NETWPIN Calculation

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ehsan alizadeh
New member
Username: Ehsan123

Post Number: 11
Registered: 09-2005
Posted on Saturday, October 06, 2007 - 02:09 pm:   

Hi,
I used NowSMS for generating a simple OTA with Network PIN and the WBXML is like this:
030B6A0674657374310045C6560187070683000101C655018707068300018711060374657374315F 4E415049440001871006AB0187080603746573743200018709068901871401C65A01870C069A0187 0D060367707273757365726E616D650001870E06036770727370617373776F72640001010101
As I generate the Mac by an imaginary IMSI like : 123456789012345 then MAC will be :
42433144394139324231363943394144413036363139304435303746304432453331434444464146
but the MAC that NowSMS generate for it is:
43343833454332354637453345304346313030333830444135463637313443463230344135454335
I want to know if you use a specific method to calculate Mac by NETWPIN?
because if I generate MAC by USERPIN it is the same as NowSMS one.
Malcolm - Now Support
Moderator
Username: Malcolm

Post Number: 203
Registered: 12-2006
Posted on Thursday, October 18, 2007 - 09:22 pm:   

The calculations for USERPIN and NETWPIN are definitely different.

If you specified the same PIN value ... and sent it once with USERPIN, and another with NETWPIN ... the resulting MAC values would be different for the two cases.

The algorithm for creating the MAC is the same, but the IMSI gets some transformation before the MAC is calculated.

Are you using a particular web form in NowSMS? Maybe that web form is not setting the PINTYPE=NETWPIN value correctly ...
ehsan alizadeh
New member
Username: Ehsan123

Post Number: 12
Registered: 09-2005
Posted on Thursday, October 18, 2007 - 09:30 pm:   

Thanks Malcolm,
you have said that IMSI gets some transformation before the MAC is calculated, I didn't have transformed it before calculating the MAC.
Now I want to know what is the transformation? and how should I calculate the transformed IMSI?
Malcolm - Now Support
Moderator
Username: Malcolm

Post Number: 223
Registered: 12-2006
Posted on Thursday, October 18, 2007 - 11:01 pm:   

Enable the SMSDEBUG.LOG in NowSMS, and if you submit a message to be signed with NETWPIN, you will see an entry in the SMSDEBUG.LOG that says something to the effect of "Encoded IMSI is ..."

That will give you the hex string encoding of the IMSI transformation. The actual data that is used for signing the MAC is binary for the NETWPIN.

The IMSI encoding is defined in Section 6.1 of the OMA Provisioning Bootstrap manual, which references ETSI GSM 11.11/3GPP TS 11.11 (Section 10.3.2).