        
+        let algo = algorithm.instance
+        let options: CCOptions = UInt32(mode.instance + padding.instance)
+
+        
+        guard var ciphertext = crypt(operation: kCCEncrypt,
+                                    algorithm: algo,
+                                    options: options,
+                                    key: key,
+                                    initializationVector: ivData,
+                                    dataIn: payload) else { return nil }
+                
+        return [ciphertext, ivData]
+    }
+    
+    func decrypt(payload : [Data], key : Data, algorithm : CipherAlgorithm, mode : BlockCipherMode, padding : Padding) -> Data? {
+        let encrypted = payload[1] + payload[0]
+        
+        guard encrypted.count > kCCBlockSizeAES128 else { return nil }
+        let iv = encrypted.prefix(kCCBlockSizeAES128)
+        let ciphertext = encrypted.suffix(from: kCCBlockSizeAES128)
+        
+        let algo = algorithm.instance
+        let options: CCOptions = UInt32(mode.instance + padding.instance)
+        
+        guard var decrypted = crypt(operation: kCCDecrypt,
+                                    algorithm: algo,
+                                    options: options,
+                                    key: key,
+                                    initializationVector: iv,
+                                    dataIn: ciphertext) else {return nil}
+        
+        
+        // Create a range based on the length of data to return
+        let range = 0..<32
+
+        // Get a new copy of data
+        let mac = decrypted.subdata(in: range)
+        decrypted.removeSubrange(range)
+        
+        let vmac = Hash().digest(data: key + decrypted, algorithm: .SHA256)
+        
+        if (mac.base64EncodedData() == vmac!.base64EncodedData()) {
+            return decrypted
+        } else {
+            return nil
+        }
+    }
+    
+    private func crypt(operation: Int, algorithm: Int, options: UInt32, key: Data,
+            initializationVector: Data, dataIn: Data) -> Data? {
+        
+        return key.withUnsafeBytes { keyUnsafeRawBufferPointer in
+            return dataIn.withUnsafeBytes { dataInUnsafeRawBufferPointer in
+                return initializationVector.withUnsafeBytes { ivUnsafeRawBufferPointer in
+                    let dataOutSize: Int = dataIn.count + kCCBlockSizeAES128*2
+                    let dataOut = UnsafeMutableRawPointer.allocate(byteCount: dataOutSize,
+                        alignment: 1)
+                    defer { dataOut.deallocate() }
+                    var dataOutMoved: Int = 0
+                    let status = CCCrypt(CCOperation(operation), CCAlgorithm(algorithm),
+                        CCOptions(options),
+                        keyUnsafeRawBufferPointer.baseAddress, key.count,
+                        ivUnsafeRawBufferPointer.baseAddress,
+                        dataInUnsafeRawBufferPointer.baseAddress, dataIn.count,
+                        dataOut, dataOutSize, &dataOutMoved)
+                    guard status == kCCSuccess else { return nil }
+                    return Data(bytes: dataOut, count: dataOutMoved)
+                }
+            }
+        }
+    }
+}