Writing a SIM card phone book in Python

In the previous article "Reading a SIM card phone book in Python" I presented a program to read the phone book from a SIM card. I will now present the writing part.

Source code

The source code is in 2 parts: usim.py and usim_write.py files.

usim.py is the exact same file as in the previous article.

usim_write.py is:

#!/usr/bin/env python3

from smartcard.util import toBytes, padd
import random
import usim


def get_name():
    # List of firstnames from https://www.data.gouv.fr/fr/datasets/liste-de-prenoms/
    with open(random.choice(['f', 'm'])) as fd:
        lines = list(map(str.strip, fd.readlines()))
    return " ".join([random.choice(lines), random.choice(lines),
                    random.choice(lines)])


def get_number():
    numbers = "0123456789"
    phone = list()
    phone.append(random.choice(numbers) + random.choice(numbers))
    phone.append(random.choice(numbers) + random.choice(numbers))
    phone.append(random.choice(numbers) + random.choice(numbers))
    phone.append(random.choice(numbers) + random.choice(numbers))
    phone.append(random.choice(numbers) + random.choice(numbers))
    return " ".join(phone)


def new_record(size):
    # size-14 characters for the name
    name = get_name()[0:size-14]
    phone = get_number()
    print("name:", name)
    print("phone:", phone)
    record = padd(list(map(ord, name)), size-14) \
        + padd(toBytes("06 A1 " + phone), 14)
    return record


def usim_write(reader_nb):
    # Select the EF ADN
    (size, connection) = usim.usim(reader_nb)

    for nbr in range(1, 250):
        record = new_record(size)
        #  Update record
        header = [0xA0, 0xDC]
        record_idx = nbr
        cmd = header + [record_idx, 0x04, size] + record
        data, sw1, sw2 = connection.transmit(cmd)
        if (sw1, sw2) != (0x90, 0x00):
            return


if __name__ == "__main__":
    import sys
    if 2 == len(sys.argv):
        reader_nb = int(sys.argv[1])
    else:
        reader_nb = 0
    usim_write(reader_nb)

Comments

I wanted to have reasonable names and phone numbers in my phone book. So I generate names by randomly selecting 3 first names from 2 lists: the 50 first (by frequency of use) male first names in French stored in the m file, and the 50 first female first names in French stored in the f file. I got the data from https://www.data.gouv.fr/fr/datasets/liste-de-prenoms/. The original list also contains first names from other languages.

The first 10 lines of m are:

Pierre
Juste
Julien
Olivier
Henri
Jacques
Philippe
Nicolas
Aime
Antoine
[...]

The first 10 lines of f are:

Marie
Victoire
Claire
Marine
Reine
Virginie
Vienne
Solange
Jolie
Marguerite
[...]

For the phone number I just select a random 10-digits number.

Maybe the entries I created are non functional in a real phone. First check it works for you if you want to reuse this code. Also if you plan to reuse my source code you must read "My blog source code license" first.

Output

$ ./usim_write.py 
Available readers:
- Gemalto PC Twin Reader
Using: Gemalto PC Twin Reader
connecting to Gemalto PC Twin Reader
Select MF
> A0 A4 00 00 02 3F 00
<  [] 9F 22
Select DF Telecom
> A0 A4 00 00 02 7F 10
<  [] 9F 22
Select EF ADN
> A0 A4 00 00 02 6F 3A
<  [] 9F 0F
Get Response
> A0 C0 00 00 0F
< 00 00 21 34 6F 3A 04 00 11 FF 22 01 02 01 22 90 00
name: Juliette Claire Fran
phone: 50 47 00 17 44
> A0 DC 01 04 22 4A 75 6C 69 65 74 74 65 20 43 6C 61 69 72 65 20 46 72 61 6E 06 A1 50 47 00 17 44 FF FF FF FF FF FF FF
<  [] 90 00
name: Luc Nicolas Regis
phone: 83 46 67 10 73
> A0 DC 02 04 22 4C 75 63 20 4E 69 63 6F 6C 61 73 20 52 65 67 69 73 FF FF FF 06 A1 83 46 67 10 73 FF FF FF FF FF FF FF
<  [] 90 00
name: Julien Jeremie Serge
phone: 89 07 17 20 07
> A0 DC 03 04 22 4A 75 6C 69 65 6E 20 4A 65 72 65 6D 69 65 20 53 65 72 67 65 06 A1 89 07 17 20 07 FF FF FF FF FF FF FF
<  [] 90 00
[...]

The output is truncated. I do not want to include all the 255 phone numbers.

If I use usim_read.py (with debug disabled) I get:

$ ./usim_read.py 
Available readers:
- Gemalto PC Twin Reader
Using: Gemalto PC Twin Reader
Select MF
Select DF Telecom
Select EF ADN
Get Response
1: Name: Juliette Claire Fra, phone: 0574007144
2: Name: Luc Nicolas Regis.., phone: 3864760137
3: Name: Julien Jeremie Serg, phone: 9870710270
[...]

Note that the phone numbers are reversed by group of 2 digits. 50 47 00 17 44 becomes 0574007144.

Conclusion

It is as easy to write than to read a SIM phone book.

My goal here was to be able to write "realistic" phone book entries so that the usim_read.py has "real" data to read and display.

usim_read.py will be used again in the next episode.