How to encrypt the NSString in ios locally

Question

I am working on the static application that means no webservices. My application contains activation page so that we need to enter text inside that textfield to validate.

if([textfield.text isEqualToString:@"AKS_BI"]) {
     //loading home screen
 } else {
//show alert
 }

For this one, I would like to encrypt the "AKS_BI" in order to hide the string while reverse engineering or Mat testing.

Can you anyone help me on this.

first decide which encryption method you want ?. refer this link for AES encryption. http://stackoverflow.com/questions/1400246/aes-encryption-for-an-nsstring-on-the-iphone — Rince Thomas, Feb 10 '16 at 08:32
This just moves the problem from keeping "AKS_BI" secret to keeping the encryption key secret. Who are you protecting the key from, the user or someone else? — zaph, Feb 10 '16 at 18:29

Satish A · Answer 1 · 2016-02-10T09:36:53.277

1

To encrypt:

//for best practise encrypting string length must be >=8
NSString *yourString=@"abcdefghij";

NSString *YourPasswordString = @"123456";//i've took static but you can set it dynamically
NSString *encryptPassword;

//Encrypt    
NSData *data = [YourPasswordString dataUsingEncoding: NSASCIIStringEncoding];
NSData *encryptedData = [data AESEncryptWithPassphrase:yourString];

//Encode Base 64    
[Base64 initialize];
encryptPassword = [Base64 encode:encryptedData];

For more details you can check here

Hope this helps.

edited Feb 10 '16 at 09:36

answered Feb 10 '16 at 08:41

Satish A

584
4
17

1

Are you sure that this method AESEncryptWithPassphrase is available without importing third party libraries ? – Andrea Feb 10 '16 at 08:52
NSString *yourString=@"abcdefghij"; At the time of reverse engineering and Math testing they can find this key right. – Sai Bharath Yadav Feb 10 '16 at 09:18
No. To find the key you need password for that. It's password protected encryption. – Satish A Feb 10 '16 at 09:42

score 0 · Answer 2 · answered Feb 10 '16 at 08:40

0

You can use this library https://github.com/RNCryptor/RNCryptor.

However, you will still need to store the encryption key securely. For that I would recommend to split them up and perform some operation on them to combine.

answered Feb 10 '16 at 08:40

John Bennedict Lorenzo

527
3
10

This has just moved the problem, might as well use the advice for the encryption key for "AKS_BI". – zaph Feb 10 '16 at 18:27

score -1 · Accepted Answer · answered Feb 10 '16 at 12:57

Download AES encryption files from github. Download from here

After adding these downloaded files in your project now compare ,

       if ([[AESCrypt encrypt:textfield.text password:[[NSBundle mainBundle] bundleIdentifier]] isEqualToString:ACTIVATION_STRING])

Here, ACTIVATION_STRING = hYjhuOO+GYTUBS05== .... This encrypted string needs to be created with the below syntax and make sure that remove the below syntax from code after generation of encrypted string,
```
   NSString *encryptedData = [AESCrypt encrypt:@"AKS_BI" password: [[NSBundle mainBundle] bundleIdentifier]];
```

That's it. It simple.

Thanks a lot. I have already downloaded these files. Now its working fine as expected. — Sai Bharath Yadav, Feb 10 '16 at 13:05

How to encrypt the NSString in ios locally

3 Answers3