Maskprocessor Description

Maskprocessor is a high-performance word generator with a per-position configurable charset packed into a single stand-alone binary.

For a detailed description of how masks work, see the Mask attack articles.

Advantage over Brute-Force

The reason for doing this and not to stick to the traditional Brute-Force is that we want to reduce the password candidate keyspace to a more efficient one.

Here is a single example. We want to crack the password: Julia1984

In traditional Brute-Force attack we require a charset that contains all upper-case letters, all lower-case letters and all digits (aka “mixalpha-numeric”). The Password length is 9, so we have to iterate through 62^9 (13.537.086.546.263.552) combinations. Lets say we crack with a rate of 100M/s, this requires more than 4 years to complete.

In Mask attack we know about humans and how they design passwords. The above password matches a simple but common pattern. A name and year appended to it. We can also configure the attack to try the upper-case letters only on the first position. It is very uncommon to see an upper-case letter only in the second or the third position. To make it short, with Mask attack we can reduce the keyspace to 522626262610101010 (237.627.520.000) combinations. With the same cracking rate of 100M/s, this requires just 40 minutes to complete.

Disadvantage compared to Brute-Force

There is none. One can argue that the above example is very specific but this does not matter. Even in mask attack we can configure our mask to use exactly the same keyspace as the Brute-Force attack does. The thing is just that this cannot work vice versa.


For each position of the generated password candidates we need to configure a placeholder. If a password we want to crack has the length 8, our mask must consist of 8 placeholders.

  • A mask is a simple string that configures the keyspace of the password candidate engine using placeholders.
  • A placeholder can be either a custom charset variable, a built-in charset variable or a static letter.
  • A variable is indicated by the ? letter followed by one of the built-in charset (l, u, d, s, a) or one of the custom charset variable names (1, 2, 3, 4).
  • A static letter is not indicated by a letter. An exception is if we want the static letter ? itself, which must be written as ??.

Built-in charsets

  • ?l = abcdefghijklmnopqrstuvwxyz
  • ?d = 0123456789
  • ?s = «space»!"#$%&'()*+,-./:;<=>?@[]^_`{|}~
  • ?a = ?l?u?d?s
  • ?b = 0x00 - 0xff

Custom charsets

There are four commandline-parameters to configure four custom charsets.

  • --custom-charset1=CS
  • --custom-charset2=CS
  • --custom-charset3=CS
  • --custom-charset4=CS

These commandline-parameters have four analogue shortcuts called -1, -2, -3 and -4. You can specify the chars directly on the command line.

Password length increment

A Mask attack is always specific to a password length. For example, if we use the mask ”?l?l?l?l?l?l?l?l” we can only crack a password of the length 8. But if the password we try to crack has the length 7 we will not find it. That's why we have to repeat the attack several times, each time with one placeholder added to the mask. This is transparently automated by using the ”--increment” flag.

  • ?l
  • ?l?l
  • ?l?l?l
  • ?l?l?l?l
  • ?l?l?l?l?l
  • ?l?l?l?l?l?l
  • ?l?l?l?l?l?l?l
  • ?l?l?l?l?l?l?l?l


The following commands creates the following password candidates:

command: ?l?l?l?l?l?l?l?l

keyspace: aaaaaaaa - zzzzzzzz

command: -1 ?l?d ?1?1?1?1?1

keyspace: aaaaa - 99999

command: password?d

keyspace: password0 - password9

command: -1 ?l?u ?1?l?l?l?l?l19?d?d

keyspace: aaaaaa1900 - Zzzzzz1999

command: -1 ?dabcdef -2 ?l?u ?1?1?2?2?2?2?2

keyspace: 00aaaaa - ffZZZZZ

command: -1 efghijklmnop ?1?1?1

keyspace: eee - ppp


Author: atom

License: MIT

Maskprocessor Help


maskprocessor [options]... mask


* Startup:

  -V,  --version             Print version
  -h,  --help                Print help

* Increment:

  -i,  --increment=NUM:NUM   Enable increment mode. 1st NUM=start, 2nd NUM=stop
                             Example: -i 4:8 searches lengths 4-8 (inclusive)

* Misc:

       --combinations        Calculate number of combinations
       --hex-charset         Assume charset is given in hex
  -q,  --seq-max=NUM         Maximum number of multiple sequential characters
  -r,  --occurrence-max=NUM  Maximum number of occurrence of a character

* Resources:

  -s,  --start-at=WORD       Start at specific position
  -l,  --stop-at=WORD        Stop at specific position

* Files:

  -o,  --output-file=FILE    Output-file

* Custom charsets:

  -1,  --custom-charset1=CS  User-defineable charsets
  -2,  --custom-charset2=CS  Example:
  -3,  --custom-charset3=CS  --custom-charset1=?dabcdef
  -4,  --custom-charset4=CS  sets charset ?1 to 0123456789abcdef

* Built-in charsets:

  ?l = abcdefghijklmnopqrstuvwxyz
  ?d = 0123456789
  ?s =  !"#$%&'()*+,-./:;<=>?@[\]^_`{|}~
  ?a = ?l?u?d?s
  ?b = 0x00 - 0xff

Maskprocessor Usage Example

Running the program with the mask pass?d. Here “pass” are static characters, ?d stands for numbers, and in general “pass?d” is a mask.

maskprocessor pass?d

There will be the following output:


Count the number of combinations (--combinations), for the “DANIELLE?1?1” mask, in which the user character set (-1) is set as ?u?d?l (all uppercase and lowercase letters, as well as numbers), word length from 8 up to 10 characters (-i 8:10).

maskprocessor --combinations -i 8:10 -1 ?u?d?l DANIELLE?1?1

If you compiled the program from source codes, then your executable file may be named mp64.bin, therefore the command will look like:

./mp64.bin pass?d

How to install Maskprocessor

Installation on Kali Linux

The program is pre-installed on Kali Linux.

To install in the minimum version:

sudo apt install maskprocessor

Run like this:


“maskprocessor: command not found” error even though the newest version of maskprocessor is already installed

When trying to use the program, the error “maskprocessor: command not found” appears, although the newest version of maskprocessor is already installed. Apparently this package is broken in Kali Linux. Therefore, if you receive this error message, install maskprocessor as follows:

sudo apt remove maskprocessor
git clone
cd maskprocessor/src/
sudo mv ./mp64.bin /usr/bin/maskprocessor
maskprocessor -h

Installation on Debian, Linux Mint, Ubuntu

You can download binaries here:

After downloading, it is enough to unpack the archive and run the mp64.bin or mp32.bin file.

Or install from sources.

sudo apt install git
git clone
cd maskprocessor/src/

Run like this:


Installation on BlackArch

The program is pre-installed on BlackArch.

sudo pacman -S maskprocessor

Run like this:


Installing on Windows

Download executables:

Unpack the archive.

Open a command prompt window (Win+x and select “Windows PowerShell” there).

Drag the mp64.exe (or mp32.exe) file to the command line and press ENTER.

Maskprocessor Screenshots

Maskprocessor Tutorials

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