解密 CommonCrypto 总是用 URLSession.shared.dataTask Data Swift 返回 nil

如何解决解密 CommonCrypto 总是用 URLSession.shared.dataTask Data Swift 返回 nil

我正在制作一个带有 java 后端和 Swift 前端的应用程序。使用 REST Api 移动数据。我希望使用 AES 128 CBC 加密数据。加密方法有效，但解密方法无效。

首先，这是用于 de AES 加密和解密的 Swift 代码：

import Foundation
import CommonCrypto

struct AES {

private let key: Data
private let iv: Data


init?() {
    let ivProduct: String = "dkghepfowntislqn"
    let keyProduct: String = "2949382094230487"
    
    guard keyProduct.count == kCCKeySizeAES128 || keyProduct.count == kCCKeySizeAES256,let keyData = keyProduct.data(using: .utf8) else {
        debugPrint("Error: Failed to set a key.")
        return nil
    }

    guard ivProduct.count == kCCBlockSizeAES128,let ivData = ivProduct.data(using: .utf8) else {
        debugPrint("Error: Failed to set an initial vector.")
        return nil
    }


    self.key = keyData
    self.iv  = ivData
}


func encrypt(string: String) -> Data? {
    return crypt(data: string.data(using: .utf8),option: CCOperation(kCCEncrypt))
}

func decrypt(data: Data?) -> String? {
    guard let decryptedData = crypt(data: data,option: CCOperation(kCCDecrypt)) else { return nil }
    return String(bytes: decryptedData,encoding: .utf8)
}

func crypt(data: Data?,option: CCOperation) -> Data? {
    guard let data = data else { return nil }

    let cryptLength = data.count + kCCBlockSizeAES128
    var cryptData   = Data(count: cryptLength)

    let keyLength = key.count
    let options   = CCOptions(kCCOptionPKCS7Padding)

    var bytesLength = Int(0)

    let status = cryptData.withUnsafeMutableBytes { cryptBytes in
        data.withUnsafeBytes { dataBytes in
            iv.withUnsafeBytes { ivBytes in
                key.withUnsafeBytes { keyBytes in
                CCCrypt(option,CCAlgorithm(kCCAlgorithmAES),options,keyBytes.baseAddress,keyLength,ivBytes.baseAddress,dataBytes.baseAddress,data.count,cryptBytes.baseAddress,cryptLength,&bytesLength)
                }
            }
        }
    }

    guard UInt32(status) == UInt32(kCCSuccess) else {
        debugPrint("Error: Failed to crypt data. Status \(status)")
        return nil
    }

    cryptData.removeSubrange(bytesLength..<cryptData.count)
    return cryptData
}
}

数据是从 REST API 收集的，如下所示：

func getTestAllPayments(_ completion: @escaping ([Payment]) -> ()) {
  let aes128 = AES()
  if let url = URL(string: "\(localhostUrl)/payment") {
           URLSession.shared.dataTask(with: url) { data,response,error in
              if let data = data {
                  do {
                    let res = try JSONDecoder().decode([Payment].self,from: (data))
                    print(res.self)
                    completion(res)
                    return
                  } catch let error {
                     print(error)
                  }
              }
           }.resume()
        }
    }

现在解决问题。我已经进行了几次测试：

首先检查加密和解密方法是否协同工作：

let aes128 = AES()
let dataEncrypt = aes128?.encrypt(string:"Hello") //Will be :lG7Bqk0nwx732eOQLAzhqQ==
let dataDecrypt = aes128?.decrypt(data:dataEncrypt) //Will be: "Hello"
print(dataDecrypt) --> //output = "Hello"

第一次测试很有魅力。对于第二个测试：

let aes128 = AES()
  if let url = URL(string: "\(localhostUrl)/payment") {
           URLSession.shared.dataTask(with: url) { data,error in
              if let data = data {

                print(String(data: data,encoding: .utf8)) //Output = lG7Bqk0nwx732eOQLAzhqQ==

                let dataDecrypt = aes128?.decrypt(data: data)
                print(dataDecrypt) --> //output = nil

这就是出错的地方。使用完全相同的编码字符串获取数据时，它将始终返回 nil。和URLSession返回的数据格式有关系吗？