[CmdletBinding()]
Param (
    [Parameter(Mandatory=$True, ValueFromPipeline=$True, HelpMessage="Enter an email address to compute hash")]
    [ValidateScript({If ($_ -match "\b[A-Z0-9._%+-]+@(?:[A-Z0-9-]+\.)+[A-Z]{2,4}\b") {$True}
    Else {Throw "The email address $_ is not a valid format."}})]
    [String[]]$Email,
    [ValidateSet('MD5','RIPEMD160','SHA1','SHA256','SHA384','SHA512')]
    [String] $HashAlgorithm = "MD5"
    )