Unable to generate CAP codes for Barclays debit card

[unlobito]

Hi there,

If I use the incorrect PIN, python-emv recognises this and bails.

$ emvtool -p 0000 cap
Invalid PIN

…but when I use the correct PIN, python-emv is unable to generate the CAP code.

$ emvtool -p 1111 cap
Traceback (most recent call last):
  File "/Users/htw/.pyenv/versions/3.6.4/bin/emvtool", line 11, in <module>
    sys.exit(run())
  File "/Users/htw/.pyenv/versions/3.6.4/lib/python3.6/site-packages/emv/command/client.py", line 46, in run
    cli(obj={})
  File "/Users/htw/.pyenv/versions/3.6.4/lib/python3.6/site-packages/click/core.py", line 722, in __call__
    return self.main(*args, **kwargs)
  File "/Users/htw/.pyenv/versions/3.6.4/lib/python3.6/site-packages/click/core.py", line 697, in main
    rv = self.invoke(ctx)
  File "/Users/htw/.pyenv/versions/3.6.4/lib/python3.6/site-packages/click/core.py", line 1066, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
  File "/Users/htw/.pyenv/versions/3.6.4/lib/python3.6/site-packages/click/core.py", line 895, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File "/Users/htw/.pyenv/versions/3.6.4/lib/python3.6/site-packages/click/core.py", line 535, in invoke
    return callback(*args, **kwargs)
  File "/Users/htw/.pyenv/versions/3.6.4/lib/python3.6/site-packages/click/decorators.py", line 17, in new_func
    return f(get_current_context(), *args, **kwargs)
  File "/Users/htw/.pyenv/versions/3.6.4/lib/python3.6/site-packages/emv/command/client.py", line 151, in cap
    click.echo(card.generate_cap_value(ctx.obj['pin'], challenge=challenge, value=amount))
  File "/Users/htw/.pyenv/versions/3.6.4/lib/python3.6/site-packages/emv/card.py", line 118, in generate_cap_value
    self.verify_pin(pin)
  File "/Users/htw/.pyenv/versions/3.6.4/lib/python3.6/site-packages/emv/card.py", line 89, in verify_pin
    res = self.tp.exchange(VerifyCommand(pin))
  File "/Users/htw/.pyenv/versions/3.6.4/lib/python3.6/site-packages/emv/transmission.py", line 51, in exchange
    res = RAPDU.unmarshal(data + [sw1, sw2])
  File "/Users/htw/.pyenv/versions/3.6.4/lib/python3.6/site-packages/emv/protocol/response.py", line 32, in unmarshal
    raise obj
emv.protocol.response.ErrorResponse: <ErrorResponse: "Command not allowed; conditions of use not satisfied">

EMV-CAP is able to successfully generate a code, so it seems the card is okay. I've created this as a separate issue since #6 appears to be related to different error messages.

[russss]

Can you show me the result of emvtool listapps please?

[unlobito]

Apologies for the delay, the requested output is as follows.

┌Applications──────────┬────────────────────────┐
│ Index │ Label        │ ADF                    │
├───────┼──────────────┼────────────────────────┤
│ 0     │ "Visa Debit" │ [A0 00 00 00 03 10 10] │
│ 1     │ "LINK ATM"   │ [A0 00 00 00 29 10 10] │
│ 2     │ "BARCLAYS"   │ [A0 00 00 00 03 80 02] │
└───────┴──────────────┴────────────────────────┘

[russss]

That's curious. My suspicion was that it was selecting the wrong app - at the moment it is hardcoded to select the last app on the card, but as far as I know "BARCLAYS" is the correct app.

python-emv is a bit of a mess, so it's very hard to work out what it's doing differently.

I'm not sure I'm going to be able to work this out without access to a problematic card, but can you let me know the date of issue of the card, and whether it's an unusual card in any way?

[unlobito]

Not an unusual card as far as I know (just a reissue due to name change). Issued early October 2017. I've also reproduced this issue with a card issued early September 2015 (although, compared to this one, it lacks contactless and only has the A0 00 00 00 03 10 10 application)