ios - How to decrypt a very long string of AES 256 (CBC) encryption in Flutter?

Question

I want to decrypt a very long base64 string of an encrypted JSON file, in which I'm provided with key and iv. And I'm not using the default PKCS7 padding instead I'm keeping the padding null in the encryption part. AES 256 encryption is of CBC mode.

With the help of "encrypt" dart package. I've tried decoding it, but the speed was very, very slow. But the solution I tried was natively configured respectively on Android & iOS, but It wasn't working on that long base64 encrypted string.

//This is some native code I wrote for iOS (Objective-C)


(NSString *)decrypt:(NSString *)text {
    NSString *result = 
      [text stringByTrimmingCharactersInSet:
      [NSCharacterSet whitespaceAndNewlineCharacterSet]];
    NSData *decodedBase64Data = [[NSData alloc] 
      initWithBase64EncodedString:result options:0]; //Decode Base64
    NSData *decodedAESData = [decodedBase64Data 
      AES256DecryptedDataWithKey:rd_key iv:rd_iv]; //Decode AES 256
    result = [[NSString alloc] initWithData:decodedAESData 
    encoding:NSUTF8StringEncoding];
    return result;
}

Is there any faster or a native solution to this problem? as I'm not able to decrypt the whole base64 encrypted string.

Base64 encypted String = "...2Btn9j6DjFOFgN2gUgVWv8!2FE94hmTZqge6wFMWCMBwRKu!
2BhaUSbip!2Brxa0tF5JqzVukbz4cbWZE6NGNgrA5BAeNHh3RVFBuoOG!2F!2Fiw!2BmsUob4W5ab9
P0lnHhPU9hk2qlfbj1ydS6m9OYYFwl!2F1QXAJ2I6lVZ81HYzeupP42!2BxqIx3zyURHZwQsCuOZ!
2BYits!2FqBC!2BSvAfiCUCeEOSqaAaLjbxXNAaIrtHRh3B9boAPESTxTKzUSC!2Bhpa72xk7
Dby8cl0MlflPAc9P2ihO3SD5GNVm9HWIjMga41OUvw1xMsgqqe5G5YnsNOom57cnLkj
JJhxsnfgnqaKxpAK0fdsov3f6!2FRDAVrSQledg4PWpQpNw9PCmIpzvk6!2wCbHck8
OlJm!2Br7NI9FNTfhJ2YceXohNkAZPkWW!2F2j9egRHNhbZNxGZoFnVE!2FgP1Zyqd6R
8Ma3b!2BhqCCWT4ZoSXXals26jVtkCMU5NA!2FWfxi6LbbsukyS9ViNj3gP8eCUH1!2Fbq
nLWXRfN03yqDcjM9tTFvSjorbqvf0sI0Go7crwJGaX7ODB4C!2FWcZ8plUTmqTZI!2BNUE
QKlxvGd24Vf!2B!2Br5ZvzvcM3Ew3CEw4JM1IZb30mqFEgFAt8dv08fj!2FRsQYt8PfK!2
r0ucWIAXVNz0ZySX6lgSza0ZHMSot!2BpUzt0Ru8vUuALL1g5xoEgh1l4yyjs2Dmxz4mJ4
0PNxdvye1FIjY!...";

Decrypted data should be like this!

标签： iosobjective-cencryptionflutteraes