error on implementing CMAC in VS 2003

[Ger-6]

Hello,

I need to implement CMAC message authentication according to NIST
Special Publication 800-38B. I try to use the CMAC module from the
Crypto++ library (version 5.6), but until now I did not succeed.
I first wrote a short test program with some test data as input, so I
can verify the output.
I use Visual studio 2003 and the program is made in C++.
The program compile is okay, but when I run it, the program stops at
the “SetKeyWithIV” the message generated by Visual Studio is:

  "Unhandled exception at <address> in <programName>: Microsoft C++
    exception:
CryptoPP::AlgorithmParametersBase::ParameterNotUsed@<address>"

I have tried several version but this issue keeps coming up.

This is the code:

#include "cmac.h"

USING_NAMESPACE(CryptoPP)

USING_NAMESPACE(std)

BOOL TestCMAC()
{
      byte iv[16];
      byte bKey[16];
      byte bTestdata[8];
      byte bTestDecr[8];
      CMAC<AES > Cmac;

      // fill bKey with test data
      // fill iv with test data
      // fill bTestdata with test data

      Cmac.SetKeyWithIV(bKey, sizeof(bKey), iv, sizeoff(iv));  // Here
the exception comes up


      Cmac.Update(bTestdata, 8);
      return (TRUE);
}

Does anyone have an idea what I am doing wrong?

Ger

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[Wei Dai]

You're getting that error because CMAC doesn't need an IV. Call SetKey
instead.

--------------------------------------------------
From: "Ger" <haven@...>
Sent: Thursday, October 15, 2009 2:07 AM
To: "Crypto++ Users" <cryptopp-users@...>
Subject: error on implementing CMAC in VS 2003

>
> Hello,
>
> I need to implement CMAC message authentication according to NIST
> Special Publication 800-38B. I try to use the CMAC module from the
> Crypto++ library (version 5.6), but until now I did not succeed.
> I first wrote a short test program with some test data as input, so I
> can verify the output.
> I use Visual studio 2003 and the program is made in C++.
> The program compile is okay, but when I run it, the program stops at
> the “SetKeyWithIV” the message generated by Visual Studio is:
>
>  "Unhandled exception at <address> in <programName>: Microsoft C++
>    exception:
> CryptoPP::AlgorithmParametersBase::ParameterNotUsed@<address>"
>
> I have tried several version but this issue keeps coming up.
>
> This is the code:
>
> #include "cmac.h"
>
> USING_NAMESPACE(CryptoPP)
>
> USING_NAMESPACE(std)
>
> BOOL TestCMAC()
> {
>      byte iv[16];
>      byte bKey[16];
>      byte bTestdata[8];
>      byte bTestDecr[8];
>      CMAC<AES > Cmac;
>
>      // fill bKey with test data
>      // fill iv with test data
>      // fill bTestdata with test data
>
>      Cmac.SetKeyWithIV(bKey, sizeof(bKey), iv, sizeoff(iv));  // Here
> the exception comes up
>
>
>      Cmac.Update(bTestdata, 8);
>      return (TRUE);
> }
>
> Does anyone have an idea what I am doing wrong?
>
> Ger
>
> >
>

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[Ger-6]

Thank you, I have now succesfully done some CMAC calculations.

I have one remaining problem: when the message is e.g. 6 byte,
according to the specification Padding bytes have to be added till the
correct block size is reached (eg 8 bytes). The first padding byte has
to be 0x80 the others 0x00. When I do this the output is not as
expected. In the next attempt I did not provide padding bytes and pass
the real length to the Updata function (eg. 6). This also did not give
the expected output.

The code I am using:

        CMAC<AES> Cmac;

// Fill bKey; bTestdata with testdata : result in bTestDecr

        Cmac.SetKey(bKey, sizeof(bKey));
        Cmac.Update(bTestdata, sizeof(bTestdata));
        Cmac.Final(bTestDecr);

Can anyone tell me what I do wrong ?

Regards,
Ger

On 20 okt, 02:25, "Wei Dai" <wei...@...> wrote:

> You're getting that error because CMAC doesn't need an IV. Call SetKey
> instead.
>
> --------------------------------------------------
> From: "Ger" <ha...@...>
> Sent: Thursday, October 15, 2009 2:07 AM
> To: "Crypto++ Users" <cryptopp-users@...>
> Subject: error on implementing CMAC in VS 2003
>
>
>
>
>
> > Hello,
>
> > I need to implement CMAC message authentication according to NIST
> > Special Publication 800-38B. I try to use the CMAC module from the
> > Crypto++ library (version 5.6), but until now I did not succeed.
> > I first wrote a short test program with some test data as input, so I
> > can verify the output.
> > I use Visual studio 2003 and the program is made in C++.
> > The program compile is okay, but when I run it, the program stops at
> > the “SetKeyWithIV” the message generated by Visual Studio is:
>
> >  "Unhandled exception at <address> in <programName>: Microsoft C++
> >    exception:
> > CryptoPP::AlgorithmParametersBase::ParameterNotUsed@<address>"
>
> > I have tried several version but this issue keeps coming up.
>
> > This is the code:
>
> > #include "cmac.h"
>
> > USING_NAMESPACE(CryptoPP)
>
> > USING_NAMESPACE(std)
>
> > BOOL TestCMAC()
> > {
> >      byte iv[16];
> >      byte bKey[16];
> >      byte bTestdata[8];
> >      byte bTestDecr[8];
> >      CMAC<AES > Cmac;
>
> >      // fill bKey with test data
> >      // fill iv with test data
> >      // fill bTestdata with test data
>
> >      Cmac.SetKeyWithIV(bKey, sizeof(bKey), iv, sizeoff(iv));  // Here
> > the exception comes up
>
> >      Cmac.Update(bTestdata, 8);
> >      return (TRUE);
> > }
>
> > Does anyone have an idea what I am doing wrong?
>
> > Ger- Tekst uit oorspronkelijk bericht niet weergeven -
>
> - Tekst uit oorspronkelijk bericht weergeven -

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