diff options
Diffstat (limited to 'contrib/EncryptData.ps1')
| -rw-r--r-- | contrib/EncryptData.ps1 | 38 |
1 files changed, 33 insertions, 5 deletions
diff --git a/contrib/EncryptData.ps1 b/contrib/EncryptData.ps1 index 34fc447a..841baa88 100644 --- a/contrib/EncryptData.ps1 +++ b/contrib/EncryptData.ps1 @@ -23,7 +23,7 @@ The desired path for the VeraCrypt container. If not specified, it defaults to t .NOTES Author: Mounir IDRASSI Email: mounir.idrassi@idrix.fr -Date: July 2023 +Date: 26 July 2024 License: This script is licensed under the Apache License 2.0 #> @@ -77,8 +77,10 @@ $veraCryptFormatExe = Join-Path $veracryptPath "VeraCrypt Format.exe" # Constants used to calculate the size of the exFAT filesystem $InitialVBRSize = 32KB +$BackupVBRSize = 32KB $InitialFATSize = 128KB $ClusterSize = 32KB # TODO : make this configurable +$UpCaseTableSize = 128KB # Typical size function Get-ExFATSizeRec { param( @@ -142,7 +144,7 @@ function Get-ExFATSize { try { # Initialize total size - $totalSize = $InitialVBRSize + $InitialFATSize + $totalSize = $InitialVBRSize + $BackupVBRSize + $InitialFATSize + $UpCaseTableSize # Call the recursive function $totalSize = Get-ExFATSizeRec -Path $Path -TotalSize $totalSize @@ -151,13 +153,24 @@ function Get-ExFATSize { $totalSize += $ClusterSize # Calculate the size of the Bitmap Allocation Table - $numClusters = $totalSize / $ClusterSize + $numClusters = [math]::Ceiling($totalSize / $ClusterSize) $bitmapSize = [math]::Ceiling($numClusters / 8) $totalSize += $bitmapSize # Adjust the size of the FAT $fatSize = $numClusters * 4 $totalSize += $fatSize - $InitialFATSize + + # Add safety factor to account for potential filesystem overhead + # For smaller datasets (<100MB), we add 1% or 64KB (whichever is larger) + # For larger datasets (>=100MB), we add 0.1% or 1MB (whichever is larger) + # This scaled approach ensures adequate extra space without excessive overhead + $safetyFactor = if ($totalSize -lt 100MB) { + [math]::Max(64KB, $totalSize * 0.01) + } else { + [math]::Max(1MB, $totalSize * 0.001) + } + $totalSize += $safetyFactor # Return the minimum disk size needed to store the exFAT filesystem return $totalSize @@ -171,10 +184,25 @@ function Get-ExFATSize { # Calculate size of the container $containerSize = Get-ExFATSize -Path $inputPath +# Convert to MB and round up to the nearest MB $containerSize = [math]::Ceiling($containerSize / 1MB) -# Add 1 MiB to account for the VeraCrypt headers and reserved areas (256 KiB), plus other overhead -$containerSize += 1 +# Add extra space for VeraCrypt headers, reserved areas, and potential alignment requirements +# We use a sliding scale to balance efficiency for small datasets and adequacy for large ones: +# - For very small datasets (<10MB), add 1MB +# - For small to medium datasets (10-100MB), add 2MB +# - For larger datasets (>100MB), add 1% of the total size +# This approach ensures sufficient space across a wide range of dataset sizes +if ($containerSize -lt 10) { + $containerSize += 1 # Add 1 MB for very small datasets +} elseif ($containerSize -lt 100) { + $containerSize += 2 # Add 2 MB for small datasets +} else { + $containerSize += [math]::Ceiling($containerSize * 0.01) # Add 1% for larger datasets +} + +# Ensure a minimum container size of 2 MB +$containerSize = [math]::Max(2, $containerSize) # Specify encryption algorithm, and hash algorithm $encryption = "AES" |