Facing problem while decryption in iphone5

[shwetalodhe]

Hi,
I am using this code of AES256 encryption in iphone app.This giving expected output in all device higher than iphone5 simualator(version 10.0). While converting the encrypted NSdata to nsstring using NSUTF8StringEncoding its returning nil nsstring.Unable to understand reason.Can anyone help on this.
Also find the code which i am using for conversion

NSString *cipherText =@"1xZKEyLmVzKDoA+2+G2xiA==";
NSString *ivRandom = @"54327CD65463ECAB";
NSString *key = @"B98MN8C9A8765BCA";
NSData *nsdataFromBase64String = [[NSData alloc]
initWithBase64EncodedString:cipherText options:0];

NSData *dataDecrypt = [cryptoLib decrypt:nsdataFromBase64String key:key iv:ivRandom];
NSString *base64Decoded = [[NSString alloc]
                           initWithData:dataDecrypt encoding:NSUTF8StringEncoding];