Re: MD5

From: Dominick Baier [DevelopMentor] (dbaier_at_pleasepleasenospamdevelop.com)
Date: 11/22/05


Date: Tue, 22 Nov 2005 07:07:07 -0800

Hello Marre,

so far you are only doing

MD5(inputvalue)

is that what you want??

---------------------------------------
Dominick Baier - DevelopMentor
http://www.leastprivilege.com

> Hi Dominick!
>
> Thanks for youre answer. Now I get a string, but I canīt get that
> string equal with the string I receive :) I have to try it a little
> bit more. My code looks like this:
>
> private string checkMD5sum(string inputvalue)
> {
> // Perform a hash operation using the phrase. This will
> // generate a unique 32 character value to be used as the key.
> byte[] bytePhrase = Encoding.Default.GetBytes(inputvalue);
> MD5 md5 = new MD5CryptoServiceProvider();
> md5.ComputeHash(bytePhrase);
> byte[] result = md5.Hash;
> // Build the final string by converting each byte
> // into hex and appending it to a StringBuilder
> StringBuilder sb = new StringBuilder();
> for (int i=0;i<result.Length;i++)
> {
> sb.Append(result[i].ToString("X2"));
> }
> // And return it
> return sb.ToString();
> }
> Best regards
> Marre
> "Dominick Baier [DevelopMentor]"
> <dbaier@pleasepleasenospamdevelop.com> wrote in message
> news:4580be631481398c7bd799da46c07@news.microsoft.com...
>
>> Hello Marre,
>>
>> this uses SHA1 for something similar - should be enough to get you
>> started...
>>
>> // Hash = H(salt, H(passphrase))
>> static void lengthExtensionHash2()
>> {
>> Console.WriteLine("Hash with anti length extension attack 2");
>> string password = "secret";
>> byte[] passwordBytes = Encoding.Unicode.GetBytes(password);
>> byte[] salt = new byte[32];
>> new RNGCryptoServiceProvider().GetBytes(salt);
>>
>> SHA1Managed sha = new SHA1Managed();
>>
>> byte[] hashedPasswordBytes = sha.ComputeHash(passwordBytes);
>>
>> CryptoStream cs = new CryptoStream(Stream.Null, sha,
>> CryptoStreamMode.Write);
>> cs.Write(salt, 0, salt.Length);
>> cs.Write(hashedPasswordBytes, 0, hashedPasswordBytes.Length);
>> cs.FlushFinalBlock();
>> byte[] hash = sha.Hash;
>>
>> string hashString = Convert.ToBase64String(hash);
>> string saltString = Convert.ToBase64String(salt);
>> Console.WriteLine("Hash: " + hashString);
>> Console.WriteLine("Salt: " + saltString);
>> }
>> ---------------------------------------
>> Dominick Baier - DevelopMentor
>> http://www.leastprivilege.com
>>> Hi all!
>>>
>>> I have a md5 question.
>>> I receive a md5 string created with Message-Digest algorithm and I
>>> want to
>>> create the same string in my webapplication.
>>> I have this values to go on:
>>> myMD5String = MD5(mySecretValue2 + MD5(mySecretValue1 + "some
>>> string"))
>>>
>>> myMD5String should of cource be the same as the md5 string i
>>> receive.
>>>
>>> I have no idea if I have told you enough about my problem, but
>>> someone might be able to point me to right direction :)
>>>
>>> Best regards
>>> Marre