If you forget your passphrase after installation of sharepoint 2010 long time. You could "reset/Change/retrieve your passphrase in sharepoint 2010" using the following powershell commands.
1. C:\PS>$passphrase = ConvertTo-SecureString -asPlainText -Force
2. C:\PS>Set-SPPassPhrase -PassPhrase $passphrase -Confirm
1. C:\PS>$passphrase = ConvertTo-SecureString -asPlainText -Force
2. C:\PS>Set-SPPassPhrase -PassPhrase $passphrase -Confirm
