AES/CBC/PKCS5Padding in iOS objective c result differs from Android

Question

I am using the AES/CBC/PKCS5Padding in Android application. Code is like-

    private static String TRANSFORMATION = "AES/CBC/PKCS5Padding";

    private static String ALGORITHM = "AES";
    private static String DIGEST = "MD5";

    private static Cipher cipher;
    private static SecretKey password;
    private static IvParameterSpec IVParamSpec;
    private final static String pvtkey="GDNBCGDRFSC$%#%=";

    //16-byte private key
    private static byte[] IV = pvtkey.getBytes();

    public PassWordEncryptor() {
        try {

            //Encode digest
            MessageDigest digest;           
            digest = MessageDigest.getInstance(DIGEST);            
            password = new SecretKeySpec(digest.digest(pvtkey.getBytes()), ALGORITHM);

            //Initialize objects
            cipher = Cipher.getInstance(TRANSFORMATION);
            IVParamSpec = new IvParameterSpec(IV);

        } catch (NoSuchAlgorithmException e) {
            Log.i(Lams4gApp.TAG, "No such algorithm " + ALGORITHM);
        } catch (NoSuchPaddingException e) {
            System.out.println( "No such padding PKCS7"+ e);
        }
    }
    /**
    Encryptor.

    @text String to be encrypted
    @return Base64 encrypted text

    */
    public String encrypt(byte[] text) {

        byte[] encryptedData;

        try {

            cipher.init(Cipher.ENCRYPT_MODE, password, IVParamSpec);
            encryptedData = cipher.doFinal(text);

        } catch (InvalidKeyException e) {
            System.out.println( "Invalid key  (invalid encoding, wrong length, uninitialized, etc)."+ e);
            return null;
        } catch (InvalidAlgorithmParameterException e) {
            System.out.println( "Invalid or inappropriate algorithm parameters for " + ALGORITHM+ e);
            return null;
        } catch (IllegalBlockSizeException e) {
            System.out.println( "The length of data provided to a block cipher is incorrect"+ e);
            return null;
        } catch (BadPaddingException e) {
            System.out.println( "The input data but the data is not padded properly."+ e);
            return null;
        }               
        return Base64.encodeToString(encryptedData,Base64.DEFAULT);

    }

I need similar code in iOS Objective C. Encryption and Decryption results should be same in android and iOS. Kindly provide the same algorithm for Objective C.

I am using iOS code as-

- (void)viewDidLoad {
    [super viewDidLoad];

    NSData *encodingData=[self encrypt:[@"slapkh"
                                          dataUsingEncoding:NSUTF8StringEncoding]];
    NSString *encodingResult = [NSString base64StringFromData:encodingData length:[encodingData length]];


}

- (NSData *) encrypt:(NSData *) plainText {
            return [self transform:kCCEncrypt data:plainText];
}

- (NSData *) decrypt:(NSData *) cipherText {
            return [self transform:kCCDecrypt data:cipherText];
}
- (NSData *) transform:(CCOperation) encryptOrDecrypt data:(NSData *) inputData {
     Cipher* cipher = [[Cipher alloc]initWithKey:@"GDNBCGDRFSC$%#%="];
    NSString* Key = cipher.cipherKey;

    // kCCKeySizeAES128 = 16 bytes
   // CC_MD5_DIGEST_LENGTH = 16 bytes
   NSData* secretKey = [Cipher md5:Key];

   CCCryptorRef cryptor = NULL;
   CCCryptorStatus status = kCCSuccess;

   uint8_t iv[kCCBlockSizeAES128];
   memset((void *) iv, 0x0, (size_t) sizeof(iv));

   status = CCCryptorCreate(encryptOrDecrypt,
                            kCCAlgorithmAES128,kCCOptionPKCS7Padding,
                            [secretKey bytes], kCCKeySizeAES128, iv, &cryptor);

   if (status != kCCSuccess) {
       return nil;
   }

   size_t bufsize = CCCryptorGetOutputLength(cryptor, (size_t)[inputData length],
                                             true);

   void * buf = malloc(bufsize * sizeof(uint8_t));
   memset(buf, 0x0, bufsize);

      size_t bufused = 0;
      size_t bytesTotal = 0;

      status = CCCryptorUpdate(cryptor, [inputData bytes], (size_t)[inputData length],
                               buf, bufsize, &bufused);

      if (status != kCCSuccess) {
          free(buf);
          CCCryptorRelease(cryptor);
          return nil;
      }

      bytesTotal += bufused;

      status = CCCryptorFinal(cryptor, buf + bufused, bufsize - bufused, &bufused);

      if (status != kCCSuccess) {
          free(buf);
          CCCryptorRelease(cryptor);
          return nil;
      }

      bytesTotal += bufused;

      CCCryptorRelease(cryptor);

      return [NSData dataWithBytesNoCopy:buf length:bytesTotal];
  }

But the results for Android and iOS Differs as- Text to encrypt: slapkh key: GDNBCGDRFSC$%#%=

Android result: jN2p1yAdBJLRmoHq+k9KtA==\n

iOS Resut: tbaSJFv5mGyZ9t/+kOw+gg==

Answer 1

After spending time dealing with this, I got success in ANDROID(java) and IOS (Objc) using AES with the codes below:

