AES decryption from JS backend to iOS app

Question

I'm working on 1 iOS app which gets encrypted data from API. I have tried converting JS code to the swift, but have not been able to do it. I'm stuck at the decryption part, in a later stage, I have to again encrypt it for API requests. JS Code is below:

function hexToBase64(str) {
  return btoa(String.fromCharCode.apply(null,
    str.replace(/\r|\n/g, "").replace(/([\da-fA-F]{2}) ?/g, "0x$1 ").replace(/ +$/, "").split(" "))
  );
}


function base64ToHex(str) {
  for (var i = 0, bin = atob(str.replace(/[ \r\n]+$/, "")), hex = []; i < bin.length; ++i) {
    var tmp = bin.charCodeAt(i).toString(16);
    if (tmp.length === 1) tmp = "0" + tmp;
    hex[hex.length] = tmp;
  }
  return hex.join("");
}

export function decryptFuncForNet(transitmessage, pass) {
  var hexResult = base64ToHex(transitmessage)
  var salt = CryptoJS.enc.Hex.parse(hexResult.substr(0, 64));
  var iv = CryptoJS.enc.Hex.parse(hexResult.substr(64, 32));
  var encrypted = hexToBase64(hexResult.substring(96));
  var key = CryptoJS.PBKDF2(pass, salt, {
    keySize: keySize / 32,
    iterations: iterations
  });
  var decrypted = CryptoJS.AES.decrypt(encrypted, key, {
    iv: iv,
    padding: CryptoJS.pad.Pkcs7,
    mode: CryptoJS.mode.CBC

  })
  return decrypted.toString(CryptoJS.enc.Utf8);
}

Can someone help me to convert it to swift functions? Or is there any pod/framework available for this?

Thank you in advance.

Answer 1

you could try something like this for hexResult:

        func hexToBase64(_ str: String) -> String {
            let hexdata = str.data(using: .utf8)!
            return hexdata.base64EncodedString()
        }
        
        func base64ToHex(_ str: String) -> String? {
            if let dataHex = Data(base64Encoded: hexResult),
               let decodedHex = String(data: dataHex, encoding: .utf8) {
                return decodedHex
            }
            return nil
        }
        
        // encrypt
        let transitmessage = "BA5E64C0DE"
        print("---> transitmessage: \(transitmessage)")
        let hexResult = hexToBase64(transitmessage)
        print("---> hexResult: \(hexResult)")
        
        // decrypt
        if let decodedHex = base64ToHex(hexResult) {
            print("---> decodedHex: \(decodedHex) \n")
        }