1.1 Install Windows Tools

This page explains each step in detail - ideal for beginners.

Visual Studio is Microsoft's development environment. It includes:

• C/C++ Compiler (cl.exe) - compiles the OpenSSL source code
• Linker (link.exe) - creates the final DLLs
• nmake - executes build commands

Option A: Via winget (recommended)

winget install Microsoft.VisualStudio.2022.Community

Option B: Manual Download

1. Go to Visual Studio Downloads
2. Select „Community“ (free)
3. Start the installer

After download, the Visual Studio Installer opens:

1. Click „Modify“ (if already installed) or „Install“
2. Select: „Desktop development with C++„
3. In the right panel, make sure:
   • ☑ MSVC v143 - VS 2022 C++ x64/x86 Build-Tools
   • ☑ Windows 10/11 SDK (latest version)
4. Click „Install“

After installation:

# 1. Open Developer PowerShell (search in Start Menu)
#    or load VS environment manually:
 
& "C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Auxiliary\Build\vcvars64.bat"
 
# 2. Check compiler
cl

Expected output:

Microsoft (R) C/C++ Optimizing Compiler Version 19.xx.xxxxx for x64

The Windows SDK contains header files like stdlib.h, windows.h, etc. Without these, the compiler cannot find basic functions.

Normally the SDK is installed with Visual Studio. If not:

winget install Microsoft.WindowsSDK.10.0.22621

Or via Visual Studio Installer:

1. „Individual Components“ tab
2. Search: „Windows SDK“
3. Select version 10.0.22621 or newer

# Check if SDK folder exists
Test-Path "C:\Program Files (x86)\Windows Kits\10\Include"

Should output True.

Perl is a scripting language. OpenSSL uses Perl scripts for:

• Configure - Detects the system and creates build files
• Code generation for different platforms

There are several Perl distributions for Windows:

• Strawberry Perl - Recommended, includes everything needed, easy to install
• ActivePerl - Commercial, not recommended
• Cygwin Perl - Can work, but more complicated

winget install StrawberryPerl.StrawberryPerl

Default installation path: C:\Strawberry\perl\bin

Open new terminal, then:

perl -v

Expected output:

This is perl 5, version 38, subversion 2 (v5.38.2)

NASM is an assembler - it translates assembly code into machine code.

OpenSSL contains hand-optimized assembly routines for:

• AES encryption (up to 10x faster!)
• SHA hash functions
• Other cryptographic operations

Without NASM: OpenSSL compiles but uses slower C implementations.

winget install NASM.NASM

# Typical NASM path (may vary!)
$nasmPath = "$env:LOCALAPPDATA\bin\NASM"
 
# Check if folder exists
if (Test-Path $nasmPath) {
    Write-Host "NASM found in: $nasmPath"
} else {
    # Check alternative paths
    Get-ChildItem -Path "C:\" -Filter "nasm.exe" -Recurse -ErrorAction SilentlyContinue |
        Select-Object -First 1 -ExpandProperty DirectoryName
}

Then set PATH (temporary for this session):

$env:PATH = "$nasmPath;$env:PATH"

nasm -v

Expected output:

NASM version 2.16.01 compiled on Dec 21 2023

Git is a version control system. You need it to:

• Download OpenSSL source code from GitHub
• Select the correct version (tag)

winget install Git.Git

git --version

Expected output:

git version 2.43.0.windows.1

After installing all tools, the following should work:

# Load Visual Studio environment
& "C:\Program Files\Microsoft Visual Studio\2022\Community\VC\Auxiliary\Build\vcvars64.bat"
 
# Check all tools
cl          # → Microsoft (R) C/C++ Optimizing Compiler...
perl -v     # → This is perl 5...
nasm -v     # → NASM version 2.xx...
git --version # → git version 2.xx...

• 2. Download Sources
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Wolfgang van der Stille @ EMSR DATA d.o.o. - Post-Quantum Cryptography Professional