générer des AES 256 bits valeur de la clé de

Vous pouvez construire le Rfc2898DeriveBytes Classe avec un arbitraire de la taille d'un mot de passe et ensuite dériver une clé de la taille désirée dans ce cas, 256 bits (32 octets):

private static byte[] CreateKey(string password, int keyBytes = 32)
{
    const int Iterations = 300;
    var keyGenerator = new Rfc2898DeriveBytes(password, Salt, Iterations);
    return keyGenerator.GetBytes(keyBytes);
}

Afin de produire un déterministe de sortie (c'est à dire même entrée produira le même résultat), vous devrez coder en dur le sel. Le sel doit être d'au moins 8 octets:

private static readonly byte[] Salt = 
    new byte[] { 10, 20, 30 , 40, 50, 60, 70, 80};

public static string GenerateBitKey(int letterCount = 44)
    {
        //Get the number of words and letters per word.
        int num_letters = letterCount;
        //Make an array of the letters we will use.
        char[] letters = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789".ToCharArray();

        //Make a random number generator.
        Random rand = new Random();

        //Make the words.
        //Make a word.
        string word = "";
        for (int j = 1; j <= num_letters; j++)
        {
            //Pick a random number between 0 and 25
            //to select a letter from the letters array.
            int letter_num = rand.Next(0, letters.Length - 1);

            //Append the letter.
            word += letters[letter_num];
        }
        return word;
    }

Ma version. Je voulais juste clés sans un mot de passe.

    public static string GenerateBitKey(int letterCount = 44)
{
//Get the number of words and letters per word.
int num_letters = letterCount;
//Make an array of the letters we will use.
char[] letters = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789abcdefghijklmnopqrsruvwxyz+".ToCharArray();
int lettersLength =  letters.Length;
//Make a word.
string word = "";
//Use Cryptography to generate random numbers rather than Psuedo Random Rand
//Deliberate overkill here
byte[] randomBytes = new byte[num_letters*256];
List<int> rands = new List<int>();
do
{
using (System.Security.Cryptography.RNGCryptoServiceProvider rngCsp = new
System.Security.Cryptography.RNGCryptoServiceProvider())
{
//Fill the array with a random value.
rngCsp.GetBytes(randomBytes);
}
//Truncate the set of random bytes to being in range 0 .. (lettersLength-1)
//Nb Using mod of randomBytes will reduce entropy of the set
foreach (var x in randomBytes)
{
if (x < lettersLength)
rands.Add((int)x);
if (rands.Count()==num_letters)
break;
}
}
while (rands.Count < letterCount);
int[] randsArray = rands.ToArray();
//Get random selection of characters from letters
for (int j = 0; j < num_letters; j++)
{
int letter_num = randsArray[j];
//Append the letter.
word += letters[letter_num];
}
return word;
}