MSIdentityTools

1.0.0.0

ConvertFrom-JsonWebSignature.ps1

                                <#

.SYNOPSIS

   Convert Json Web Signature (JWS) structure to PowerShell object.

.EXAMPLE

    PS C:\>$MsalToken.IdToken | ConvertFrom-JsonWebSignature

    Convert OAuth IdToken JWS to PowerShell object.

.INPUTS

    System.String

#>

function ConvertFrom-JsonWebSignature {

    [CmdletBinding()]

    [OutputType([PSCustomObject])]

    param (

        # JSON Web Signature (JWS)

        [Parameter(Mandatory=$true, ValueFromPipeline=$true)]

        [string] $InputObject,

        # Content Type of the Payload

        [Parameter(Mandatory=$false)]

        [ValidateSet('text/plain','application/json','application/octet-stream')]

        [string] $ContentType = 'application/json'

    )

    [string[]] $JwsComponents = $InputObject.Split('.')

    switch ($ContentType) {

        'application/octet-stream' { [byte[]] $JwsPayload = $JwsComponents[1] | ConvertFrom-Base64String -Base64Url -RawBytes }

        'text/plain' { [string] $JwsPayload = $JwsComponents[1] | ConvertFrom-Base64String -Base64Url }

        'application/json' { [PSCustomObject] $JwsPayload = $JwsComponents[1] | ConvertFrom-Base64String -Base64Url | ConvertFrom-Json }

        Default { [string] $JwsPayload = $JwsComponents[1] | ConvertFrom-Base64String -Base64Url }

    }

    [PSCustomObject] $JwsDecoded = New-Object PSCustomObject -Property @{

        Header = $JwsComponents[0] | ConvertFrom-Base64String -Base64Url | ConvertFrom-Json

        Payload = $JwsPayload

        Signature = $JwsComponents[2] | ConvertFrom-Base64String -Base64Url -RawBytes

    }

    return $JwsDecoded

}