Getting hashbytes from XML

10 May 2007 2:04 PM

Han

Hello

How do you get hash bytes from XML?
checksum() and hashBytes() don't work with XML AS IS. I am handling legal
document. I don't want additional convert like nvarchar or something. I
just want to get the hashbytes from pure XML or stream as is.
Currently I am using CLR, but I think there can be shorter way to do that.
Not only hash but also checksum will do because the computing occurs in safe
place, the DB.

    public static byte[] toHash(SqlXml sqx)
    {
        XmlDocument doc=new XmlDocument();
        doc.Load(sqx.CreateReader());
        MemoryStream ms = new MemoryStream();
        doc.Save(ms);
        ms.Position = 0;

        BinaryReader br = new BinaryReader(ms);
        byte[] bs = br.ReadBytes(Int32.Parse(ms.Length.ToString()));

        SHA1Managed sha = new SHA1Managed();
        byte[] hash = sha.ComputeHash(bs);

        return (hash);
    }

11 May 2007 4:48 AM

Han

This morning I got smarter and shortened the code into 3 lines.

>    public static byte[] toHash(SqlBytes sbs)
>    {
>        SHA1Managed sha = new SHA1Managed();
>        byte[] hash = sha.ComputeHash(sbs);
>        return (hash);
>    }

Callere is dbo.toHash(convert(varbinary(max), @xml))

I am even considering remove the CLR. Then the code may be,

hashBytes('sha1', convert(varbinary(max), @xml))

But I discovered dotnet sha1 and SQL Server sha1 return different result.
Even the lengths of the results are different. I prefered dotnet, but I am
studying still, and any recommandation will be appreciated.

Show quote

"Han" <hp4***@kornet.net.korea> wrote in message
news:%23vHtSwwkHHA.4872@TK2MSFTNGP03.phx.gbl...
> Hello
>
> How do you get hash bytes from XML?
> checksum() and hashBytes() don't work with XML AS IS. I am handling legal
> document. I don't want additional convert like nvarchar or something. I
> just want to get the hashbytes from pure XML or stream as is.
> Currently I am using CLR, but I think there can be shorter way to do that.
> Not only hash but also checksum will do because the computing occurs in
> safe place, the DB.
>
>    public static byte[] toHash(SqlXml sqx)
>    {
>        XmlDocument doc=new XmlDocument();
>        doc.Load(sqx.CreateReader());
>        MemoryStream ms = new MemoryStream();
>        doc.Save(ms);
>        ms.Position = 0;
>
>        BinaryReader br = new BinaryReader(ms);
>        byte[] bs = br.ReadBytes(Int32.Parse(ms.Length.ToString()));
>
>        SHA1Managed sha = new SHA1Managed();
>        byte[] hash = sha.ComputeHash(bs);
>
>        return (hash);
>    }
>