> HI, im trying to get a string hashed, im trying to use the example:
> http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnnet
> sec/html/cryptosimplified.asp
>
> my problem is that even if i have a string that is 20 characters long
> and a salt that is 80 characters, the output is still only like
> 15characters, i am trying to get a hash output that is atleast
> 100characters long.
>
> i have tried to alter the code alittle to see if i could get a longer
> hash returned, but sofar nothing.
>
> private HashAlgorithm mhash;
>
> private void cmdHash_Click (object sender, System.EventArgs e)
> {
> string temp = string.Empty;
> txtSalt.Text = CreateSalt();
> temp = txtOriginal.Text + txtSalt.Text.Substring(8, 70);
> txtHashed.Text = HashString(temp, txtSalt.Text);
> }
>
> private string CreateSalt ()
> {
> byte[] bytSalt = new byte[80];
> RNGCryptoServiceProvider rng;
> rng = new RNGCryptoServiceProvider();
>
> rng.GetBytes(bytSalt);
>
> return Convert.ToBase64String(bytSalt);
> }
> private string HashString(string Value, string salt)
> {
> byte[] bytValue;
> byte[] bytHash;
> mhash = HMACSHA1(Convert.FromBase64String(salt));
>
> // Convert the original string to array of Bytes
> bytValue = System.Text.Encoding.UTF8.GetBytes(Value);
> // Compute the Hash, returns an array of Bytes
> bytHash = mhash.ComputeHash(bytValue);
> mhash.Clear();
>
> // Return a base 64 encoded string of the Hash value
> return Convert.ToBase64String(bytHash);
> }

"Dominick Baier [DevelopMentor]" wrote:

> Hi,
>
> using HMACxxx is the wrong approach - or do you want to encrypt the hash?
>
> Different hashing algorithm produce different output lengthts
>
> SHA1 = 160bits
> SHA256 = 256bits
> SHA512 = 512bits
>
> simply use them like this:
>
> SHA256Managed sha = new SHA256Manager()
>
> byte[] hash = sha.ComputeHash(data);
>
> if you want flexible output lengths (or maybe you are hashing passwords??)
>
> use PasswordDeriveBytes (1.1) or better Rfc2898DeriveBytes (2.0)
>
> ---------------------------------------
> Dominick Baier - DevelopMentor
> http://www.leastprivilege.com
>
> > HI, im trying to get a string hashed, im trying to use the example:
> > http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnnet
> > sec/html/cryptosimplified.asp
> >
> > my problem is that even if i have a string that is 20 characters long
> > and a salt that is 80 characters, the output is still only like
> > 15characters, i am trying to get a hash output that is atleast
> > 100characters long.
> >
> > i have tried to alter the code alittle to see if i could get a longer
> > hash returned, but sofar nothing.
> >
> > private HashAlgorithm mhash;
> >
> > private void cmdHash_Click (object sender, System.EventArgs e)
> > {
> > string temp = string.Empty;
> > txtSalt.Text = CreateSalt();
> > temp = txtOriginal.Text + txtSalt.Text.Substring(8, 70);
> > txtHashed.Text = HashString(temp, txtSalt.Text);
> > }
> >
> > private string CreateSalt ()
> > {
> > byte[] bytSalt = new byte[80];
> > RNGCryptoServiceProvider rng;
> > rng = new RNGCryptoServiceProvider();
> >
> > rng.GetBytes(bytSalt);
> >
> > return Convert.ToBase64String(bytSalt);
> > }
> > private string HashString(string Value, string salt)
> > {
> > byte[] bytValue;
> > byte[] bytHash;
> > mhash = HMACSHA1(Convert.FromBase64String(salt));
> >
> > // Convert the original string to array of Bytes
> > bytValue = System.Text.Encoding.UTF8.GetBytes(Value);
> > // Compute the Hash, returns an array of Bytes
> > bytHash = mhash.ComputeHash(bytValue);
> > mhash.Clear();
> >
> > // Return a base 64 encoded string of the Hash value
> > return Convert.ToBase64String(bytHash);
> > }
>
>
>