96Crypt Help

Alter/Forge CRC16/CRC32 of files

    Cyclic Redundancy Checksums (CRCs) can be easily forged. It is very simple to impose a "desired"
    CRC16/CRC32 value on a given file. The forging process, which shows how easily a CRC value can
    be forged, is NOT implemented in any other software program.
    96Crypt provides in its registered version a feature to forge files and apply any desired CRC16
    or CRC32 value on a given file.

    With 96Crypt you can alter/forge either CRC16 or CRC32 value of any selected file.

1. Forge a CRC16 checksum
    To apply a CRC16 checksum value of your choice on a given file, start 96Crypt, select
    the "CRC Protocols" page, select the CRC16 protocol to be forged.
    Enter your 16-bit desired value in the specified field using the Hexadecimal format
    knowing that every hexadecimal digits represents 1 nibble or 4 bits. So 16-bit are
    represented in 4 hexadecimal digits. (ex. 0001 0010 0001 0010  -->  1212)
    When the 4th hexadecimal digit is entered the grayed "Alter CRC16" button turns to red
    enabling this file selection button.



    Click on the red "Alter CRC16" button as shown below.



    This opens a dialog window for multiple file selection, The algorithm used by 96Crypt will try
    to Alter/forge the CRC16 of the selected files into the new enterd CRC16 value!



    The altered/forged file will be written to a NEW file having an additional .crc extension.
    96Crypt will NEVER overwrite any original file with the forged CRC file.



2. Forge a CRC32 checksum
    To apply a CRC32 checksum value of your choice on a given file, start 96Crypt, select
    the "CRC Protocols" page, select the CRC32 protocol to be forged.
    Enter your 32-bit desired value in the specified field using the Hexadecimal format
    knowing that every hexadecimal digits represents 1 nibble or 4 bits. So 32-bit are
    represented in 8 hexadecimal digits. (ex. 1010 1011 1100 1101 1010 1011 1100 1101  -->  abcdabcd)
    When the 8th hexadecimal digit is entered (6th with CRC24), the grayed "Alter CRC32" button turns
    to red enabling this file selection button.



    Click on the red "Alter CRC32" button as shown below.



    This opens a dialog window for multiple file selection, The algorithm used by 96Crypt will try
    to Alter/forge the CRC32 of the selected files into the new enterd CRC32 value!



    The altered/forged file will be written to a NEW file having an additional .crc extension.
    96Crypt will NEVER overwrite any original file with the forged CRC file.

    Note 1:
    The altered/forged file will ALWAYS be written to a NEW file having an additional .crc extension.
    96Crypt will NEVER overwrite any original file with the forged CRC result file.
    For instance, Altering the CRC16/CRC32 of a file called "anyfile.txt" will create
    a NEW file called "anyfile.txt.crc" with the new forged CRC16/CRC32 checksums.

    Note 2:
    Some file(s) CANNOT be correctly forged. Also, some CRC value CANNOT be correctly applied.
    There's a simple solution to manage this situation detailed in the following example:

    If we try to alter the CRC16 (BISYNCH) of a file called "anyfile.txt" into 1a1a.
    96Crypt will create a NEW file called "anyfile.txt.crc" having 1a1a as CRC16 (BISYNCH).
    If this will NOT succeed from the first time, repeat the same procedure by altering
    the CRC16 (BISYNCH) of the file "anyfile.txt.crc" with 1a1a.
    96Crypt will create another NEW file called "anyfile.txt.crc.crc" having 1a1a as CRC16 (BISYNCH).

    Note 3:
    One single CRC protocol can be altered/forged at a time.
    Everytime a CRC protocol is altered/forged, all other CRC protocol checksums will be modified.
    For instance, if we alter the CRC16 (BISYNCH) of a given file into 1a1a. Then we alter
    the CRC16 (X.25-CCITT) of the same file into 2b2b, the CRC16 (BISYNCH) will change and
    will NOT read anymore 1a1a like it was forged at first.

Save & Print CRC16 / CRC32 Results