PowerShell function to generate a hash from a file.
function Get-Hash
{
<#
.SYNOPSIS
Calculates the hash on a given file based on the seleced hash algorithm.
https://github.com/RamblingCookieMonster/PSDeploy/blob/master/PSDeploy/Private/Get-Hash.ps1
.DESCRIPTION
Calculates the hash on a given file based on the seleced hash
algorithm. Multiple hashing algorithms can be used with this
command.
.PARAMETER Path
File or files that will be scanned for hashes.
.PARAMETER Algorithm
The type of algorithm that will be used to determine the hash of a
file or files. Default hash algorithm used is SHA256. More then 1
algorithm type can be used.
Available hash algorithms:
- MD5
- SHA1
- SHA256 (Default)
- SHA384
- SHA512
- RIPEM160
.NOTES
Name: Get-FileHash
Author: Boe Prox
Created: 18 March 2013
Modified: 28 Jan 2014
1.1 - Fixed bug with incorrect hash when using multiple algorithms
.OUTPUTS
System.IO.FileInfo.Hash
.EXAMPLE
Get-Hash -Path file.txt
Path SHA256
---- ------
C:\file.txt 5f8c58306e46b23ef45889494e991d6fc9244e5d78bc093f1712b0ce671acc15
Description
-----------
Displays the SHA256 hash for the text file.
.EXAMPLE
Get-Hash -Path .\file.txt -Algorithm MD5,SHA256,RIPEMD160 | Format-List
Path : C:\file.txt
MD5 : cb8e60205f5e8cae268af2b47a8e5a13
SHA256 : 5f8c58306e46b23ef45889494e991d6fc9244e5d78bc093f1712b0ce671acc15
RIPEMD160 : e64d1fa7b058e607319133b2aa4f69352a3fcbc3
Description
-----------
Displays MD5,SHA256 and RIPEMD160 hashes for the text file.
.EXAMPLE
Get-ChildItem -Filter *.exe | Get-Hash -Algorithm MD5
Path MD5
---- ---
C:\handle.exe 50c128c5b28237b3a01afbdf0e546245
C:\PortQry.exe c6ac67f4076ca431acc575912c194245
C:\procexp.exe b4caa7f3d726120e1b835d52fe358d3f
C:\Procmon.exe 9c85f494132cc6027762d8ddf1dd5a12
C:\PsExec.exe aeee996fd3484f28e5cd85fe26b6bdcd
C:\pskill.exe b5891462c9ca5bddfe63d3bae3c14e0b
C:\Tcpview.exe 485bc6763729511dcfd52ccb008f5c59
Description
-----------
Uses pipeline input from Get-ChildItem to get MD5 hashes of executables.
#>
[CmdletBinding(DefaultParameterSetName = 'File')]
Param(
[Parameter( ParameterSetName = 'File',
Position = 0,
Mandatory = $true,
ValueFromPipelineByPropertyName = $true,
ValueFromPipeline = $True)]
[Alias("PSPath", "FullName")]
[string[]]$Path,
[Parameter( ParameterSetName = 'String',
Position = 0,
Mandatory = $true)]
[string[]]$String,
[Parameter(Position = 1)]
[ValidateSet("MD5", "SHA1", "SHA256", "SHA384", "SHA512", "RIPEMD160")]
[string[]]$Algorithm = "SHA256"
)
Process
{
if ($PSCmdlet.ParameterSetName -eq 'File')
{
$Items = $Path
}
elseif ($PSCmdlet.ParameterSetName -eq 'String')
{
$Items = $String
}
$AlgorithmType = switch ($Algorithm)
{
"MD5" { [System.Security.Cryptography.MD5]::Create() }
"SHA1" { [System.Security.Cryptography.SHA1]::Create() }
"SHA256" { [System.Security.Cryptography.SHA256]::Create() }
"SHA384" { [System.Security.Cryptography.SHA384]::Create() }
"SHA512" { [System.Security.Cryptography.SHA512]::Create() }
"RIPEMD160" { [System.Security.Cryptography.RIPEMD160]::Create() }
}
ForEach ($item in $Items)
{
if ($PSCmdlet.ParameterSetName -eq 'File')
{
$item = (Resolve-Path $item).ProviderPath
# If (-Not ([uri]$item).IsAbsoluteUri) {
If (-Not [System.IO.Path]::IsPathRooted($item))
{
Write-Verbose ("{0} is not a full path, using current directory: {1}" -f $item, $pwd)
$item = (Join-Path $pwd $item)
}
If (Test-Path $item -Type Container)
{
Write-Warning ("Cannot calculate hash for directory: {0}" -f $item)
Return
}
$object = New-Object PSObject -Property @{
Path = $item
}
# Open the Stream
$stream = ([IO.StreamReader]$item).BaseStream
foreach ($Type in $AlgorithmType)
{
[string]$hash = -join ($Type.ComputeHash( $stream ) |
ForEach-Object { "{0:x2}" -f $_ })
$null = $stream.Seek(0, 0)
# If multiple algorithms are used, then they will be added to existing object
$object = Add-Member -InputObject $Object -MemberType NoteProperty -Name $Type.GetType().BaseType.Name -Value $Hash -PassThru
}
}
elseif ($PSCmdlet.ParameterSetName -eq 'String')
{
$object = New-Object PSObject -Property @{
String = $item
}
foreach ($Type in $AlgorithmType)
{
[string]$hash = -join ($Type.ComputeHash( [System.Text.Encoding]::UTF8.GetBytes($item) ) |
ForEach-Object { "{0:x2}" -f $_ })
# If multiple algorithms are used, then they will be added to existing object
$object = Add-Member -InputObject $Object -MemberType NoteProperty -Name $Type -Value $Hash -PassThru
}
}
$object.pstypenames.insert(0, 'System.IO.FileInfo.Hash')
# Output an object with the hash, algorithm and path
Write-Output $object
if ($PSCmdlet.ParameterSetName -eq 'File')
{
#Close the stream
$stream.Close()
$stream.Dispose()
}
}
}
}