Generates a single hash from the contents of a directory

create_directory_hash.ps1

# Define the directory to hash
$dir = "C:\Path\To\Directory"

# Define the hash algorithm to use
$hashAlgorithm = "SHA256"

# Get all files in the directory (including subdirectories)
$files = Get-ChildItem -Path $dir -Recurse | Where-Object {!$_.PSIsContainer}

# Create an empty hash object
$hashObject = [System.Security.Cryptography.HashAlgorithm]::Create($hashAlgorithm)

# Calculate the hash of each file and add it to the hash object
foreach ($file in $files) {
    $stream = [System.IO.File]::OpenRead($file.FullName)
    $hash = $hashObject.ComputeHash($stream)
    $stream.Close()
    $hashString = [System.BitConverter]::ToString($hash).Replace("-", "").ToLower()
    $hashObject.Initialize()
    $hashObject.TransformBlock([System.Text.Encoding]::UTF8.GetBytes($hashString), 0, $hashString.Length, $hashString, 0)
}

# Finalize the hash and convert it to a string
$hashObject.TransformFinalBlock([System.Array]::Empty(), 0, 0)
$grantTotalHash = [System.BitConverter]::ToString($hashObject.Hash).Replace("-", "").ToLower()

# Output the grant-total hash
Write-Output "Grant-total hash: $grantTotalHash"