VeraCrypt
aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
-rw-r--r--contrib/EncryptData.ps138
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"