TITLE

    McAgendaDecrypt - Recover your old McAgenda contacts


DESCRIPTION

    McAgenda was a popular phonebook application for AmigaOS created
    by Roberto Bizzarri in 1997. Many users protected their data with
    a password and have since forgotten it.

    This tool decrypts McAgenda.data files WITHOUT needing the original
    password.

    Through reverse engineering, it was discovered that McAgenda's
    "encryption" uses fixed XOR values hardcoded in the program, not
    the user password. The password only serves as a UI lock.


FEATURES

    - Decrypts McAgenda 4.x .data files
    - No password required
    - ARexx version for classic Amiga
    - Python version for modern systems
    - Full source code included
    - Public Domain


USAGE

    ARexx (Amiga):
        rx McAgendaDecrypt.rexx S:McAgenda.data RAM:contacts.txt

    Python (any platform):
        python3 McAgendaDecrypt.py McAgenda.data contacts.txt


CONTENTS

    McAgendaDecrypt/
        McAgendaDecrypt.rexx   - ARexx script
        McAgendaDecrypt.py     - Python 3 script
        McAgendaDecrypt.guide  - AmigaGuide documentation
        README                 - Quick start


REQUIREMENTS

    ARexx version:
        - AmigaOS 2.0+
        - RexxMast

    Python version:
        - Python 3.x
        - Any OS (Windows, macOS, Linux, AmigaOS 4, MorphOS, AROS)


TECHNICAL DETAILS

    McAgenda stores data starting at offset 0x3E in the .data file.
    Each line is XOR-encrypted:
        - Even positions: XOR 0xDF (223)
        - Odd positions:  XOR 0x0B (11)
    The position counter resets at each newline.


HISTORY

    1.0 (2026-01-20)
        - Initial release


DISCLAIMER

    This tool is provided for legitimate data recovery purposes.
    Only use it on files you own or have permission to access.


LICENSE

    Public Domain - Use freely, no restrictions.

 PERMSSN    UID  GID    PACKED    SIZE  RATIO METHOD CRC     STAMP          NAME
---------- ----------- ------- ------- ------ ---------- ------------ -------------
[generic]                    0       0 ****** -lhd- 0000 Jan 20 10:37 McAgendaDecrypt/
[generic]                 1947    4597  42.4% -lh5- 2038 Jan 20 10:29 McAgendaDecrypt/McAgendaDecrypt.guide
[generic]                 1066    2672  39.9% -lh5- 43b4 Jan 20 10:29 McAgendaDecrypt/McAgendaDecrypt.py
[generic]                 1247    3275  38.1% -lh5- cac7 Jan 20 10:29 McAgendaDecrypt/McAgendaDecrypt.rexx
[generic]                  508     971  52.3% -lh5- 4b2d Jan 20 10:37 McAgendaDecrypt/README
---------- ----------- ------- ------- ------ ---------- ------------ -------------
 Total         5 files    4768   11515  41.4%            Jan 21 01:41