PowerShell: Get MD5 Hashing Signature of a File

# Get-MD5-Hash.ps1

# Get-FileHash (PowerShell 4.0+) replacement for Windows 2008. Forward-compatible.
function getMd5{
    param(
        $file,
        $md5 = (New-Object -TypeName System.Security.Cryptography.MD5CryptoServiceProvider)
        )
    
    # $hash = [System.BitConverter]::ToString($md5.ComputeHash([System.IO.File]::ReadAllBytes($file))); # This line has the issue of 2GB file size limit    
    try{
        $stream = [System.IO.File]::Open("$file",[System.IO.Filemode]::Open, [System.IO.FileAccess]::Read);
        $hash = [System.BitConverter]::ToString($md5.ComputeHash($stream));
        $stream.Dispose();
        $stream.Close();      
        return $hash;
        }
    catch{
        return $null;
        }
}

# This is an alternative method, utilizing certutil.exe being bundled into the Windows OS for purposes of SSL encryption/decryption
function getHash{
    param(
        $file = "C:\temp\somefile.txt"
        )
    $hash=(certutil -hashfile $file)[1]; #'certutil -hashfile $file MD5' command doesn't work on Windows 2008
    return $hash
}

$file="D:\somefile.exe"
getMd5 -file $file