How to create a custom batch password generator?

Question

I am wanting to create a password generator which uses a list of pre-generated passwords using batch. The following script I am trying to adapt. I want the system to automatically generate a password using the prefix LONDON Also I want a section where we can can change the word if possible. Can anyone assist?

Also, it needs to generate a password from LONDON01 to LONDON100.

@echo off
:Start2
cls
goto Start
:Start
title Welcome to my Password Generator
echo I will make you a new password.
echo Please write the password down somewhere in case you forget it.
echo ----------------------------------------­-----------------------
echo 1) 1 Random Password
echo 2) 5 Random Passwords
echo 3) 10 Random Passwords
echo Input your choice
set input=
set /p input= Choice:
if %input%==1 goto A if NOT goto Start2
if %input%==2 goto B if NOT goto Start2
if %input%==3 goto C if NOT goto Start2
:A
cls
echo Your password is %random%
echo Now choose what you want to do.
echo 1) Go back to the beginning
echo 2) Exit
set input=
set /p input= Choice:
if %input%==1 goto Start2 if NOT goto Start 2
if %input%==2 goto Exit if NOT goto Start 2
:Exit
exit
:B
cls
echo Your 5 passwords are %random%, %random%, %random%, %random%, %random%.
echo Now choose what you want to do.
echo 1) Go back to the beginning
echo 2) Exit
set input=
set /p input= Choice:
if %input%==1 goto Start2 if NOT goto Start 2
if %input%==2 goto Exit if NOT goto Start 2
:C
cls
echo Your 10 Passwords are %random%, %random%, %random%, %random%, %random%, %random%, %random%, %random%, %random%, %random%
echo Now choose what you want to do.
echo 1) Go back to the beginning
echo 2) Exit
set input=
set /p input= Choice:
if %input%==1 goto Start2 if NOT goto Start 2
if %input%==2 goto Exit if NOT goto Start 2

Answer 1

If you want a fairly decent "random", then I would suggest a fast program in C++ or something else (which can be distributed to your office systems). But, if you are stuck on cmd then:

@echo off
set minimum=0
set maximum=100
set pre=LONDON

:A
set randnumber=%random%
if %randnumber% GEQ %minimum% (
if %randnumber% LEQ %maximum% (
echo %pre%%randnumber%
goto END
)
)
goto A
:END

Output Examples:

Shouldn't be too hard to adjust that to work for your situation.

---

Edit:

As a supplement, I wanted to speak to this as many others have:

This is an extremely insecure way to generate passwords and really shouldn't be used for anything outside of locking a phone, perhaps even not that.

A true password generator should have 'salt' that is randomly generated for each password and is always unique. Brute force on your password set (LONDON0 - LONDON100) would take seconds on a mid-line computer.

Instead, you could use Python, something simple like:

import string, random

def genPass(prefix='LONDON', size=8, chars=string.ascii_uppercase + string.ascii_lowercase + string.digits + '@!.&%$'):
    return prefix + ''.join(random.choice(chars) for i in range(size))

print genPass()

Which gets you a much more random, or at least unique, password set. If you want to change anything, just call genPass(prefix='NOTLONDON', size=2) instead, for example.

Answer 2

Namespace: System.Web.Security; GeneratePassword Method

You need to enable .Net 4 in powershell:

1. View powershell home path:

   powershell $pshome

2. Go to powershell home directory:

   cd %windir%\system32\WindowsPowerShell\v1.0

3. Edit powershell.exe.config and powershell_ise.exe.config:

 <?xml version="1.0"?> 
 <configuration> 
     <startup useLegacyV2RuntimeActivationPolicy="true"> 
         <supportedRuntime version="v4.0.30319"/> 
         <supportedRuntime version="v2.0.50727"/> 
     </startup> 
 </configuration>

command-line:

powershell [Reflection.Assembly]::LoadWithPartialName('System.Web')^|Out-Null;1..12^|%{[System.Web.Security.Membership]::GeneratePassword(16,3)}

Output:

}=+TW7Nsq?W(7Pr=
H@^*WKxH{S._79-d
y5Ls@ii+[P;3&P{3
^B%3eBHo|2V!Q{UW
2$(F8;s9prwURA#c
dZ*k(e(F_C%XJv-}
#SP9La)sWBhVh][Z
u7^d3U36N@66vSe+
Z.hH0e$Z/Jdb4CHs
XxkZTxJr.t(|QHn&
C+qOCz2G(MpGZF)W
06ZY&q^E/z9K5cKD

simple password, command-line:

powershell 1..12^|%{$i='';1..7^|%{$i+=[char](Get-Random -min 65 -max 90)};1..2^|%{$i+=(Get-Random -min 10 -max 99)};echo $i}

Output:

VCXJNCA7249
MUIFGHV8240
YOVGWPH8556
FGOEEFR7862
SWOOAQS8714
OLHYSFW4985
WOEHCRN8249
VHPDMLR1991
TKOEMBO7344
FFMJGSJ8325
KLUVAEF8960
LKYVHQH2212

simple password, variant 2, command-line:

powershell 1..3^|%{$i='LONDON-';1..4^|%{$i+=[char](Get-Random -min 65 -max 90)};$i+='-'+(Get-Random -min 1001 -max 9999);echo $i}

Output:

LONDON-UCUT-3323
LONDON-CCCB-5950
LONDON-SNFX-9316

Answer 3

This should fix your existing batch file so it works.

