Develop Reference

How can I output arbitrary binary data as character representation in C#?

I'm trying to recreate the functionallity of
slappasswd -h {md5}
on .Net
I have this code on Perl
use Digest::MD5;
use MIME::Base64;
$ctx = Digest::MD5->new;
$ctx->add('fredy');
print "Line $.: ", $ctx->clone->hexdigest, "\n";
print "Line $.: ", $ctx->digest, "\n";
$hashedPasswd = '{MD5}' . encode_base64($ctx->digest,'');
print $hashedPasswd . "\n";
I've tried to do the same on VB.Net , C# etc etc , but only works the
$ctx->clone->hexdigest # result : b89845d7eb5f8388e090fcc151d618c8
part in C# using the MSDN Sample
static string GetMd5Hash(MD5 md5Hash, string input)
{
// Convert the input string to a byte array and compute the hash.
byte[] data = md5Hash.ComputeHash(Encoding.UTF8.GetBytes(input));
// Create a new Stringbuilder to collect the bytes
// and create a string.
StringBuilder sBuilder = new StringBuilder();
// Loop through each byte of the hashed data
// and format each one as a hexadecimal string.
for (int i = 0; i < data.Length; i++)
{
sBuilder.Append(data[i].ToString("x2"));
}
// Return the hexadecimal string.
return sBuilder.ToString();
}
With this code in Console App :
string source = "fredy";
using (MD5 md5Hash = MD5.Create())
{
string hash = GetMd5Hash(md5Hash, source);
Console.WriteLine("The MD5 hash of " + source + " is: " + hash + ".");
}
outputs : The MD5 hash of fredy is: b89845d7eb5f8388e090fcc151d618c8.
but i need to implement the $ctx->digest function, it outputs some binary data like
¸˜E×ë_ƒˆàüÁQÖÈ
this output happens on Linux and Windows with Perl.
Any ideas?
Thanks

As I already said in my comment above, you are mixing some things up. What the digest in Perl creates is a set of bytes. When those are printed, Perl will convert them automatically to a string-representation, because (simplified) it thinks if you print stuff it goes to a screen and you want to be able to read it. C# does not do that. That doesn't mean the Perl digest and the C# digest are not the same. Just their representation is different.
You have already established that they are equal if you convert both of them to a hexadecimal representation.
Now what you need to do to get output in C# that looks like the string that Perl prints when you do this:
print $ctx->digest; # output: ¸˜E×ë_ƒˆàüÁQÖÈ
... is to convert the C# byte[] data to a string of characters.
That has been answered before,f or example here: How to convert byte[] to string?
Using that technique, I believe your function to get it would look like this. Please note I am a Perl developer and I have no means of testing this. Consider it C#-like pseudo-code.
static string GetMd5PerlishString(MD5 md5Hash, string input)
{
// Convert the input string to a byte array and compute the hash.
byte[] data = md5Hash.ComputeHash(Encoding.UTF8.GetBytes(input));
string result = System.Text.Encoding.UTF8.GetString(data);
return result;
}
Now it should look the same.
Please also note that MD5 is not a secure hashing algorithm for passwords any more. Please do not store use it to store user passwords!

Convert Hash256 String Result to Uppercase?

I'm trying to get a website Login page and a C# launcher to connect to a MySQL database, my C# code converts a string to SHA256 but in uppercase. So I figured it would be easier to change in PHP, so using strtoupper I pass the variable string for the encrypted password. It works great the only problem is this:
bec4c38f480db265e86e1650b1515216be5095f7a049852f76eea9934351b9ac - Original
BEC4C38F48DB265E86E1650B1515216BE5095F7A049852F76EEA9934351B9AC - C#
^ Right here there is meant to be a 0
I'm not sure what's gone wrong as both are using the exact same encryption method and it's odd that it's only one Character... Has anyone experienced this before?
PHP to encrypt text to SHA256 and then strtoupper:
$encrypt_password=(hash('sha256', $mypassword));
$s_password = strtoupper($encrypt_password);
C# Convert string to SHA256:
System.Security.Cryptography.SHA256 sha256 = new System.Security.Cryptography.SHA256Managed();
byte[] sha256Bytes = System.Text.Encoding.Default.GetBytes(txtpass.Text);
byte[] cryString = sha256.ComputeHash(sha256Bytes);
string sha256Str = string.Empty;
for (int i = 0; i < cryString.Length; i++)
{
sha256Str += cryString[i].ToString("X");
}
This is the only code that involves encrypting on both sides.

