New-AzureACSSharePointAppRegSecret.ps1

#requires -modules "AzureAD"

Connect-AzureAD

$clientId = 'aa326a3b-706a-4a7c-a96f-1a7e371e967x'

$endDate   = [DateTime]::Today.AddYears(2)
$startDate = [Datetime]::Today

$app = Get-AzureADServicePrincipal -Filter "AppId eq '$clientId'"

$base64secret = New-AzureADServicePrincipalPasswordCredential -ObjectId $app.ObjectId -EndDate $endDate

$null = New-AzureADServicePrincipalKeyCredential -ObjectId $app.ObjectId -StartDate $startDate -EndDate $endDate -Type Symmetric -Usage Verify -Value $base64secret.Value
$null = New-AzureADServicePrincipalKeyCredential -ObjectId $app.ObjectId -StartDate $startDate -EndDate $endDate -Type Symmetric -Usage Sign   -Value $base64secret.Value

[PSCustomObject] @{
    ClientId  = $clientId
    Secret    = [Convert]::ToBase64String( [System.Text.Encoding]::UTF8.GetBytes($base64secret.Value) )
    StartDate = $startDate
    EndDate   = $endDate
}