function Get-AuthorizationHeader
{
[cmdletbinding()]
Param(
    [Parameter(
        ValueFromPipeline)]
    [PSCredential]
    $Credential
)

Begin
{
    $f = $MyInvocation.InvocationName
    Write-Verbose -Message "$f - START"
}

Process
{
    if (-not $Credential)
    {
        Write-Warning -Message "Credential parameter is null"
        return
    }

    $userName = $Credential.GetNetworkCredential().UserName
    $pass = $Credential.GetNetworkCredential().Password
    $domain = $Credential.GetNetworkCredential().Domain

    [string]$authString = "$($userName):$pass"

    if (-not [string]::IsNullOrEmpty($domain))
    {
        [string]$authString = "$($userName)@$($domain):$pass"
    }

    $auth = $authString | ConvertTo-Base64
    @{
        "Authorization" = "Basic $auth"
    }
}

End
{
    Write-Verbose -Message "$f - END"
}
}

function ConvertTo-Base64
{
[cmdletbinding()]
Param(
    [Parameter(
        Mandatory,
        ValueFromPipeline)]
    [string[]]
    $InputObject
)
Begin
{
    $f = $MyInvocation.InvocationName
    Write-Verbose -Message "$f - START"
}

Process
{
    foreach ($string in $InputObject)
    {
        $bytes = [System.Text.Encoding]::UTF8.GetBytes($string)
        [System.Convert]::ToBase64String($bytes)
    }
}

End
{
    Write-Verbose -Message "$f - EMD"
}
}