CODEWITHSUNDEEP
apduemvmastercard
Ayodele Sunday
Ayodele Sunday

Reputation: 29

Application Cryptogram Generation and Validation Failure

I am working on a Master Card transaction processing app but still in the development stages. To be able to test my cryptogram validation app, I personalized a card using MChip with the following profile info:

After reading the contributions on these questions, Unable to Generate correct application Cryptogram and Generating Cryptogram Manually, I tried to check for my card's cryptogram version number but tag 0x9F10 was absent on my personalization data and there was no way I could add this tag before personalization. I have tried various cryptogram generation combinations on the Thales HSM but non is returning the same value as that returned by the card.

Being in the development stage with access to the development keys, I have checked to ensure the keys are good, same data passed for the cryptogram generation and at this stage I am completely clueless about what to do. I will appreciate any help I can get on this issue. Thanks

foreach (var tagLen in EMVTag.ParseDOL(crmDolstr))
    {                                    
        requestData.Append(EMVData[tagLen.Split(',')[0]]);
        dolData.AppendFormat("{0}|{1},", tagLen.Split(',')[0], 
            EMVData[tagLen.Split(',')[0]]);
    }
string commandStr = string.Format("80 AE 8000 {0} {1} 00", 
    GetHexLen(requestData.ToString()), requestData.ToString());
byte[] hexData = Helpers.HexStringToBytes(commandStr);
apdu = new APDUCommand(hexData);

public APDUCommand(byte[] apdu)
    {
        if (apdu.Length < 5)
            throw new Exception("Wrong APDU length.");

        this.cla = apdu[OFFSET_CLA];
        this.ins = apdu[OFFSET_INS];
        this.p1 = apdu[OFFSET_P1];
        this.p2 = apdu[OFFSET_P2];
        this.lc = apdu[OFFSET_LC];
        if (this.lc == apdu.Length - 5)
            this.le = (byte) 0;
        else if (this.lc == apdu.Length - 5 - 1)
            this.le = apdu[apdu.Length - 1];
        else
            throw new Exception("Wrong LC value.");
        this.data = new byte[this.lc];
        System.Array.Copy(apdu, OFFSET_CDATA, this.data, 0, 
            this.data.Length);
}

Upvotes: 2

Views: 1555

Answers (1)

Michal Gluchowski
Michal Gluchowski

Reputation: 1237

The data you use (from CDOL) are not sufficient to generate cryptogram. Cryptogram usually includes AIP, ATC and CVR. Please look at the response to the cryptogram generation for IAD as it usually contains also a dynamically generated CVR that is used in the cryptogram generation process.

Upvotes: 1

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