ANDROID CODE

    import java.io.IOException;
    import java.security.InvalidAlgorithmParameterException;
    import java.security.InvalidKeyException;
    import java.security.NoSuchAlgorithmException;

    import javax.crypto.BadPaddingException;
    import javax.crypto.Cipher;
    import javax.crypto.IllegalBlockSizeException;
    import javax.crypto.NoSuchPaddingException;
    import javax.crypto.spec.IvParameterSpec;
    import javax.crypto.spec.SecretKeySpec;

    public class SecurityUtils {

        private static final String ALGORITHM = "AES";
        private static final String MODE = "AES";
        private static final String IV = "AEE0715D0778A4E4";
        private static final String KEY= "9336365521W5F092BB5909E8E033BC69";

        public static  String encrypt(String value ) throws NoSuchPaddingException, NoSuchAlgorithmException, BadPaddingException, IllegalBlockSizeException, InvalidAlgorithmParameterException, InvalidKeyException {
            SecretKeySpec secretKeySpec = new SecretKeySpec(KEY.getBytes(), ALGORITHM);
            Cipher cipher = Cipher.getInstance(MODE);
            cipher.init(Cipher.ENCRYPT_MODE, secretKeySpec, new IvParameterSpec(IV.getBytes()));
            byte[] values = cipher.doFinal(value.getBytes());
            return Base64.encodeBytes(values);
        }

        public static  String decrypt(String value) throws IOException, NoSuchPaddingException, NoSuchAlgorithmException, BadPaddingException, IllegalBlockSizeException, InvalidAlgorithmParameterException, InvalidKeyException {
            byte[] values = Base64.decode(value);
            SecretKeySpec secretKeySpec = new SecretKeySpec(KEY.getBytes(), ALGORITHM);
            Cipher cipher = Cipher.getInstance(MODE);
            cipher.init(Cipher.DECRYPT_MODE, secretKeySpec, new IvParameterSpec(IV.getBytes()));
            return new String(cipher.doFinal(values));
        }
    }

TESTING ANDROID

   try {
        String encrypted = SecurityUtils.encrypt("My Secret Text");
        String decrypted = SecurityUtils.decrypt(encrypted);
        Log.e("encrypted", encrypted);
        Log.e("decrypted", decrypted);
    }catch(Exception ex){
        Log.e("AES", ex.getMessage());
    }

IOS CODE

Header file

#import <Foundation/Foundation.h>
#import <CommonCrypto/CommonCryptor.h>

NS_ASSUME_NONNULL_BEGIN

@interface SecurityUtils : NSObject

+ (NSString *)encrypt:(NSString *)plainText error:(NSError **)error;
+ (NSString *)decrypt:(NSString *)plainText error:(NSError **)error;

@end

NS_ASSUME_NONNULL_END

Implementation file

NSString *const IV = @"AEE0515D0B08A4E4";
NSString *const KEY =  @"9336565521E5F082BB5929E8E033BC69";


#import "SecurityUtils.h"


@implementation SecurityUtils


+ (NSString *)encrypt:(NSString *)plainText error:(NSError **)error {
    NSMutableData *result =  [SecurityUtils doAES:[plainText dataUsingEncoding:NSUTF8StringEncoding] context: kCCEncrypt error:error];
    return [result base64EncodedStringWithOptions:0];
}


+ (NSString *)decrypt:(NSString *)encryptedBase64String error:(NSError **)error {
    NSData *dataToDecrypt = [[NSData alloc] initWithBase64EncodedString:encryptedBase64String options:0];
    NSMutableData *result = [SecurityUtils doAES:dataToDecrypt context: kCCDecrypt error:error];
    return [[NSString alloc] initWithData:result encoding:NSUTF8StringEncoding];
    
}

+ (NSMutableData *)doAES:(NSData *)dataIn context:(CCOperation)kCCEncrypt_or_kCCDecrypt error:(NSError **)error {
        CCCryptorStatus ccStatus   = kCCSuccess;
        size_t          cryptBytes = 0;
        NSMutableData  *dataOut    = [NSMutableData dataWithLength:dataIn.length + kCCBlockSizeBlowfish];
        NSData *key =[KEY dataUsingEncoding:NSUTF8StringEncoding];
        NSData *iv = [IV dataUsingEncoding:NSUTF8StringEncoding];
        
        ccStatus = CCCrypt( kCCEncrypt_or_kCCDecrypt,
                           kCCAlgorithmAES,
                           kCCOptionPKCS7Padding,
                           key.bytes,
                           key.length,
                           (iv)?nil:iv.bytes,
                           dataIn.bytes,
                           dataIn.length,
                           dataOut.mutableBytes,
                           dataOut.length,
                           &cryptBytes);
        
        if (ccStatus == kCCSuccess) {
            dataOut.length = cryptBytes;
        }
        else {
            if (error) {
                *error = [NSError errorWithDomain:@"kEncryptionError"
                                             code:ccStatus
                                         userInfo:nil];
            }
            dataOut = nil;
        }
        
        return dataOut;
}


@end

IOS TESTING

NSError *error;
NSString *encrypted = [SecurityUtils encrypt:@"My Secret Text" error:&error];
NSLog(@"encrypted: %@",encrypted);
NSLog(@"decrypted: %@",[SecurityUtils decrypt:encrypted error:&error]);

Finally, the outputs of the test:

ANDROID OUTPUT

2019-05-16 21:35:01.215 4920-4920/br.com.my.app E/encrypted: EJ41am5W1k6fA7ygFjTSEw==
2019-05-16 21:35:01.215 4920-4920/br.com.my.app E/decrypted: My Secret Text

IOS OUTPUT

2019-05-16 21:38:02.947043-0300 MyApp[63392:1590665] encrypted: EJ41am5W1k6fA7ygFjTSEw==
2019-05-16 21:38:02.947270-0300 MyApp[63392:1590665] decrypted: My Secret Text

My repo on GitHub with this example.