CMD batch - encode file to base 64 and trim characters and new line

Question

I'm trying to make a batch file from CMD with the following commands:

1. Convert file to base 64 - using certutil command this is how the contents of the base 64 looks like (B64.txt):

2. Trim the base 64 - basically, I want to remove -----BEGIN CERTIFICATE----- and -----END CERTIFICATE----- this part is done, the only thing left is trim the newline characters to make a one liner of base64, because I will be passing this to a request payload.

---

This is what I did so far:

@ECHO OFF 
cd /filePath
certutil -encode sample.pdf B64.txt
type B64.txt | find /V "-----BEGIN CERTIFICATE-----" | find /V "-----END CERTIFICATE-----" > B64.txt

My question is:

1. Using the command find /V* how can I define the new line characters and remove them?

2. Is there a more efficient way to do this?

Can this also be done without assigning the base 64 as a variable? It turns out that the limit for variables is only around 9000 characters, and the base 64 I convert normally has 70,000 characters.

Answer 1

There is a really simple solution using undocumented features of CERTUTIL. You can use the
-ENCODEHEX verb with an undocumented format at the end to directly get your desired output of base 64 all on one line without any headers.

certutil -encodehex -f sample.pdf B64.txt 0x40000001

See the DosTips More Tricks with certutil thread for more information. Especially look at this 4th post for a detailed explanation of all the format options.

Answer 2

• Edit:

You can use a bat/cmd file with a c# code.

Then you will compile it and run it at run time to get all the strings in one line ...

• Usage:

1) Edit: cd /d "D:\Path\to\file\", adding the drive:\and\path\to\your\directory

2) Save this code below as File OneLine.cmd

/* 2>nul & @cls & @echo off & title <nul & title %~nx0 & setlocal enabledelayedexpansion

cd /d "D:\Path\to\file\" && set "_b64_file=%__CD__%\B64.txt"
"%__APPDIR__%certutil.exe" -encode -f ".\sample.pdf" "!_b64_file!" >nul 
for /f "tokens=*" %%c in ('%__APPDIR__%where.exe /r "c:\Windows\Microsoft.NET" csc.exe
')do >2nul >nul "%%~c" /t:exe /out:"%tmp%\OneLine.exe" "%~f0" /platform:anycpu /unsafe+ /w:0 /o /nologo && goto :next

:next 
"%tmp%\OneLine.exe" & 2>nul >nul del /q /f "%tmp%\OneLine.exe" & endlocal && goto :EOF || rem :: */

using System; using System.IO;using System.Text;namespace OneLineB64 {class Program {static void Main(string[] args){
String Path = System.Environment.GetEnvironmentVariable("_b64_file");String alllines = (File.ReadAllText(Path).Replace(Environment.NewLine, ""));
alllines = alllines.Remove(0,27); alllines = alllines.Remove((alllines.Length)-25);File.WriteAllText(Path, alllines);}}}

• Same code in conventional formatting/layout

/* 2>nul & @cls

@echo off 

title <nul
title %~nx0

setlocal enabledelayedexpansion

cd /d "D:\Path\to\file\"
set "_b64_file=%__CD__%\B64.txt"

"%__APPDIR__%certutil.exe" -encode -f ".\sample.pdf" "!_b64_file!" >nul 

for /f "tokens=*" %%c in ('%__APPDIR__%where.exe /r "c:\Windows\Microsoft.NET" csc.exe')do (
   >2nul >nul "%%~c" /t:exe /out:"%tmp%\OneLine.exe" "%~f0" /platform:anycpu /unsafe+ /w:0 /o /nologo && goto :next
   )

:next 
"%tmp%\OneLine.exe"
2>nul >nul del /q /f "%tmp%\OneLine.exe" 

endlocal
goto :EOF

*/

using System;
using System.IO;
using System.Text;

namespace OneLineB64
{
    class Program
    {
        static void Main(string[] args)
        {
         String Path = System.Environment.GetEnvironmentVariable("_b64_file");
         String alllines = (File.ReadAllText(Path).Replace(Environment.NewLine, ""));
         alllines = alllines.Remove(0,27); 
         alllines = alllines.Remove((alllines.Length)-25);
         File.WriteAllText(Path, alllines);
        }
    }
}

---

File Class

SubString/Remove Characters in String

Get System Environment Variable string

Environment.GetEnvironmentVariable Method

---

• /end Edit:

---

Understanding the maximum character limit in the variable length, it is not possible to do it beyond 8191 digits/characters

---

For remove lines you can use only certificate, because this word is present in 1st and last line.

certutil + -f for overwrite file out if exist

type B64.txt^|"%__APPDIR__%find.exe" /v "CERTIFICATE" will ignore the 1st and last line

set "_b64=!_b64!%%~b" will save line by line in the same variable/1 line

>B64.txt echo/!_b64! will replace/overwrite the contents of the file with the value saved in the variable (b64 strings on one line)

@echo off && setlocal enabledelayedexpansion

cd /d "d:\filePath" && set "_b64="<nul

"%__APPDIR__%certutil.exe" -encode -f sample.pdf B64.txt >nul && for /f %%b in (
'type B64.txt^|"%__APPDIR__%find.exe" /v "CERTIFICATE"')do set "_b64=!_b64!%%~b"

>B64.txt set/p "'=!_b64: =!"<nul & endlocal && exit /b 

Same code in conventional layout:

@echo off

setlocal enabledelayedexpansion

cd /d "d:\filePath"
set "_b64="<nul

"%__APPDIR__%certutil.exe" -encode -f sample.pdf B64.txt >nul

for /f %%b in ('type B64.txt^|"%__APPDIR__%find.exe" /v "CERTIFICATE"')do set "_b64=!_b64!%%~b"

>B64.txt set/p "'=!_b64: =!"<nul 

endlocal
goto :EOF

---