MD5 calculatehash for special characters éàè

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I found some code on this page : http://krishhdax.blogspot.co.il/2014/07/useful-functions-to-use-in-ax2012.html

to calculate a MD5 cash in X++

I works fine, but if I have a string with special characters it gives a different hash code then for example md5 via php gives me, I'm using this to check a string coming from a webservice call.

Does anyone have experience with this ?

This is the code I use :

public static str CalculateHash(str tb)
{

// code taken from : krishhdax.blogspot.co.il/.../useful-functions-to-use-in-ax2012.html
str s;
ClrObject obj;
ClrObject md5;
System.Text.StringBuilder sBuilder;
ClrObject clrStr;
ClrObject clrStrObject;
System.Exception clrException;
System.Array resultByteArray;
int i;
int arrayLength ;
InteropPermission perm;

perm = new InteropPermission(InteropKind::ClrInterop);
perm.assert();
try
{
obj = System.Text.Encoding::get_ASCII().GetBytes(tb);
md5 = System.Security.Cryptography.MD5::Create();
resultByteArray = md5.ComputeHash(obj);
//BP deviation documented
sBuilder = new System.Text.StringBuilder();
arrayLength = resultByteArray.get_Length() ;
// Loop through each byte of the hashed data
// and format each one as a hexadecimal string.
for (i = 0; i <arrayLength; i++)
{
clrStrObject = resultByteArray.GetValue(i);
clrStr = clrStrObject.ToString('x2');
sBuilder.Append(clrStr);
}

// Return the hexadecimal string.
s = sBuilder.ToString();
}
catch (Exception::CLRError)
{
//BP deviation documented
clrException = CLRInterop::getLastException();
s = clrException.get_Message();
error(s);
throw error("@SYS106158");
}

CodeAccessPermission::revertAssert();
return s;

}

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Martin Dráb 237,805 Most Valuable Professional on at

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It's because you're using ASCII encoding (System.Text.Encoding::get_ASCII()), which doesn't support such characters.

Use a different encoding, such as UTF-8.

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Community Member on at

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I thought that would be the problem, I replaced these lines in my code :

// obj = System.Text.Encoding::get_ASCII().GetBytes(tb);

obj = System.Text.Encoding::get_UTF8().GetBytes(tb);

If I encode the string in PHP and get the MD5 key they are the same.

How do I decode the string back from UTF8 in X++ ?

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Martin Dráb 237,805 Most Valuable Professional on at

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What do you mean by that? MD5 creates a hash, the whole point is that it can't be decoded. Also, the algorithm encodes texts of any length to a fixed-size hash, therefore there is infinite number of plain texts leading to the same hash.

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Brandon Wiese 17,788 on at

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Strings in X++ are Unicode. Why not just use Unicode as is?

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Martin Dráb 237,805 Most Valuable Professional on at

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Unicode is a standard describing a character set; it's not an encoding. UTF-8 is one way of encoding Unicode character set.

If you meant UnicodeEncoding class, it has a misleading name. It actually represents UTF-16.

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Community Member on at

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I thought I would have to send the string, I send along with the MD5 code to check if it comes from a trusted origin, in the encoded format, but that is not needed, my code works now, thanks for the tip about the UTF8 !

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