Reading ELS (Elektroniczna Legitymacja Studencka) data on Linux

read_els.py

# TODO: verify signatures
# TODO: clean up the APDU code

# Some documentation on the ELS format: https://isap.sejm.gov.pl/isap.nsf/download.xsp/WDU20062241634/O/D20061634.pdf

from smartcard.System import readers
from binascii import hexlify, unhexlify
from pyasn1_modules import rfc2315
from pyasn1.codec.der.decoder import decode as der_decoder
from pyasn1.type import univ
import sels

SELECT_FILE = [0x00, 0xA4, 0x04, 0x00, 0x07]
READ_FILE = [0x00, 0xA4, 0x00, 0x00, 0x02]
GET_RESPONSE = [0xA0, 0xC0, 0x00, 0x00]
READ_BINARY = [0x00, 0xB0]

DF_SELS = [0xD6, 0x16, 0x00, 0x00, 0x30, 0x01, 0x01]
EF_CERT = [0x00, 0x01]
EF_ELS = [0x00, 0x02]

for reader in readers():
    if "Virtual" in reader.name:
        continue
    connection = reader.createConnection()
    connection.connect()
    print("ATR", hexlify(bytes(connection.getATR())).decode())

    response, sw1, sw2 = connection.transmit(SELECT_FILE + DF_SELS + [0x00])
    assert sw1 == 0x61  # Command successfully executed; ‘XX’ bytes of data are available and can be requested using GET RESPONSE.
    num_bytes = sw2
    response, sw1, sw2 = connection.transmit(GET_RESPONSE + [num_bytes])
    #print(hexlify(bytes([sw1, sw2])).decode(), hexlify(bytes(response)).decode())

    response, sw1, sw2 = connection.transmit(READ_FILE + EF_ELS + [0x00])
    assert sw1 == 0x61  # Command successfully executed; ‘XX’ bytes of data are available and can be requested using GET RESPONSE.
    num_bytes = sw2
    response, sw1, sw2 = connection.transmit(GET_RESPONSE + [num_bytes])
    #print(hexlify(bytes([sw1, sw2])).decode(), hexlify(bytes(response)).decode())

    offset = 0x0000
    block_size = 0x80
    data = b""
    while True:
        response, sw1, sw2 = connection.transmit(READ_BINARY + [(offset >> 8) & 0xFF, offset & 0xFF] + [block_size])
        #print(hexlify(bytes([sw1, sw2])).decode(), hexlify(bytes(response)).decode())
        data += bytes(response)
        if sw1 == 0x90:
            offset += block_size
        elif sw1 == 0x6C:  # Bad length value in Le; ‘xx’ is the correct exact Le
            block_size = sw2
        elif sw1 == 0x6b and sw2 == 0x00:  # Wrong parameter(s) P1-P2
            break
        else:
            assert False

    print(hexlify(data).decode())

    contentInfo, rest_of_input = der_decoder(data, asn1Spec=rfc2315.ContentInfo())
    signedData, rest_of_input = der_decoder(contentInfo['content'], asn1Spec=rfc2315.contentTypeMap[contentInfo['contentType']])
    infoEncoded, rest_of_input = der_decoder(signedData['contentInfo']['content'], asn1Spec=univ.OctetString())
    info, rest_of_input = der_decoder(infoEncoded, asn1Spec=sels.SELSInfo())
    print(info)

sels.asn1

SELS DEFINITIONS ::= BEGIN
    id-SELSInfo OBJECT IDENTIFIER ::= {iso(1) member-body(2) pl(616) organization(1) gov(101) moneas(4) pki(1) sels(1) 1}

    SELSInfo ::= SEQUENCE {
        wersja              INTEGER {v1(1)},
        numerSeryjnyUkladu  PrintableString (SIZE (8..16)),
        nazwaUczelni        UTF8String (SIZE (1..128)),
        nazwiskoStudenta    SEQUENCE OF
                            UTF8String (SIZE (1..28)),
        imionaStudenta      SEQUENCE OF
                            UTF8String (SIZE (1..24)),
        numerAlbumu         PrintableString (SIZE (1..16)),
        numerEdycji         PrintableString (SIZE (1)),
        numerPesel          PrintableString (SIZE (11)),
        dataWaznosci        GeneralizedTime
    }
END

sels.py

# Auto-generated by asn1ate v.0.6.1.dev0 from sels.asn1
# (last modified on 2022-09-12 00:14:53.138777)

# SELS
from pyasn1.type import univ, char, namedtype, namedval, tag, constraint, useful


def _OID(*components):
    output = []
    for x in tuple(components):
        if isinstance(x, univ.ObjectIdentifier):
            output.extend(list(x))
        else:
            output.append(int(x))

    return univ.ObjectIdentifier(output)


class SELSInfo(univ.Sequence):
    pass


SELSInfo.componentType = namedtype.NamedTypes(
    namedtype.NamedType('wersja', univ.Integer(namedValues=namedval.NamedValues(('v1', 1)))),
    namedtype.NamedType('numerSeryjnyUkladu', char.PrintableString().subtype(subtypeSpec=constraint.ValueSizeConstraint(8, 16))),
    namedtype.NamedType('nazwaUczelni', char.UTF8String().subtype(subtypeSpec=constraint.ValueSizeConstraint(1, 128))),
    namedtype.NamedType('nazwiskoStudenta', univ.SequenceOf(componentType=char.UTF8String().subtype(subtypeSpec=constraint.ValueSizeConstraint(1, 28)))),
    namedtype.NamedType('imionaStudenta', univ.SequenceOf(componentType=char.UTF8String().subtype(subtypeSpec=constraint.ValueSizeConstraint(1, 24)))),
    namedtype.NamedType('numerAlbumu', char.PrintableString().subtype(subtypeSpec=constraint.ValueSizeConstraint(1, 16))),
    namedtype.NamedType('numerEdycji', char.PrintableString().subtype(subtypeSpec=constraint.ValueSizeConstraint(1, 1))),
    namedtype.NamedType('numerPesel', char.PrintableString().subtype(subtypeSpec=constraint.ValueSizeConstraint(11, 11))),
    namedtype.NamedType('dataWaznosci', useful.GeneralizedTime())
)


id_SELSInfo = _OID(1, 2, 616, 1, 101, 4, 1, 1, 1)