Generate same encrypted string AES/CBC/PKCS7Padding in Objective C, .net and Android

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I want to generate the same encrypted string in iOS, android in .net. I can generate same string android and in .net but different for Objective C.

Android code:

public static String encrypt(String key, String value) {
    try {
        SecretKey secretKey = new SecretKeySpec(key.getBytes(), "AES");
        AlgorithmParameterSpec iv = new IvParameterSpec(key.getBytes());
        Cipher cipher = Cipher.getInstance("AES/CBC/PKCS7Padding");
        cipher.init(Cipher.ENCRYPT_MODE, secretKey, iv);
        return new String(Base64.encode(cipher.doFinal(value.getBytes("UTF-8")), Base64.NO_WRAP));

    } catch (Exception e) {
        e.printStackTrace();
    }
    return null;
}

backend code

public Encryption(input: string): any {

return CryptoJS.AES.encrypt(CryptoJS.enc.Utf8.parse(input), this.Cryptokey,

{

    keySize: 128 / 8,

    iv: this.iv,

    mode: CryptoJS.mode.CBC,

    padding: CryptoJS.pad.Pkcs7

});

} and in Objective C code

- (NSData *)AES256EncryptWithKey:(NSString *)key

{

// 'key' should be 32 bytes for AES256, will be null-padded otherwise
char keyPtr[kCCKeySizeAES256+1]; // room for terminator (unused)
bzero(keyPtr, sizeof(keyPtr)); // fill with zeroes (for padding)

// fetch key data
[key getCString:keyPtr maxLength:sizeof(keyPtr) encoding:NSUTF8StringEncoding];

NSUInteger dataLength = [self length];

//See the doc: For block ciphers, the output size will always be less than or
//equal to the input size plus the size of one block.
//That's why we need to add the size of one block here
size_t bufferSize = dataLength + kCCBlockSizeAES128;
void *buffer = malloc(bufferSize);

size_t numBytesEncrypted = 0;
CCCryptorStatus cryptStatus = CCCrypt(kCCEncrypt, kCCAlgorithmAES128, kCCOptionPKCS7Padding,
                                      keyPtr, kCCKeySizeAES256,
                                      NULL /* initialization vector (optional) */,
                                      [self bytes], dataLength, /* input */
                                      buffer, bufferSize, /* output */
                                      &numBytesEncrypted);
if (cryptStatus == kCCSuccess) {
    //the returned NSData takes ownership of the buffer and will free it on deallocation
    return [NSData dataWithBytesNoCopy:buffer length:numBytesEncrypted];
}

free(buffer); //free the buffer;
return nil;

}

and I followed these URLs Encrypt AES/CBC/PKCS7Padding

How to encrypt with AES 256 CBC in Objective C

AES CBC Encryption With PKCS7Padding Has Different Results In Java And Objective-C

As per my understanding for Objective C first I need to convert the password in NSData then pass it to the AES encryption method. This method will return to me encrypted Data now I need to convert this in base 64 string encoding. Can anyone suggest to me what should I do to generate the same result for iOS, Android, and .net?

For example if I want to encrypt string "xceedancce" in all 3 platforms and my key is 7061737323313233

then in Android and .net the result is "uXDlYA4e8Z8HWd9rvNdXaw==" same but in iOS

it is "l4zDDnwOVJ0dz2fl7HdKIA==" Can anyone suggest what should I do in Objective C?

Thank you.

objective-c encryption android ios
1 Answers

Thank you, Rob. I used the RNCryptor library for both (Objective C and C#) and it solved my problem.

Here is my code for Objective C:

-(NSString *)encryptUsingRNCryptor:(NSString *)strPassword{

NSData *data = [strPassword dataUsingEncoding:NSUTF8StringEncoding];
NSError *error;
NSData *encryptedData = [RNEncryptor encryptData:data
                                    withSettings:kRNCryptorAES256Settings
                                          password:kKeyForEncryption
                                             error:&error];
NSString *encryptString = [encryptedData base64EncodedStringWithOptions:0];

NSLog(@"enccrypted data ----->>>## %@ ## %@", encryptedData, encryptString);

// Decryption

NSData *decryptedData = [RNDecryptor decryptData:encryptedData
                                    withPassword:kKeyForEncryption
                                           error:&error];
NSString *decodedString = [[NSString alloc] initWithData:decryptedData encoding:NSUTF8StringEncoding];

NSLog(@" Decryted data ----%@ --------and string %@", decryptedData, decodedString);

return [encryptedData base64EncodedStringWithOptions:0];

}

and for C# decryption we used RNCryptor-cs library.

Once again thank you Rob :)

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