I got a call today from a new SharePoint Admin at a company freaking out because the old admin forgot to write down the SharePoint Farm Passphrase when they departed. Honestly the guy did it on purpose, but that is an ethical issue beyond this post.
So let me quickly give you a way to change it to a brand new passphrase.
Log onto your SharePoint Application Server and go to
Start > All Programs > Microsoft SharePoint 2010 Products > SharePoint 2010 Management Shell….make sure to right click the link and run as administrator.
Next step at the PowerShell prompt input
$passphrase = ConvertTo-SecureString -asPlainText -ForceSet-SPPassPhrase -PassPhrase $passphrase -Confirm
You will be prompted to input a new passphrase in plain text. Next step is to input
Set-SPPassPhrase -PassPhrase $passphrase –Confirm
After inputting the command above you will be asked to reenter the new passphrase this time it will be hashed then it is just a simple case of entering Y(Yes) N(No) to complete the change
That should be it! In case you run into trouble (for example the passphrase fails to propagate to all servers in the farm), you can find more information on how to fix this by running the following command:
Get-Help Set-SPPassPhrase -Detailed
Hope you never have to do this under this situation but just in case.