C# Can’t generate initialization vector IV

ccryptographyencryptioninitialization-vector

I get the following error when I try to create a IV initialization vector for TripleDES encryptor.

Please see the code example:

TripleDESCryptoServiceProvider tripDES = new TripleDESCryptoServiceProvider();

byte[] key = Encoding.ASCII.GetBytes("SomeKey132123ABC");
byte[] v4 = key;
byte[] connectionString = Encoding.ASCII.GetBytes("SomeConnectionStringValue");
byte[] encryptedConnectionString = Encoding.ASCII.GetBytes("");

// Read the key and convert it to byte stream
tripDES.Key = key; 
tripDES.IV = v4;

This is the exception that I get from the VS.

Specified initialization vector (IV) does not match the block size for this algorithm.

Where am I going wrong?

Thank you

Best Answer

MSDN explicitly states that:

...The size of the IV property must be the same as the BlockSize property.

For Triple DES it is 64 bits.

Related Solutions

C# – Specified initialization vector (IV) does not match the block size for this algorithm

The problem is your initialization vector size needs to be 16 bytes.

Your initial vector size is 14 bytes.

You will need to increase the size of your initial vector by 2 bytes and your code will work.

Example:

string initVector = "HR$2pIjHR$2pIj12";

You will then get the output with your current code and the example IV (initialization vector) size provided:

hAC8hMf3N5Zb/DZhFKi6Sg==

This article provides a good explanation on what the initialization vector is.

http://en.wikipedia.org/wiki/Initialization_vector

C# – How to generate random alphanumeric strings

I heard LINQ is the new black, so here's my attempt using LINQ:

private static Random random = new Random();
public static string RandomString(int length)
{
    const string chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
    return new string(Enumerable.Repeat(chars, length)
      .Select(s => s[random.Next(s.Length)]).ToArray());
}

(Note: The use of the Random class makes this unsuitable for anything security related, such as creating passwords or tokens. Use the RNGCryptoServiceProvider class if you need a strong random number generator.)

Best Answer

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C# – Specified initialization vector (IV) does not match the block size for this algorithm

C# – How to generate random alphanumeric strings

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