Authentication -- Step by step process

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1. Calculate HMAC of WBXML document.

2. Convert hash result to hex clear string (ascii).

3. Convert asciiMAC to decimal bytes

4. Convert decimalMAC to HEX

5. Get digest from PUSH headers.

6. Compare calculated digest with the digest extracted from push headers.

7. If both digests are comparable then AUTHENTICATION success.

In Detail :Example

1. HMAC of WBXML Document : 3ae41325f8f67ba7cffe73b52b3b6ab3c301016

2. 3ae4 ==> convert each digit to ASCII 33:3A :3E :34

3. 33:3A :3E :34 ==> If the ASCII is not a decimal number (0-9) convert to alphabet : Convert to alphanumeric

If ASCII > 0x39 its not a decimal number so convert to alphabet

a. 0x33 < 0x39 --> 0x33

b. 0x3A > 0x39 --> 0x61 (0x3A + 0x27 :: converting into lower case alphabet ,

Motorola documents shows they are converting to uppercase alphabet )

c. 0x3E > 0x39 --> 0x65

d. 0x34 < 0x39 --> 0x34

3ae4 ==> 0x33 : 0x61 : 0x65 : 0x34

4. Final hash is of 40 byte string.

Detailed example from SonyEricsson Guide : TESTED

Simple example

This example creates an Internet account with the name PROV_NAP with GPRS as bearer. The authentication username will be "foo" and the password will be "bar".

The PIN code for this document is "1111".

00//TransactionID

06//PDUType:Push

2F//HeadersLength

1F//ValueLength,LongLengthIndicator

2D//ValueLength,

B6//MediaType:application/vnd.wap.connectivity-wbxml(June2000)

91//SECParameter

81//Value:USERPIN(0x01),IsShortInteger(0x80)

92//MACParameter

33616534313332356638

66363762613763666665

37336235326233623661

62336333303130313637

//MACValue:"3ae41325f8f67ba7cffe73b52b3b6ab3c301016"

//AssociatedPINis"1111"

00//Endofstring

//Endofheaders,StartofWBXML

02//WBXMLVersion1.2

0B//DocumentPublicIdentifier:-//WAPFORUM//DTDPROV1.0//EN

6A//Charset:UTF-8

00//StringTableLength:00

45//<wap-provisioning>element,contentincluded

C6//<characteristic>element,attributesincluded,content//included

55//attribute,type="NAPDEF"

01//endoftag

87//<parm/>element,attributesincluded

11//attribute,name="NAPID"

06//attribute,value=

03//inlinestring

50524F565F4E4150 //"PROV_NAP"

00//endofstring

01//endoftagand<parm/>element

87//<parm/>element,attributesincluded

10//attribute,name="BEARER"

06//attribute,value=

AB//"GSM-GPRS"

01//endoftagand<parm/>element

87//<parm/>element,attributesincluded

07//attribute,name="NAME"

06//attribute,value=

03//inlinestring

50524F565F4E4150 //"PROV_NAP"

00//endofstring

01//endoftagand<parm/>element

C6//<characteristic>element,attributesincluded,content//included

5A//attribute,type="NAPAUTHINFO"

01//Endoftag

87//<parm/>element,attributesincluded

0C//attribute,name="AUTHTYPE"

06//attribute,value=

9A//"PAP"

01//endoftagand<parm/>element

87//<parm/>element,attributesincluded

0D//attribute,name="AUTHNAME"

06//attribute,value=

03//inlinestring

666F6F //"foo"

00//endofstring

01//endoftagand<parm/>element

87//<parm/>element,attributesincluded

0E//attribute,name="AUTHSECRET"

06//attribute,value=

03//inlinestring

626172 //"bar"

00//endofstring

01//endoftagand<parm/>element

01//</characteristic>tag,endofelement

01//</characteristic>tag,endofelement

01//</wap-provisioning>tag,endofelement