Powershell code for parsing next update time from CRL

Read-CRLExpectedExpires.ps1

function Read-CRLExpectedExpires {
    param (
        [String] $crlPath
    )
    try
    {
	    $crlbytes = (Invoke-WebRequest -UseBasicParsing -Uri $crlPath).Content
    }
    catch 
    {
        return $_.Exception.Message
    }
    $CRLReader = [System.Formats.Asn1.AsnReader]::new($crlbytes, [System.Formats.Asn1.AsnEncodingRules]::DER)
    $CertificateList = $CRLReader.ReadSequence()
    $TBSCertList = $CertificateList.ReadSequence()
    $VersionTag = [System.Formats.Asn1.Asn1Tag]::new([System.Formats.Asn1.TagClass]::Universal, 2, $false)
    if ($VersionTag -eq $TBSCertList.PeekTag())
    {
        $version = $TBSCertList.ReadInteger()
    }
    
    $signature = $TBSCertList.ReadSequence()
    $issuer = $TBSCertList.ReadSequence()
    $thisUpdate = $TBSCertList.ReadUtcTime()
    $NextUpdateTag = [System.Formats.Asn1.Asn1Tag]::new([System.Formats.Asn1.TagClass]::Universal, 23, $false)
    if ($TBSCertList.HasData -and $NextUpdateTag -eq $TBSCertList.PeekTag())
    {
        $nextUpdate = $TBSCertList.ReadUtcTime()
    }
    
    $RevokedCertificatesTag = [System.Formats.Asn1.Asn1Tag]::new([System.Formats.Asn1.TagClass]::Universal, 16, $true)
    if ($TBSCertList.HasData -and $RevokedCertificatesTag -eq $TBSCertList.PeekTag()) {
        $revokedCertificates = $TBSCertList.ReadSequence()
    }

    $CrlExtensionsTag = [System.Formats.Asn1.Asn1Tag]::new([System.Formats.Asn1.TagClass]::ContextSpecific, 0, $true)
    if ($TBSCertList.HasData -and $CrlExtensionsTag -eq $TBSCertList.PeekTag())
    {
        $crlExtensionsContainer = $TBSCertList.ReadSequence($CrlExtensionsTag)
        $crlExtensions = $crlExtensionsContainer.ReadSequence()
        while ($crlExtensions.HasData)
        {
            $ext = $crlExtensions.ReadSequence()
            $oid = $ext.ReadObjectIdentifier()
            if ($oid -eq '1.3.6.1.4.1.311.21.4') # crlNextPublish
            {
                $crlExtBytes = $ext.ReadOctetString()
                $crlExtReader = [System.Formats.Asn1.AsnReader]::new($crlExtBytes, [System.Formats.Asn1.AsnEncodingRules]::DER)
                $crlNextPublish = $crlExtReader.ReadUtcTime()
            }
        }
    }

    return New-Object PsObject -Property @{CRLPath=$crlPath ; Expected=$crlNextPublish ; Expires=$nextUpdate ; SignTime=$thisUpdate}
}