AES128 encryption in swift

Question

I’ve an issue with AES-128 encryption. The encrypted string in iOS is different as compared to Android.

Below is android code :

public class Encryption {
    private static final String ALGORITHM = "AES";
    private static final String UNICODE_FORMAT = "UTF8";

    public static String encryptValue(String valueToEnc) {
        try {
            Key key = generateKey();
            Cipher c = Cipher.getInstance(ALGORITHM);
            c.init(Cipher.ENCRYPT_MODE, key);
            byte[] encValue = c.doFinal(valueToEnc.getBytes());
            String encryptedValue = new Base64().encode(encValue);
            String urlEncodeddata = URLEncoder.encode(encryptedValue, "UTF-8");
            return urlEncodeddata;
        } catch (Exception e) {

        }
        return valueToEnc;
    }

    private static Key generateKey() throws Exception {
        byte[] keyAsBytes;
        keyAsBytes = "MySixteenCharKey".getBytes(UNICODE_FORMAT);
        Key key = new SecretKeySpec(keyAsBytes, ALGORITHM);
        return key;
    }
}

Answer 1

Create string extension and use library CryptoSwift

//  String+Addition.swift
import CryptoSwift
extension String {
func aesEncrypt(key: String) throws -> String {

        var result = ""

        do {

            let key: [UInt8] = Array(key.utf8) as [UInt8]

            let aes = try! AES(key: key, blockMode: ECB() , padding:.pkcs5) // AES128 .ECB pkcs7

            let encrypted = try aes.encrypt(Array(self.utf8))

            result = encrypted.toBase64()!


            print("AES Encryption Result: \(result)")

        } catch {

            print("Error: \(error)")
        }

        return result
    }
}

and to use

@IBAction func onBtnClicked(_ sender: Any) { 
        let value = "My value to be encrypted"
        let key = "MySixteenCharKey"

        print(key!)
        let encryptedValue = try! value.aesEncrypt(key: key!)

        print(encryptedValue)

    }

For citation of this particular android code: 1) The 16 char length key implies AES-128 2) The code is without iVector, This implies ECB mode 3) Using padding as pkcs5 or pkcs7 did not made any difference in my case

Answer 2

Create an extension of String and use this below function for encrypting and decrypting.

extension String {

//MARK: - Encrypt AES Method
/// This method will encrypt and return Cipher string

func aesEncrypt(key: String = "fqJfdzGDvfwbedsKSUGty3VZ9taXxMVw", iv: String = "1234567890123456") -> String {
    if let data = self.data(using: String.Encoding.utf8) {
        do {
            let enc = try AES(key: key, iv: iv, blockMode: .CBC, padding: PKCS7()).encrypt(data.bytes)
            let encData = Data(bytes: enc, count: Int(enc.count))
            let base64String: String = encData.base64EncodedString(options: NSData.Base64EncodingOptions(rawValue: 0));
            return base64String
        }
        catch let error {
            print(error.localizedDescription)
            return ""
        }
    }
    return ""
}

//MARK: - Decrypt AES Method
/// This method will decrypt the Cipher string

func aesDecrypt(key: String = "fqJfdzGDvfwbedsKSUGty3VZ9taXxMVw", iv: String = "1234567890123456") -> String {
    if let data = Data(base64Encoded: self, options: Data.Base64DecodingOptions.init(rawValue: 0)) {
        do {
            let dec = try AES(key: key, iv: iv, blockMode: .CBC, padding: PKCS7()).decrypt(data.bytes)
            let decData = Data(bytes: dec, count: Int(dec.count))
            let result = String(data: decData, encoding: .utf8)
            return result ?? ""
        }
        catch let error {
            print(error.localizedDescription)
            return ""
        }
    }

    return ""
    }
}

Answer 3

Please use below library for AES encryption and decryption. It is available for iOS, Android and Web as well.

Reference URL

For iOS

OS / Swift 3, 4

Add a bridging header. Apple documentation

#import "CryptLib.h"

let plainText = "this is my plain text"
let key = "your key"

let cryptLib = CryptLib()

let cipherText = cryptLib.encryptPlainTextRandomIV(withPlainText: plainText, key: key)
print("cipherText \(cipherText! as String)")

let decryptedString = cryptLib.decryptCipherTextRandomIV(withCipherText: cipherText, key: key)
print("decryptedString \(decryptedString! as String)")

Android

val plainText = "this is my plain text"
val key = "your key"

val cryptLib = CryptLib()

val cipherText = cryptLib.encryptPlainTextWithRandomIV(plainText, key)
println("cipherText $cipherText")

val decryptedString = cryptLib.decryptCipherTextWithRandomIV(cipherText, key)
println("decryptedString $decryptedString")

avascript / NodeJS / Web

Download the library

npm install @skavinvarnan/cryptlib --save

const plainText = "this is my plain text";
const key = "your key";

const cryptLib = require('@skavinvarnan/cryptlib');

const cipherText = cryptLib.encryptPlainTextWithRandomIV(plainText, key);
console.log('cipherText %s', cipherText);

const decryptedString = cryptLib.decryptCipherTextWithRandomIV(cipherText, key);
console.log('decryptedString %s', decryptedString);

You will get same encryption and decryption result for all plateform ioS/Android/Web.

Answer 4

Try this:

func encryptValue(stringToEncrypt:String) -> String{

    var encryptedString: String = ""

    let value = "MySixteenCharKey"
    let input: Array<UInt8> = Array(stringToEncrypt.utf8)
    let key: Array<UInt8> = Array("MySixteenCharKey".utf8)

    do {
        let encrypted = try AES(key: key, blockMode: .ECB, padding: PKCS7()).encrypt(input)
        let base64 = encrypted.toBase64()
        encryptedString = base64
    } catch {
        print(error)
    }

    return encryptedString
}