Private/New-LMHeader.ps1

Function New-LMHeader {

    [CmdletBinding()]
    Param (
        [Parameter(Mandatory)]
        $Auth,

        [Parameter(Mandatory)]
        [String]$Method,

        [Parameter(Mandatory)]
        [String]$ResourcePath,

        $Data,

        [Int]$Version = 3,

        [String]$ContentType = "application/json"
    )

    # Use TLS 1.2
    [Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12

    $Header = New-Object "System.Collections.Generic.Dictionary[[String],[String]]"

    If($Auth.Type -eq "Bearer"){
        $Token = [System.Net.NetworkCredential]::new("", $Auth.BearerToken).Password
        $Header.Add("Authorization", "Bearer $Token")
    }
    Else{
        # Get current time in milliseconds...
        $Epoch = [Math]::Round((New-TimeSpan -start (Get-Date -Date "1/1/1970") -end (Get-Date).ToUniversalTime()).TotalMilliseconds)

        # Concatenate general request details...
        If ($Method -eq "GET" -or $Method -eq "DELETE") {
            $RequestVars = $Method + $Epoch + $ResourcePath
        }
        Else {
            $RequestVars = $Method + $Epoch + $Data + $ResourcePath
        }

        # Construct signature...
        $Hmac = New-Object System.Security.Cryptography.HMACSHA256
        $Hmac.Key = [Text.Encoding]::UTF8.GetBytes([System.Net.NetworkCredential]::new("", $Auth.Key).Password)

        $SignatureBytes = $Hmac.ComputeHash([Text.Encoding]::UTF8.GetBytes($RequestVars))
        $SignatureHex = [System.BitConverter]::ToString($SignatureBytes) -replace '-'
        $Signature = [System.Convert]::ToBase64String([System.Text.Encoding]::UTF8.GetBytes($SignatureHex.ToLower()))

        # Construct headers...
        $LMAuth = 'LMv1 ' + $Auth.Id + ':' + $Signature + ':' + $Epoch
        $Header.Add("Authorization", $LMAuth)
    }

    $Header.Add("Content-Type", $ContentType)
    $Header.Add("X-Version", $Version)

    Return $Header
}