uncrypt / unpack PinBlock

[João Luiz]

Hi People!!! :-)

I have hard task do decript a pinblock, but not understand how to make using jpos!!

Succes using this site: https://emvlab.org/pinblock/

PINblock  1781F8275BDDA0D3
PAN 0000375602171111
Key with Hex / ZPK  5AFFEB76124DD79C2AF54B09D8F70561

decripted 045755FFFFFFFFFF

my pass = 5755 ....

But no way to descrypt with JPOS ... 

    public static String test_dataDecrypt(String cryptogram,String key) throws Exception {
        JCESecurityModule sm = new JCESecurityModule();
        SecureDESKey bdk = new SecureDESKey(SMAdapter.LENGTH_DES3_2KEY,SMAdapter.TYPE_PVK+":0X",key,"6FB1C8");
        byte[] cleartext = sm.dataDecrypt(bdk, cryptogram.getBytes());
        return cleartext.toString();
    }

TKS !!!! :-) 

[Andrés Alcarraz]

Hi Joao.

The method you are using is for decrypting data (not necessarily a PIN Block) using a BDK, not a ZPK. And also, that BDK should be encrypted with the LMK of the Security module, which I don't see you are setting when instantiating.

Also, the idea is that you don't decrypt a PIN Block, but just translate to another key or validate it using the PVV or the PIN offset.

If you want to do that anyway using that approach, you'll have to import your ZPK under the LMK, then create a BDK, translate the pin block to that BDK and then perform the data decrypt.

Best regards

Andrés Alcarraz

El 14/10/22 a las 12:18, João Luiz escribió:

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[João Luiz]

Tks Andrés!! :-D

Have examples from this?  "Also, the idea is that you don't decrypt a PIN Block, but just translate to another key or validate it using the PVV or the PIN offset."

but..... And if I created a pinblock to compare with what arrived, would that work????

like this (extracted from examples, but not accept zpmKey  :-(        org.jpos.security.SMException: Invalid key code: LMK0x0004      )

public static String CreatePinBlock() throws Exception {        
    JCESecurityModule jcesecmod = new JCESecurityModule();
    String pin = "5755";
    String pan = "900320007371";
    String zpkKey = "5AFFEB76124DD79C2AF54B09D8F70561";
    SecureDESKey sdk = new SecureDESKey(SMAdapter.LENGTH_DES3_2KEY, SMAdapter.TYPE_ZPK, zpkKey, "026268");
    EncryptedPIN pinUnderLMK = jcesecmod.encryptPINImpl(pin, pan);
    System.out.println("pinUnderLMK =" + ISOUtil.hexString(pinUnderLMK.getPINBlock()));
    EncryptedPIN pinUnderZPK = jcesecmod.exportPINImpl(pinUnderLMK, sdk, SMAdapter.FORMAT00);
    System.out.println("pinUnderZPK =" + ISOUtil.hexString(pinUnderZPK.getPINBlock()));
    return "";
}  

 

Produced PINBlock to compare with received PinBlock

tks :-)

[João Luiz]

Hi !!!

Success using this https://gist.github.com/ozkansari/65fa143b2018bb7c2efaf44e76d89e62

If any testing PinBlock decode, this code have the solution

Thanks very mutch :-D