Powershell script to generate a self-signed certificate which is useful for ASP.NET Core 2.0

Self-Signed Certificate Powershell Script.ps1

<#
.DESCRIPTION
SelfSignedCertificate Script

.NOTES
Author: Freist Li
Modified By: Ben Zuill-Smith

Usage:
1) Copy this script to a .ps1 file.
2) Modify the parameters passed to the function on the last line of the script.
3) Run powershell as admin (use `powershell -ExecutionPolicy ByPass -File <script-name>.ps1`)
4) Run the script.
#>

#Create Cert, install Cert to My, install Cert to Root, Export Cert as pfx

Function GenerateSelfSignedCert
{

    Param ($certcn, $password, $certfilepath)

    #Check if the certificate name was used before

    $thumbprintA=(dir cert:\CurrentUser\My -recurse | where {$_.Subject -match "CN=" + $certcn} | Select-Object -Last 1).Thumbprint

    if ($thumbprintA.Length -gt 0)
    {
        Write-Host "Duplicated Cert Name used" -ForegroundColor Cyan

        return
    }
    else
    {
        $thumbprintA = New-SelfSignedCertificate -Subject $certcn -DnsName $certcn -FriendlyName "ASP.NET Core Development" -KeyUsage DigitalSignature -TextExtension @("2.5.29.37={text}1.3.6.1.5.5.7.3.1") -CertStoreLocation cert:\CurrentUser\My |
        ForEach-Object{ $_.Thumbprint}
    }

    #If generated successfully

    if ($thumbprintA.Length -gt 0)
    {
        #query the new installed cerificate again
        $thumbprintB=(dir cert:\CurrentUser\My -recurse | where {$_.Subject -match "CN=" + $certcn} | Select-Object -Last 1).thumbprint 

        #If new cert installed sucessfully with the same thumbprint
        if($thumbprintA -eq $thumbprintB )
        {
            $message = $certcn + " installed into CurrentUser\My successfully with thumprint "+$thumbprintA

            Write-Host $message -ForegroundColor Cyan

            $mypwd = ConvertTo-SecureString -String $password -Force –AsPlainText

            Write-Host "Exporting Certificate as .pfx file" -ForegroundColor Cyan

            Export-PfxCertificate -FilePath $certfilepath -Cert cert:\CurrentUser\My\$thumbprintA -Password $mypwd

            Write-Host "Importing Certificate to CurrentUser\Root" -ForegroundColor Cyan

            Import-PfxCertificate -FilePath $certfilepath -Password $mypwd -CertStoreLocation cert:\CurrentUser\Root
        }
        else
        {
            Write-Host "Thumbprint is not the same between new cert and installed cert." -ForegroundColor Cyan
        }
    }
    else
    {
        $message = $certcn + " is not created"
        Write-Host $message -ForegroundColor Cyan
    }

}

GenerateSelfSignedCert localhost <my-password> dev-ssl-cert.pfx