SharePoint App Only Registration Key Renewal script

##################################

## Checking secret working

##################################

$clientSecret = 'xxxxx'

Connect-PnPOnline -Url "https://xxxx.sharepoint.com/sites/DevSite" -ClientId 67c86709-5348-45b9-a16b-9b7a983a20c2 -ClientSecret $clientSecret

Get-PnPConnection

Get-PnPListItem -List LookupList

###################################

## Get all Keys

####################################

$msolcred = get-credential

connect-msolservice -credential $msolcred

$clientId = "67c86709-5348-45b9-a16b-9b7a983a20c2"

$keys = Get-MsolServicePrincipalCredential -AppPrincipalId $clientId

$keys

##################################

## Remove keys

##################################

Remove-MsolServicePrincipalCredential -KeyIds $keys.KeyId -AppPrincipalId $clientId

########################################

## Generate key for 3 years

########################################

$bytes = New-Object Byte[] 32

$rand = [System.Security.Cryptography.RandomNumberGenerator]::Create()

$rand.GetBytes($bytes)

$rand.Dispose()

$newClientSecret = [System.Convert]::ToBase64String($bytes)

$dtStart = [System.DateTime]::Now

$dtEnd = $dtStart.AddYears(3)

New-MsolServicePrincipalCredential -AppPrincipalId $clientId -Type Symmetric -Usage Sign -Value $newClientSecret -StartDate $dtStart  -EndDate $dtEnd

New-MsolServicePrincipalCredential -AppPrincipalId $clientId -Type Symmetric -Usage Verify -Value $newClientSecret   -StartDate $dtStart  -EndDate $dtEnd

New-MsolServicePrincipalCredential -AppPrincipalId $clientId -Type Password -Usage Verify -Value $newClientSecret   -StartDate $dtStart  -EndDate $dtEnd

$newClientSecret

############################################

## Checking secret working again

############################################

Connect-PnPOnline -Url "https://xxxx.sharepoint.com/sites/DevSite" -ClientId 67c86709-5348-45b9-a16b-9b7a983a20c2 -ClientSecret $newClientSecret

Get-PnPListItem -List LookupList