A value like 13 is just "D" not "0D" like would represented in the hash. You need to pad values that are less than 2 digits. Use "X2" as the format string.

Ignore Zero in Calculate Hash by HMACSHA256

I use Crypto-JS v2.5.3 (hmac.min.js) http://code.google.com/p/crypto-js/ library to calculate client side hash and the script is:
$("#PasswordHash").val(Crypto.HMAC(Crypto.SHA256, $("#pwd").val(), $("#PasswordSalt").val(), { asByte: true }));
this return something like this:
b3626b28c57ea7097b6107933c6e1f24f586cca63c00d9252d231c715d42e272
Then in Server side I use the following code to calculate hash:
private string CalcHash(string PlainText, string Salt) {
string result = "";
ASCIIEncoding enc = new ASCIIEncoding();
byte[]
baText2BeHashed = enc.GetBytes(PlainText),
baSalt = enc.GetBytes(Salt);
System.Security.Cryptography.HMACSHA256 hasher = new HMACSHA256(baSalt);
byte[] baHashedText = hasher.ComputeHash(baText2BeHashed);
result = string.Join("", baHashedText.ToList().Select(b => b.ToString("x")).ToArray());
return result;
}
and this method returned:
b3626b28c57ea797b617933c6e1f24f586cca63c0d9252d231c715d42e272
As you see there is just some zero characters that the server side method ignore that. where is the problem? is there any fault with my server side method? I just need this two value be same with equal string and salt.

As you see there is just some zero characters that the server side method ignore that. where is the problem?
Here - your conversion to hex in C#:
b => b.ToString("x")
If b is 10, that will just give "a" rather than "0a".
Personally I'd suggest a simpler hex conversion:
return BitConverter.ToString(baHashedText).Replace("-", "").ToLowerInvariant();
(You could just change "x" to "x2" instead, to specify a length of 2 characters, but it's still a somewhat roundabout way of performing a bytes-to-hex conversion.)

Everyone else keeps reccomending to use things like using BitConverter and trimming "-" or using ToString(x2). There is a better solution, a class that has been in .NET since 1.1 SoapHexBinary.
using System.Runtime.Remoting.Metadata.W3cXsd2001;
public byte[] StringToBytes(string value)
{
SoapHexBinary soapHexBinary = SoapHexBinary.Parse(value);
return soapHexBinary.Value;
}
public string BytesToString(byte[] value)
{
SoapHexBinary soapHexBinary = new SoapHexBinary(value);
return soapHexBinary.ToString();
}
This will produce the exact format you want.

I believe the problem is here:
result = string.Join("", baHashedText.ToList().Select(b => b.ToString("x")).ToArray());
change it to:
result = string.Join("", baHashedText.ToList().Select(b => b.ToString("x2")).ToArray());

Hashing non ascii characters C#

Here are two hash generators:
http://www.md5hashgenerator.com/index.php
http://www.miraclesalad.com/webtools/md5.php
Now, my question is:
Why do the hashes differ when trying to hash the char '€' (0x80)?
I assume it happens because '€' is not a normal ASCII character.
Which of the two hashes is 'correct'?
I'm trying to calculate the hash returned by hash generator 1 with C#.
This hashing function doesn't return it.
private string GetMD5Hash(string TextToHash)
{
if ((TextToHash == null) || (TextToHash.Length == 0))
{
return string.Empty;
}
MD5 md5 = new MD5CryptoServiceProvider();
byte[] textToHash = Encoding.Default.GetBytes(TextToHash);
byte[] result = md5.ComputeHash(textToHash);
return BitConverter.ToString(result).Replace("-", "").ToLower();
}
How could I change it so it returns the hash I want?
Additional Info:
I made a little AutoIt script:
#include <Crypt.au3>
ConsoleWrite(StringLower(StringMid(_Crypt_HashData(Chr(128), $CALG_MD5),3)) & #CRLF)
and it returns the hash I want!
However I need a C# code :)

