AddToADFSFarm.ps1

 <#AddToADFSFarm.ps1
 #>
 param (
    $DomainName,
    $PrimaryADFSServer,
    $AdfsSvcUsername
 )

 #the adfs service account password is encrypted and stored in a local folder
 $localpath = "C:\Program Files\WindowsPowerShell\Modules\Certificates\"
 $Key = (3,4,2,3,56,34,254,222,1,1,2,23,42,54,33,233,1,34,2,7,6,5,35,43)

 #lets get the password and decrypt it

 #get the adfs password first
 $adfspassword = Convertto-SecureString -String (Get-Content -Path $($localpath+"adfspass.key")) -key $key
 $AdfsSvcCreds = New-Object System.Management.Automation.PSCredential($($DomainName+"\"+$AdfsSvcUsername), $adfspassword)
            
 #install the certificate that will be used for ADFS Service
 Import-PfxCertificate -Exportable -Password $adfspassword -CertStoreLocation cert:\localmachine\my -FilePath $($localpath+"adfs_certificate.pfx")
            
 #get thumbprint of certificate
 $cert = Get-ChildItem -Path Cert:\LocalMachine\my | ?{$_.Subject -eq "CN=fs.adfsfarm.com, OU=Free SSL, OU=Domain Control Validated"} 


 #Configure ADFS
 Import-Module ADFS
 
 Add-AdfsFarmNode -CertificateThumbprint $cert.thumbprint -ServiceAccountCredential $AdfsSvcCreds -PrimaryComputerName $PrimaryADFSServer