@echo off

set "prefix=LONDON"

:Start2
cls
goto Start

:Start
title Welcome to my Password Generator
echo I will make you a new password.
echo Please write the password down somewhere in case you forget it.
echo ----------------------------------------­-----------------------
echo 1) 1 Random Password
echo 2) 5 Random Passwords
echo 3) 10 Random Passwords
echo Input your choice
set input=
set /p input= Choice:
if "%input%."=="." goto :Start
if %input%==1 goto A
if %input%==2 goto B
if %input%==3 goto C
goto :Start



:A
cls
echo Your password is %prefix%%random%

:reprompt1
echo Now choose what you want to do.
echo 1) Go back to the beginning
echo 2) Exit
set input=
set /p input= Choice:
if "%input%."=="." goto :reprompt1
if %input%==1 goto Start2
if %input%==2 goto Exit
goto :reprompt1

:Exit
goto :EOF
rem exit



:B
cls
echo Your 5 passwords are %prefix%%random%, %prefix%%random%, %prefix%%random%, %prefix%%random%, %prefix%%random%.

:reprompt5
echo Now choose what you want to do.
echo 1) Go back to the beginning
echo 2) Exit
set input=
set /p input= Choice:
if "%input%."=="." goto :reprompt5
if %input%==1 goto Start2
if %input%==2 goto Exit
goto :reprompt5



:C
cls
echo Your 10 Passwords are %prefix%%random%, %prefix%%random%, %prefix%%random%, %prefix%%random%, %prefix%%random%, %prefix%%random%, %prefix%%random%, %prefix%%random%, %prefix%%random%, %prefix%%random%

:reprompt10
echo Now choose what you want to do.
echo 1) Go back to the beginning
echo 2) Exit
set input=
set /p input= Choice:
if "%input%."=="." goto :reprompt10
if %input%==1 goto Start2
if %input%==2 goto Exit
goto :reprompt10

If you need something different, just let me know.

---

Edit:

I just noticed the comment indicating you need the results to be in the range of LONDON01 to LONDON100, so I modified the batch file to do that:

@echo off

set "prefix=LONDON"

:Start2
cls
goto Start

:Start
title Welcome to my Password Generator
echo I will make you a new password.
echo Please write the password down somewhere in case you forget it.
echo ----------------------------------------­-----------------------
echo 1) 1 Random Password
echo 2) 5 Random Passwords
echo 3) 10 Random Passwords
echo Input your choice
set input=
set /p input= Choice:
if "%input%."=="." goto :Start
if %input%==1 goto A
if %input%==2 goto B
if %input%==3 goto C
goto :Start



:A
cls
call :getpws 1
call :showpws 1

:reprompt1
echo Now choose what you want to do.
echo 1) Go back to the beginning
echo 2) Exit
set input=
set /p input= Choice:
if "%input%."=="." goto :reprompt1
if %input%==1 goto Start2
if %input%==2 goto Exit
goto :reprompt1

:Exit

set "pw1="
set "pw2="
set "pw3="
set "pw4="
set "pw5="
set "pw6="
set "pw7="
set "pw8="
set "pw9="
set "pw10="
set "pwcount="
set "pwindex="
set "pwmessage="
set "pwresult="

goto :EOF
rem exit



:B
cls
call :getpws 5
call :showpws 5

:reprompt5
echo Now choose what you want to do.
echo 1) Go back to the beginning
echo 2) Exit
set input=
set /p input= Choice:
if "%input%."=="." goto :reprompt5
if %input%==1 goto Start2
if %input%==2 goto Exit
goto :reprompt5



:C
cls
call :getpws 10
call :showpws 10

:reprompt10
echo Now choose what you want to do.
echo 1) Go back to the beginning
echo 2) Exit
set input=
set /p input= Choice:
if "%input%."=="." goto :reprompt10
if %input%==1 goto Start2
if %input%==2 goto Exit
goto :reprompt10



:getpws

set pwcount=%~1

rem      this step (clear) not totally necessary...
call :clearallpws
for /L %%f in (1,1,%pwcount%) do call :get1pw %%f
goto :EOF



:clearallpws
for /L %%f in (1,1,10) do call :clearpw %%f
goto :EOF



:clearpw
rem clear password numbered by %1

set pwindex=%~1
for /F "usebackq delims=" %%g in (`echo set "pw%pwindex%="`) do %%g
goto :EOF



:get1pw

set pwindex=%~1

rem     get a random number, add a leading 0 to make sure it is at least 2 digits long
set pwresult=0%random%

rem     keep the last two digits
set "pwresult=%pwresult:~-2,2%"

rem     this will now be something from 00 to 99
rem     now add 1
set /a pwresult+=1

rem     this will now be a number from 1 to 100. Add leading "0" for numbers below 10
if %pwresult% LEQ 9 set "pwresult=0%pwresult%"

rem     this will now be a number from 01 to 100. Insert the prefix
set "pwresult=%prefix%%pwresult%

rem     now assign it to pw(n) variable. and return
for /F "usebackq delims=" %%g in (`echo set "pw%pwindex%=%pwresult%"`) do %%g
goto :EOF


:showpws

set pwcount=%~1

set "pwmessage=Your %pwcount% passwords are: %pw1%"
if %pwcount% EQU 1 set "pwmessage=Your password is: %pw1%"

for /L %%g in (2,1,%pwcount%) do call :append1pw %%g
echo %pwmessage%
goto :EOF


:append1pw

set pwindex=%~1
for /F "usebackq delims=" %%h in (`echo set "pwmessage=%pwmessage%, %%pw%pwindex%%%"`) do %%h
goto :EOF