It comes down to which encoding you use to turn the string into a byte[] (hence my suggestion to use try UTF-8, as that is a pretty common choice here; however, any full unicode encoding would work as long as you know which to use) ; for example, based on the string "abc€" we can deduce that the first site might be using any of:
874: Thai (Windows)
936: Chinese Simplified (GB2312)
1250: Central European (Windows)
1252: Western European (Windows)
1253: Greek (Windows)
1254: Turkish (Windows)
1255: Hebrew (Windows)
1256: Arabic (Windows)
1257: Baltic (Windows)
1258: Vietnamese (Windows)
50227: Chinese Simplified (ISO-2022)
51936: Chinese Simplified (EUC)
52936: Chinese Simplified (HZ)
Personally, I'd use UTF-8!
Here's the code I used to find the candidate encodings:
MD5 md5 = new MD5CryptoServiceProvider();
foreach (var enc in Encoding.GetEncodings())
{
byte[] textToHash = enc.GetEncoding().GetBytes("abc€");
byte[] result = md5.ComputeHash(textToHash);
var output = BitConverter.ToString(result).Replace("-", "").ToLower();
if(output == "7a66042043b2cc38ba16a13c596d740e")
{ // result from http://www.md5hashgenerator.com/index.php
Console.WriteLine(enc.CodePage + ": " + enc.DisplayName);
}
}
Further, testing with the string "dnos ʇǝqɐɥdʃɐ" shows that the second site is definitely using UTF-8; the first site finds no matches, so I guess it is using a code-page based encoding, and in short will not work reliably with the full range of unicode.

Both of the MD5 pages you've shown describe MD5 as an operation which works on strings. It isn't - it's an operation which works on byte sequences. In order to convert from a string to a byte sequence, you need to use an encoding.
You've chosen Encoding.Default which is almost always a bad choice - I'd generally choose Encoding.UTF8. However, importantly, neither of those sites say what they're using. However, in real life I would hope you'd either have control over both hashing processes (assuming there really are two) or that any hashing code you don't have control over will specify what encoding to use.
Note that there's a simpler way of creating an instance of MD5 - just use MD5.Create. You should also generally put it in a using statement as it implements IDisposable:
private static string GetMD5Hash(string text)
{
if (string.IsNullOrEmpty(text))
{
return "";
}
using (var md5 = MD5.Create())
{
byte[] hash = md5.ComputeHash(Encoding.UTF8.GetBytes(text));
return BitConverter.ToString(hash).Replace("-", "").ToLower();
}
}

Best way to decode hex sequence of unicode characters to string

I'm working with C# .Net
I would like to know how to convert a Unicode form string like "\u1D0EC"
(note that it's above "\uFFFF") to it's symbol... "𝃬"
Thanks For Advance!!!

That Unicode codepoint is encoded in UTF32. .NET and Windows encode Unicode in UTF16, you'll have to translate. UTF16 uses "surrogate pairs" to handle codepoints above 0xffff, a similar kind of approach as UTF8. The first code of the pair is 0xd800..dbff, the second code is 0xdc00..dfff. Try this sample code to see that at work:
using System;
using System.Text;
class Program {
static void Main(string[] args) {
uint utf32 = uint.Parse("1D0EC", System.Globalization.NumberStyles.HexNumber);
string s = Encoding.UTF32.GetString(BitConverter.GetBytes(utf32));
foreach (char c in s.ToCharArray()) {
Console.WriteLine("{0:X}", (uint)c);
}
Console.ReadLine();
}
}

Convert each sequence with int.Parse(String, NumberStyles) and char.ConvertFromUtf32:
string s = #"\U1D0EC";
string converted = char.ConvertFromUtf32(int.Parse(s.Substring(2), NumberStyles.HexNumber));

I have recently push my FOSS Uncode Converter at Codeplex (http://unicode.codeplex.com)
you can convert whatever you want to Hex code and from Hex code to get the right character, also there is a full information character database.
I use this code
public static char ConvertHexToUnicode(string hexCode)
{
if (hexCode != string.Empty)
return ((char)int.Parse(hexCode, NumberStyles.AllowHexSpecifier));
char empty = new char();
return empty;
}//end
you can see entire code on the http://unicode.codeplex.com/

It appears you just want this in your code... you can type it as a string literal using the escape code \Uxxxxxxxx (note that this is a capital U, and there must be 8 digits). For this example, it would be: "\U0001D0EC".