PowerShell script to batch password-protect solution ZIP files using weak but compatible encryption as a basic student deterrent.

encrypt_zips.ps1

# Password-protect all ZIP files in current directory
# Password format: BasePassword + first digit found in filename

$basePassword = "PLACEHOLDER"
$sevenZipPath = "C:\Program Files\7-Zip\7z.exe"

# Verify 7-Zip is installed
if (-not (Test-Path $sevenZipPath)) {
    Write-Host "ERROR: 7-Zip not found at $sevenZipPath" -ForegroundColor Red
    Write-Host "Please install 7-Zip or update the path in the script"
    exit
}

# Get all ZIP files in current directory
$zipFiles = Get-ChildItem -Path . -Filter "*.zip"
$totalFiles = $zipFiles.Count

Write-Host "Found $totalFiles ZIP files to process" -ForegroundColor Green
Write-Host ""

$counter = 0
foreach ($zipFile in $zipFiles) {
    $counter++
    $fileName = $zipFile.Name
    
    # Extract first digit from filename
    if ($fileName -match '\d') {
        $firstDigit = $matches[0]
    } else {
        Write-Host "[$counter/$totalFiles] WARNING: No digit found in '$fileName' - SKIPPING" -ForegroundColor Yellow
        continue
    }
    
    $password = $basePassword + $firstDigit
    $tempDir = "temp_extract_$counter"
    
    Write-Host "[$counter/$totalFiles] Processing: $fileName (password ends with: $firstDigit)"
    
    # Extract to temp directory
    & $sevenZipPath x "$($zipFile.FullName)" -o"$tempDir" -y | Out-Null
    
    if ($LASTEXITCODE -ne 0) {
        Write-Host "  ERROR: Failed to extract $fileName" -ForegroundColor Red
        continue
    }
    
    # Delete original ZIP
    Remove-Item $zipFile.FullName -Force
    
    # Repack with password using ZipCrypto (compatible with all OS)
    & $sevenZipPath a -tzip -mem=ZipCrypto -p"$password" "$($zipFile.FullName)" ".\$tempDir\*" | Out-Null
    
    if ($LASTEXITCODE -eq 0) {
        Write-Host "  SUCCESS: Repacked with password" -ForegroundColor Green
    } else {
        Write-Host "  ERROR: Failed to repack $fileName" -ForegroundColor Red
    }
    
    # Clean up temp directory
    Remove-Item $tempDir -Recurse -Force
    
    Write-Host ""
}

Write-Host "Processing complete!" -ForegroundColor Green