Re: [Trustedjava-support] convert string Nonce to TcBlobdata

[Martin P. <Mar...@ia...>]

Hi...

Saurabh Arora wrote:
> I wish this group was more active in co-operation.

Considering the number of downloads, yes, this list is surprisingly quiet.
But this may be because open source allows anyone to just "dive" into
the source and figure out why something is not working as expected.
No external dependencies, isn't that great?


> On 6/15/07, Saurabh Arora <tan...@gm...> wrote:
>>On 6/14/07, Thomas Winkler <tc...@to...> wrote:
>>>>>>how can i convert a 160 bit string nonce to TcBlobData type in
>>>>>>jTSSWrapper library ?
>>>
>>>The nonce you have is a Java String?
>>>
>>>In case you are using jTSS Wrapper < 0.3 use the following code:
>>>
>>>TcBlobData blob =
>>>TcTssStructFactory.newBlobData().initStringASCII("yourNonce");
>>>
>>>In case you are using jTSS Wrapper 0.3 use the following code:
>>>
>>>TcBlobData blob = TcBlobData.newStringASCII("yourNonce");
>>
>>it worked.. but now i get another error :
>>"nonce in quote does not match expected nonce"
>>
>>I want to do a quote operation using my "nonce".
>>the sample (working)  quote code uses :
>>-------
>>TcBlobData nonce = context_.getTpm().getRandom(
>>                                TcTcpaDefines.TCPA_SHA1BASED_NONCE_LEN);
>>-------

So the sample code uses a nonce of 160bit / 20byte random data.

>>now when i use :
>>---------
>>TcBlobData nonce =
>>TcTssStructFactory.newBlobData().initString*("516ebb86fe1dc24c6099d212ff971b61b0f5137a");
>>---------

It is still not clear what you actually want to achieve.

But lets consider 3 options and see what the actual content of 'nonce' is:

  TcBlobData nonce;

  nonce = TcTssStructFactory.newBlobData().initString("516ebb86fe1dc24c6099d212ff971b61b0f5137a");
  System.out.println("1:\n"+Utils.byteArrayToHexString( nonce.asByteArray()));

  nonce = TcTssStructFactory.newBlobData().initStringASCII("516ebb86fe1dc24c6099d212ff971b61b0f5137a");
  System.out.println("2:\n"+Utils.byteArrayToHexString( nonce.asByteArray()));

  byte[] barray = Utils.hexStringToByteArray("516ebb86fe1dc24c6099d212ff971b61b0f5137a");
  nonce = TcTssStructFactory.newBlobData().initByteArray(barray);
  System.out.println("3:\n"+Utils.byteArrayToHexString( nonce.asByteArray()));

output:

1:
 35 00 31 00 36 00 65 00 62 00 62 00 38 00 36 00
 66 00 65 00 31 00 64 00 63 00 32 00 34 00 63 00
 36 00 30 00 39 00 39 00 64 00 32 00 31 00 32 00
 66 00 66 00 39 00 37 00 31 00 62 00 36 00 31 00
 62 00 30 00 66 00 35 00 31 00 33 00 37 00 61 00
2:
 35 31 36 65 62 62 38 36 66 65 31 64 63 32 34 63
 36 30 39 39 64 32 31 32 66 66 39 37 31 62 36 31
 62 30 66 35 31 33 37 61
3:
 51 6e bb 86 fe 1d c2 4c 60 99 d2 12 ff 97 1b 61
 b0 f5 13 7a


>>it gives me the error while verifying the quoteblob(in the code) :
>>--------
>>
>>TcTcpaQuoteInfo quoteInfo = new TcTcpaQuoteInfo(quoteBlob.getData());
>>                if (!quoteInfo.getExternalData().getEncoded().equals(expectedNonce)) {
>>                        throw new TcException(
>>                                        "nonce in quote does not match expected nonce");
>>                }

Now look at the output of
System.out.println(
 Utils.byteArrayToHexString( quoteInfo.getExternalData().getEncoded().asByteArray())));

what actually is returned, does that match your expectation?

HTH

-- 
Martin Pirker
IAIK, TU Graz