> Thread-Topic: SignedXML.CheckSignature()/CreateSignature() Alternative?
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> From: =?Utf-8?B?UmFq?= <Raj@discussions.microsoft.com>
> References: <C3DAFAB2-33AD-43FE-8F99-429CAF368D90@microsoft.com>
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> Subject: RE: SignedXML.CheckSignature()/CreateSignature() Alternative?
> Date: Wed, 29 Sep 2004 19:43:02 -0700
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> Thanks Shawn for your response.
> Infact I did read one of your blogs regarding the custom ID Tag which
> exactly suggested the same approach..But as you know my other problem is
> having the URI as "cid:payLoad" rather than having it as an Empty String
or
> starting with #!So I cant even write a derived class for the Reference ..
> Probably I can create a dummy reference and get the digest values for the
> payloads but since I gotta again change the URI to the cid fashion, my
> SignatureValue will become invalid..It would have been great if .NET
> framework would have allowed URIs starting with cid as well or to have a
flag
> as part of SignedXML which will make the class not to resolve references
and
> just give the Signature Value for the SignedInfo.Anyhow based on what I
have,
> seems like Iam left out with no other option other than to manually
implement
> the signature Value logic...
> Can you please confirm if the below logic used for computing signature
value
> is correct?
> Thanks
> Raj
>
>
>
> ""Shawn Farkas [MS]"" wrote:
>
> > Hi Raj,
> >
> > Unfortunately, the .NET XML digital signature classes were not
designed to
> > enable plugging in different protocols. However, if you do not have to
> > make your signature stick to a specific schema, (ie, it doesn't have to
> > have a pre-defined set of references, and transforms), I can think of
two
> > possible workarounds.
> >
> > 1. Instead of using a reference to the data that is to be signed, embed
a
> > DataObject into the signature containing your MIME data.
> > 2. If the data cannot be embeded into the signature, then create a
custom
> > transform, say MyMineResolverTransform. Then add a dummy reference to
your
> > signature, and attach this transform to that reference. When the
transform
> > is invoked, it could resolve the external MIME data and return that as
its
> > result. The signature engine will sign the hash of the data after its
gone
> > through all of the transforms, so this will effectively sign your
external
> > data as well.
> >
> > -Shawn
> > http://blogs.msdn.com/shawnfa
> > --
> > This posting is provided "AS IS" with no warranties, and confers no
rights.
> >
> >
> > Note:
> > For the benefit of the community-at-large, all responses to this
message
> > are best directed to the newsgroup/thread from which they originated.
> > --------------------
> > > Thread-Topic: SignedXML.CheckSignature()/CreateSignature()
Alternative?
> > > thread-index: AcSkPjjI+llRzxEgRIeID5RXIhMIcw==
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> > > From: =?Utf-8?B?UmFq?= <Raj@discussions.microsoft.com>
> > > Subject: SignedXML.CheckSignature()/CreateSignature() Alternative?
> > > Date: Sun, 26 Sep 2004 20:01:02 -0700
> > > Lines: 39
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> > >
> > > Hi,
> > > Iam using SignedXML.CheckSignature() method for validating XMLDSIG
> > > SignedInfo signature value. It works great until u have a reference
which
> > > cant be resolved. My requirement is to sign an MIME attachment which
cant
> > be
> > > directly resolved by SignedInfo class..So Iam trying to manually
> > implement
> > > the computesignature part and checksignature part using the following
code
> > >
> > > For ComputeSignature implementation, Iam using as below
> > >
> > > SHA1Managed sha1 = new SHA1Managed();
> > > byte [] HashValue =
> > > sha1.ComputeHash(Encoding.Default.GetBytes(signinfo));
> > > RSAPKCS1SignatureFormatter RSAFormatter = new
> > > RSAPKCS1SignatureFormatter(Key);
> > > RSAFormatter.SetHashAlgorithm("SHA1");
> > > byte [] SigValue = RSAFormatter.CreateSignature(HashValue);
> > >
> > > For Checksignature implementation, Iam using
> > > byte [] SignedHash =
> > > Encoding.Default.GetBytes(SignatureValue.InnerText);
> > > RSAPKCS1SignatureDeformatter RSADeformatter = new
> > > RSAPKCS1SignatureDeformatter(RSA);
> > > RSADeformatter.SetHashAlgorithm("SHA1");
> > > RSADeformatter.VerifySignature(HashValue, SignedHash)
> > >
> > > But when I create a simple XML with no reference and get the
> > SignatureValue
> > > using the SignedXML.CreateSignature() and validate using the manual