myhashing.ps1

function Get-StringHash {
    param (
        [Parameter(
            Position=0,
            Mandatory=$true,
            ValueFromPipeline=$true,
            ValueFromPipelineByPropertyName=$true)]
        [string] $ClearString,
        [Parameter(Mandatory=$false)]
        [ValidateSet('md5', 'sha1', 'sha256', 'sha384', 'sha512')]
        [string] $HashAlgorithm = 'sha256'
    )
    $hasher = [System.Security.Cryptography.HashAlgorithm]::Create($HashAlgorithm)
    $hash = $hasher.ComputeHash([System.Text.Encoding]::UTF8.GetBytes($ClearString))
    $hashString = [System.BitConverter]::ToString($hash)
    $hashString.Replace('-', '')
}

function Get-URLHash {
    param (
        [Parameter(
            Position=0,
            Mandatory=$true,
            ValueFromPipeline=$true,
            ValueFromPipelineByPropertyName=$true)]
        [string] $URL,
        [Parameter(Mandatory=$false)]
        [ValidateSet('md5', 'sha1', 'sha256', 'sha384', 'sha512')]
        [string] $HashAlgorithm = 'sha256'
    )
    $hasher = [System.Security.Cryptography.HashAlgorithm]::Create($HashAlgorithm)
    $hash = $hasher.ComputeHash([System.Net.WebRequest]::Create($URL).GetResponse().GetResponseStream())
    $hashString = [System.BitConverter]::ToString($hash)
    $hashString.Replace('-', '')
}