$befehl="get-random -maximum 2"
$username = "user1"
$password = 'mypass'
$securePassword = ConvertTo-SecureString $password -AsPlainText -Force
$credential = New-Object System.Management.Automation.PSCredential $username, $securePassword

Invoke-Command -ComputerName 192.168.26.163 -Credential $credential -ScriptBlock {(invoke-expression $befehl)}